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The full utilization of broadband solar irradiance is becoming increasingly useful for applications such as long-term space missions, wherein power generation from external sources and regenerative life support systems are essential. Luminescent solar concentrators (LSCs) can be designed to separate sunlight into photosynthetically active radiation (PAR) and non-PAR to simultaneously provide for algae cultivation and electric power generation. However, the efficiency of LSCs suffers from high emission losses. In this work, we show that by shaping the LSC in the form of an elliptic array, rather than the conventional planar configuration, emission losses can be drastically reduced to the point that they are almost eliminated. Numerical results, considering the combined effects of emission, transmission and surface scattering losses show the optical efficiency of the elliptic array LSC is 63%, whereas, in comparison, the optical efficiency for conventional planar LSCs is 47.2%. Further, results from numerical simulations show that elliptic array luminescent solar concentrators can convert non-PAR and green-PAR to electric power with a conversion efficiency of ~17% for AM1.5 and 17.6% for AM0, while transmitting PAR to an underlying photobioreactor to support algae cultivation.
Nima Talebzadeh; Paul G. O’Brien. Elliptic Array Luminescent Solar Concentrators for Combined Power Generation and Microalgae Growth. Energies 2021, 14, 5229 .
AMA StyleNima Talebzadeh, Paul G. O’Brien. Elliptic Array Luminescent Solar Concentrators for Combined Power Generation and Microalgae Growth. Energies. 2021; 14 (17):5229.
Chicago/Turabian StyleNima Talebzadeh; Paul G. O’Brien. 2021. "Elliptic Array Luminescent Solar Concentrators for Combined Power Generation and Microalgae Growth." Energies 14, no. 17: 5229.
This paper computationally explores the optical response of various designs of one-dimensional photonic crystal optical filters comprised of alternating layers of dense zirconia and zirconia aerogel. COMSOL Multiphysics software is used to assess the optical characteristics of the filters. The performance of the filters within a thermophotovoltaic (TPV) system with a blackbody emitter and GaSb PV cell is investigated using two different methods including an ideal case wherein the emitter and PV cell are infinite parallel planes and the Monte Carlo ray-tracing method (MCM) with finite areas of its components. Results show that the optimized filter structure is comprised of two stacks of 5 bilayers with different peak positions stacked to form a single structure. When the optimized filter is used in the ideal TPV configuration, a spectral efficiency of 46%, a system efficiency of 33%, and a power density of 8.5 W/cm2 are achieved at the emitter temperature of 1800 K. According to the MCM code, a TPV system comprised of the optimized filter, an emitter, and a PV cell with equal areas of 2 x 2 cm and a 1 mm gap achieves a spectral efficiency of 45%, a system efficiency of 25% and a power density of 7.8 W/cm2 at the emitter temperature of 1800 K. Moreover, MCM results reveal that when the emitter temperature and gap length are 1800 K and 1 mm, respectively, a maximum system efficiency of 27% is realized at an optimal ratio of 0.75 between the PV cell area and the emitter area.
Atousa Pirvaram; Nima Talebzadeh; Mohsen Rostami; Siu Ning Leung; Paul G. O'Brien. Evaluation of a ZrO2/ZrO2-aerogel one-dimensional photonic crystal as an optical filter for thermophotovoltaic applications. Thermal Science and Engineering Progress 2021, 25, 100968 .
AMA StyleAtousa Pirvaram, Nima Talebzadeh, Mohsen Rostami, Siu Ning Leung, Paul G. O'Brien. Evaluation of a ZrO2/ZrO2-aerogel one-dimensional photonic crystal as an optical filter for thermophotovoltaic applications. Thermal Science and Engineering Progress. 2021; 25 ():100968.
Chicago/Turabian StyleAtousa Pirvaram; Nima Talebzadeh; Mohsen Rostami; Siu Ning Leung; Paul G. O'Brien. 2021. "Evaluation of a ZrO2/ZrO2-aerogel one-dimensional photonic crystal as an optical filter for thermophotovoltaic applications." Thermal Science and Engineering Progress 25, no. : 100968.
High temperature solar receivers can convert concentrated solar power to heat to drive chemical production or mechanical cycles to produce electricity. Transparent windows with selective coatings that reflect thermal radiation can be used to cover receivers to improve their efficiency. However, in parabolic dish concentrators (PDC) these windows can reflect or absorb incoming solar radiation, and may actually reduce the efficiency and power output from PDC receivers. In this work numerical analysis shows that one-dimensional transparent photonic crystal heat mirrors (TPCHMs), which have the form of a modified dielectric mirror, can be designed to be highly transmissive to solar radiation but highly reflective towards thermal radiation. Results show that TPCHMs can be designed to provide significant enhancements to PDC receiver efficiencies operating at lower solar concentration ratios. Specifically, numerical analysis shows efficiency improvements of at least 62%, and 193% compared to either open-face receivers or the case when the receiver window is coated with a transparent conducting oxide film at operating temperatures of 1000 K and 1500 K, respectively. These results suggest that TPCHM covers have potential for enhancing the performance of smaller PDC systems operating at relatively low solar concentration ratios.
Mohsen Rostami; Atousa Pirvaram; Nima Talebzadeh; Paul G. O’Brien. Numerical evaluation of one-dimensional transparent photonic crystal heat mirror coatings for parabolic dish concentrator receivers. Renewable Energy 2021, 171, 1202 -1212.
AMA StyleMohsen Rostami, Atousa Pirvaram, Nima Talebzadeh, Paul G. O’Brien. Numerical evaluation of one-dimensional transparent photonic crystal heat mirror coatings for parabolic dish concentrator receivers. Renewable Energy. 2021; 171 ():1202-1212.
Chicago/Turabian StyleMohsen Rostami; Atousa Pirvaram; Nima Talebzadeh; Paul G. O’Brien. 2021. "Numerical evaluation of one-dimensional transparent photonic crystal heat mirror coatings for parabolic dish concentrator receivers." Renewable Energy 171, no. : 1202-1212.
There is potential to significantly reduce CO2 emissions by increasing the efficiency and reducing the duty cycle of HVAC systems by using smart booster fans and dampers. Smart booster fans fit in the vents within a home, operating quietly on low power (2W) to augment HVAC systems and improve their performance. In this study, a prototype duct system is used to measure and evaluate the ability for smart booster fans and dampers to control airflow to different vents for the purpose of increasing the efficiency of HVAC systems. Four case studies were evaluated: an HVAC system (1) without any fans or dampers, (2) with a fan installed in one vent, but without any dampers, (3) with dampers installed at the vents, but without any fans, and (4) with both fan and dampers installed. The results from both the experimental and numerical evaluation show that the smart booster fan and dampers can significantly improve the airflow at a vent that is underperforming. For example, the airflow at the last vent in a ducting branch was increased from 17 to 37 CFM when a smart booster fan was installed at this vent. Results from the numerical analysis show that for the case of an underperforming vent during the winter season the HVAC running time may be reduced from 24 hr/day to 5.6 hr/day. Furthermore, results from the numerical analysis show the HVAC running time is further reduced to 4.5 hr/day for cases 3 and 4.
Behdad Rezanejadzanjani; Paul G. O’Brien. EVALUATION OF SMART BOOSTER FANS AND DAMPERS FOR ADVANCED HVAC SYSTEMS. Journal of Green Building 2021, 16, 115 -127.
AMA StyleBehdad Rezanejadzanjani, Paul G. O’Brien. EVALUATION OF SMART BOOSTER FANS AND DAMPERS FOR ADVANCED HVAC SYSTEMS. Journal of Green Building. 2021; 16 (2):115-127.
Chicago/Turabian StyleBehdad Rezanejadzanjani; Paul G. O’Brien. 2021. "EVALUATION OF SMART BOOSTER FANS AND DAMPERS FOR ADVANCED HVAC SYSTEMS." Journal of Green Building 16, no. 2: 115-127.
Luminescent solar concentrators (LSCs) are a promising technology for integration and renewable energy generation in buildings because they are inexpensive, lightweight, aesthetically versatile, can concentrate both direct and diffuse light and offer wavelength-selective transparency. LSCs have been extensively investigated for applications involving photovoltaic electricity generation. However, little work has been done to investigate the use of thermal energy generated at the edges of LSCs, despite the potential for harnessing a broad range of solar thermal energy. In this work, Newton’s law of cooling is used to measure the thermal power generated at the edge of LSC modules subjected to solar-simulated radiation. Results show that the dye in single-panel LSC modules can generate 17.9 W/m2 under solar-simulated radiation with an intensity of 23.95 mW/cm2 over the spectral region from 360 to 1000 nm. Assuming a mean daily insolation of 5 kWh/m2, the dye in the single-panel LSC modules can generate ~100 kWh/m2 annually. If the surface area of a building is comparable to its floor space, thermal energy generated from LSCs on the buildings surface could be used to substantially reduce the buildings energy consumption.
Quinn Daigle; Paul G. O’Brien. Heat Generated Using Luminescent Solar Concentrators for Building Energy Applications. Energies 2020, 13, 5574 .
AMA StyleQuinn Daigle, Paul G. O’Brien. Heat Generated Using Luminescent Solar Concentrators for Building Energy Applications. Energies. 2020; 13 (21):5574.
Chicago/Turabian StyleQuinn Daigle; Paul G. O’Brien. 2020. "Heat Generated Using Luminescent Solar Concentrators for Building Energy Applications." Energies 13, no. 21: 5574.
Microalgae has potential for large-scale biofuel production and CO2 remediation, however its growth is energy intensive and easily hindered by contamination, unsuitable conditions, and photosaturation. To mitigate these problems the solar irradiance can be partitioned into photosynthetically active radiation (PAR) and photosynthetically inactive radiation (non-PAR). The PAR can be used for algae growth in a photobioreactor under controlled conditions. The non-PAR can be used to generate electricity in photovoltaic (PV) cells to power the photobioreactor. We present numerical analysis of a luminescent solar spectrum splitter (SSS) that partitions the solar irradiance into PAR and non-PAR to simultaneously power algae cultivation systems and PV cells, respectively. The SSS directs non-PAR to PV cells with emission losses of 6%, and an optical efficiency of 73%. Furthermore, the Shockley-Queisser efficiency limit for non-PAR is calculated to be 24% and the SSS enables a non-PAR conversion efficiency of 15.8% for direct solar irradiance. This is enough power to provide for the cultivation and harvesting processes in the photobioreactor. Results show the generated power can also be used to increase algae growth by 9.3%. The luminescent SSS enables self-powered photobioreactors with increased utilization of space and solar radiation, and higher net energy gain ratios.
Nima Talebzadeh; Mohsen Rostami; Paul G. O’Brien. Elliptic paraboloid-based solar spectrum splitters for self-powered photobioreactors. Renewable Energy 2020, 163, 1773 -1785.
AMA StyleNima Talebzadeh, Mohsen Rostami, Paul G. O’Brien. Elliptic paraboloid-based solar spectrum splitters for self-powered photobioreactors. Renewable Energy. 2020; 163 ():1773-1785.
Chicago/Turabian StyleNima Talebzadeh; Mohsen Rostami; Paul G. O’Brien. 2020. "Elliptic paraboloid-based solar spectrum splitters for self-powered photobioreactors." Renewable Energy 163, no. : 1773-1785.
Solar-driven evaporation is a promising technology with many potential applications including desalination, power generation, purification, sterilization and phase separation. Recently, much research has been directed towards increasing solar-driven evaporation efficiencies with photothermal materials that reside at the air-water interface to provide a localized thermal energy source when subjected to solar radiation. In this work, composite foams of carbon nanoparticles (CNPs) and polydimethylsiloxane (PDMS) were fabricated by a facile salt-leaching technique and used as interfacial receivers for solar evaporation. The inclusion of CNPs significantly increases the solar absorptivity of the foams to ~97% with little impact on their inherently low thermal conductivity. Polyvinyl alcohol (PVA) modification was applied to endow the foams with hydrophilicity, thereby enabling continuous water transport to the air-water interface. An enhanced water evaporation rate of 1.26 kg/m2∙h with a solar-to-evaporation efficiency of 80% was achieved under a relatively low solar input of 850 W/m2. With their simple structure and excellent photothermal performance the PVA-CNP/PDMS foams are promising candidates for solar heating applications.
Shuzhe Wang; Sara M. Almenabawy; Nazir P. Kherani; Siu Ning Leung; Paul O'Brien. Solar-Driven Interfacial Water Evaporation Using Open-Porous PDMS Embedded with Carbon Nanoparticles. ACS Applied Energy Materials 2020, 3, 3378 -3386.
AMA StyleShuzhe Wang, Sara M. Almenabawy, Nazir P. Kherani, Siu Ning Leung, Paul O'Brien. Solar-Driven Interfacial Water Evaporation Using Open-Porous PDMS Embedded with Carbon Nanoparticles. ACS Applied Energy Materials. 2020; 3 (4):3378-3386.
Chicago/Turabian StyleShuzhe Wang; Sara M. Almenabawy; Nazir P. Kherani; Siu Ning Leung; Paul O'Brien. 2020. "Solar-Driven Interfacial Water Evaporation Using Open-Porous PDMS Embedded with Carbon Nanoparticles." ACS Applied Energy Materials 3, no. 4: 3378-3386.
Numerical calculations are performed to determine the potential of using one-dimensional transparent photonic crystal heat mirrors (TPCHMs) as transparent coatings for solar receivers. At relatively low operating temperatures of 500 K, the TPCHMs investigated herein do not provide a significant advantage over conventional transparent heat mirrors that are made using transparent conducting oxide films. However, the results show that TPCHMs can enhance the performance of transparent solar receiver covers at higher operating temperatures. At 1000 K, the amount of radiation reflected by a transparent cover back to the receiver can be increased from 40.4% to 60.0%, without compromising the transmittance of solar radiation through the cover, by using a TPCHM in the place of a conventional transparent mirror with a In2O3:Sn film. For a receiver operating temperature of 1500 K, the amount of radiation reflected back to the receiver can be increased from 25.7% for a cover that is coated with a In2O3:Sn film to 57.6% for a cover with a TPCHM. The TPCHM that is presented in this work might be useful for high-temperature applications where high-performance is required over a relatively small area, such as the cover for evacuated receivers or volumetric receivers in Sterling engines.
Mohsen Rostami; Nima Talebzadeh; Paul G. O’Brien. Transparent Photonic Crystal Heat Mirrors for Solar Thermal Applications. Energies 2020, 13, 1464 .
AMA StyleMohsen Rostami, Nima Talebzadeh, Paul G. O’Brien. Transparent Photonic Crystal Heat Mirrors for Solar Thermal Applications. Energies. 2020; 13 (6):1464.
Chicago/Turabian StyleMohsen Rostami; Nima Talebzadeh; Paul G. O’Brien. 2020. "Transparent Photonic Crystal Heat Mirrors for Solar Thermal Applications." Energies 13, no. 6: 1464.
Gaseous CO2 is transformed to CH4 at ambient temperature at high rates under intense solar-simulated radiation over sputtered Ru supported on Si-based photonic crystals.
Paul G. O’Brien; Kulbir K. Ghuman; Abdinoor A. Jelle; Amit Sandhel; Thomas E. Wood; Joel Y. Y. Loh; Jia Jia; Doug Perovic; Chandra Veer Singh; Nazir P. Kherani; Charles A. Mims; Geoffrey A. Ozin. Enhanced photothermal reduction of gaseous CO2 over silicon photonic crystal supported ruthenium at ambient temperature. Energy & Environmental Science 2018, 11, 3443 -3451.
AMA StylePaul G. O’Brien, Kulbir K. Ghuman, Abdinoor A. Jelle, Amit Sandhel, Thomas E. Wood, Joel Y. Y. Loh, Jia Jia, Doug Perovic, Chandra Veer Singh, Nazir P. Kherani, Charles A. Mims, Geoffrey A. Ozin. Enhanced photothermal reduction of gaseous CO2 over silicon photonic crystal supported ruthenium at ambient temperature. Energy & Environmental Science. 2018; 11 (12):3443-3451.
Chicago/Turabian StylePaul G. O’Brien; Kulbir K. Ghuman; Abdinoor A. Jelle; Amit Sandhel; Thomas E. Wood; Joel Y. Y. Loh; Jia Jia; Doug Perovic; Chandra Veer Singh; Nazir P. Kherani; Charles A. Mims; Geoffrey A. Ozin. 2018. "Enhanced photothermal reduction of gaseous CO2 over silicon photonic crystal supported ruthenium at ambient temperature." Energy & Environmental Science 11, no. 12: 3443-3451.
Mohsen Rostami; Nima Talebzadeh; Paul O'brien. The Design Of Infrared Mirror Coatings For The Enhanced Performance Of Incandescent Lighting. Progress in Canadian Mechanical Engineering 2018, 1 .
AMA StyleMohsen Rostami, Nima Talebzadeh, Paul O'brien. The Design Of Infrared Mirror Coatings For The Enhanced Performance Of Incandescent Lighting. Progress in Canadian Mechanical Engineering. 2018; ():1.
Chicago/Turabian StyleMohsen Rostami; Nima Talebzadeh; Paul O'brien. 2018. "The Design Of Infrared Mirror Coatings For The Enhanced Performance Of Incandescent Lighting." Progress in Canadian Mechanical Engineering , no. : 1.
Abdinoor A. Jelle; Kulbir K. Ghuman; Paul G. O'brien; Mohamad Hmadeh; Amit Sandhel; Doug D. Perovic; Chandra Veer Singh; Charles A. Mims; Geoffrey A. Ozin. Solar Fuels: Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by Nanostructured RuO2 on Silicon Photonic Crystal Support (Adv. Energy Mater. 9/2018). Advanced Energy Materials 2018, 8, 1 .
AMA StyleAbdinoor A. Jelle, Kulbir K. Ghuman, Paul G. O'brien, Mohamad Hmadeh, Amit Sandhel, Doug D. Perovic, Chandra Veer Singh, Charles A. Mims, Geoffrey A. Ozin. Solar Fuels: Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by Nanostructured RuO2 on Silicon Photonic Crystal Support (Adv. Energy Mater. 9/2018). Advanced Energy Materials. 2018; 8 (9):1.
Chicago/Turabian StyleAbdinoor A. Jelle; Kulbir K. Ghuman; Paul G. O'brien; Mohamad Hmadeh; Amit Sandhel; Doug D. Perovic; Chandra Veer Singh; Charles A. Mims; Geoffrey A. Ozin. 2018. "Solar Fuels: Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by Nanostructured RuO2 on Silicon Photonic Crystal Support (Adv. Energy Mater. 9/2018)." Advanced Energy Materials 8, no. 9: 1.
Sunlight‐driven catalytic hydrogenation of CO2 is an important reaction that generates useful chemicals and fuels and if operated at industrial scales can decrease greenhouse gas CO2 emissions into the atmosphere. In this work, the photomethanation of CO2 over highly dispersed nanostructured RuO2 catalysts on 3D silicon photonic crystal supports, achieving impressive conversion rates as high as 4.4 mmol gcat−1 h−1 at ambient temperatures under high‐intensity solar simulated irradiation, is reported. This performance is an order of magnitude greater than photomethanation rates achieved over control samples made of nanostructured RuO2 on silicon wafers. The high absorption and unique light‐harvesting properties of the silicon photonic crystal across the entire solar spectral wavelength range coupled with its large surface area are proposed to be responsible for the high methanation rates of the RuO2 photocatalyst. A density functional theory study on the reaction of CO2 with H2 revealed that H2 splits on the surface of the RuO2 to form hydroxyl groups that participate in the overall photomethanation process.
Abdinoor A. Jelle; Kulbir K. Ghuman; Paul O'Brien; Mohamad Hmadeh; Amit Sandhel; Doug D. Perovic; Chandra Veer Singh; Charles A. Mims; Geoffrey A. Ozin. Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by Nanostructured RuO2 on Silicon Photonic Crystal Support. Advanced Energy Materials 2018, 8, 1 .
AMA StyleAbdinoor A. Jelle, Kulbir K. Ghuman, Paul O'Brien, Mohamad Hmadeh, Amit Sandhel, Doug D. Perovic, Chandra Veer Singh, Charles A. Mims, Geoffrey A. Ozin. Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by Nanostructured RuO2 on Silicon Photonic Crystal Support. Advanced Energy Materials. 2018; 8 (9):1.
Chicago/Turabian StyleAbdinoor A. Jelle; Kulbir K. Ghuman; Paul O'Brien; Mohamad Hmadeh; Amit Sandhel; Doug D. Perovic; Chandra Veer Singh; Charles A. Mims; Geoffrey A. Ozin. 2018. "Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by Nanostructured RuO2 on Silicon Photonic Crystal Support." Advanced Energy Materials 8, no. 9: 1.
This study has designed and implemented a library of hetero‐nanostructured catalysts, denoted as [email protected], comprised of size‐controlled Pd nanocrystals interfaced with Nb2O5 nanorods. This study also demonstrates that the catalytic activity and selectivity of CO2 reduction to CO and CH4 products can be systematically tailored by varying the size of the Pd nanocrystals supported on the Nb2O5 nanorods. Using large Pd nanocrystals, this study achieves CO and CH4 production rates as high as 0.75 and 0.11 mol h−1 gPd−1, respectively. By contrast, using small Pd nanocrystals, a CO production rate surpassing 18.8 mol h−1 gPd−1 is observed with 99.5% CO selectivity. These performance metrics establish a new milestone in the champion league of catalytic nanomaterials that can enable solar‐powered gas‐phase heterogeneous CO2 reduction. The remarkable control over the catalytic performance of [email protected] is demonstrated to stem from a combination of photothermal, electronic and size effects, which is rationally tunable through nanochemistry.
Jia Jia; Hong Wang; Zhuole Lu; Paul G. O'Brien; Mireille Ghoussoub; Paul Duchesne; Ziqi Zheng; Peicheng Li; Qiao Qiao; Lu Wang; Alan Gu; Abdinoor A. Jelle; Yuchan Dong; Qiang Wang; Kulbir Kaur Ghuman; Thomas Wood; Chenxi Qian; Yue Shao; Chenyue Qiu; Miaomiao Ye; Yimei Zhu; Zheng‐Hong Lu; Peng Zhang; Amr S. Helmy; Chandra Veer Singh; Nazir P. Kherani; Doug D. Perovic; Geoffrey A. Ozin. Photothermal Catalyst Engineering: Hydrogenation of Gaseous CO 2 with High Activity and Tailored Selectivity. Advanced Science 2017, 4, 1700252 -1700252.
AMA StyleJia Jia, Hong Wang, Zhuole Lu, Paul G. O'Brien, Mireille Ghoussoub, Paul Duchesne, Ziqi Zheng, Peicheng Li, Qiao Qiao, Lu Wang, Alan Gu, Abdinoor A. Jelle, Yuchan Dong, Qiang Wang, Kulbir Kaur Ghuman, Thomas Wood, Chenxi Qian, Yue Shao, Chenyue Qiu, Miaomiao Ye, Yimei Zhu, Zheng‐Hong Lu, Peng Zhang, Amr S. Helmy, Chandra Veer Singh, Nazir P. Kherani, Doug D. Perovic, Geoffrey A. Ozin. Photothermal Catalyst Engineering: Hydrogenation of Gaseous CO 2 with High Activity and Tailored Selectivity. Advanced Science. 2017; 4 (10):1700252-1700252.
Chicago/Turabian StyleJia Jia; Hong Wang; Zhuole Lu; Paul G. O'Brien; Mireille Ghoussoub; Paul Duchesne; Ziqi Zheng; Peicheng Li; Qiao Qiao; Lu Wang; Alan Gu; Abdinoor A. Jelle; Yuchan Dong; Qiang Wang; Kulbir Kaur Ghuman; Thomas Wood; Chenxi Qian; Yue Shao; Chenyue Qiu; Miaomiao Ye; Yimei Zhu; Zheng‐Hong Lu; Peng Zhang; Amr S. Helmy; Chandra Veer Singh; Nazir P. Kherani; Doug D. Perovic; Geoffrey A. Ozin. 2017. "Photothermal Catalyst Engineering: Hydrogenation of Gaseous CO 2 with High Activity and Tailored Selectivity." Advanced Science 4, no. 10: 1700252-1700252.
TiOx (x < 2) nanoparticles with tunable colors from white to gray to blue–gray to black are synthesized by magnesium (Mg) reduction of white P25 TiO2 nanocrystals followed by removal of excess Mg with aqueous HCl and distilled water. Increasing amounts of Mg smoothly decrease the oxygen content in TiOx which is responsible for the gradual increase in light absorption and concomitant darkening of its color from white to black with decreasing values of x. The as‐synthesized TiOx nanoparticles are spin‐coated onto the surface of a stainless steel mesh followed by surface superhydrophobization in order to test their performance as a solar water evaporator. Results from the tests show that the black TiOx efficiently generates water vapor with a solar thermal conversion efficiency as high as 50% under solar‐simulated light irradiance at an intensity of 1000 W m–2 (1 Sun). Moreover, TiOx nanoparticles have inherent advantages over other materials used for solar water desalination, such as their tunable light absorption, low‐cost, low‐toxicity, superhydrophobicity, and chemical stability.
Miaomiao Ye; Jia Jia; Zhejian Wu; Chenxi Qian; Rong Chen; Paul O'Brien; Wei Sun; Yuchan Dong; Geoffrey A. Ozin. Synthesis of Black TiOxNanoparticles by Mg Reduction of TiO2Nanocrystals and their Application for Solar Water Evaporation. Advanced Energy Materials 2016, 7, 1 .
AMA StyleMiaomiao Ye, Jia Jia, Zhejian Wu, Chenxi Qian, Rong Chen, Paul O'Brien, Wei Sun, Yuchan Dong, Geoffrey A. Ozin. Synthesis of Black TiOxNanoparticles by Mg Reduction of TiO2Nanocrystals and their Application for Solar Water Evaporation. Advanced Energy Materials. 2016; 7 (4):1.
Chicago/Turabian StyleMiaomiao Ye; Jia Jia; Zhejian Wu; Chenxi Qian; Rong Chen; Paul O'Brien; Wei Sun; Yuchan Dong; Geoffrey A. Ozin. 2016. "Synthesis of Black TiOxNanoparticles by Mg Reduction of TiO2Nanocrystals and their Application for Solar Water Evaporation." Advanced Energy Materials 7, no. 4: 1.
Four different polymorphs of nanostructured iron oxyhydroxides, namely; goethite (α-FeOOH), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH), and feroxyhyte (δ-FeOOH) were synthesized and fully characterized by X-ray diffraction, electron microscopy, UV/Visible spectrophotometry, Brunauer–Emmett–Teller (BET) measurements, and X-ray photoemission spectroscopy. The relationship between these iron oxyhydroxide polymorphs and their photocatalytic properties was explored by examining the extent of methylene blue (MB) degradation by each polymorph under visible-light irradiation. Feroxyhyte exhibited the best photocatalytic properties and degraded 85 % of the MB dye in five hours. In comparison, goethite, akaganeite, and lepidocrocite degraded only 40 %, 35 %, and 30 % of the MB in five hours, respectively. To understand this trend, the surface area, particle size and shape, and electronic band properties were systematically studied and discussed. It was found that the rate of MB degradation relates mainly to the surface area of the FeOOH polymorphs more than any other factor. This is the first report of a comparative study of the physical, electronic, and photocatalytic properties of all four polymorphs of nanostructured iron oxyhydroxides.
Abdinoor A. Jelle; Mohamad Hmadeh; Paul G. O'brien; Doug D. Perovic; Geoffrey A. Ozin. Photocatalytic Properties of All Four Polymorphs of Nanostructured Iron Oxyhydroxides. ChemNanoMat 2016, 2, 1047 -1054.
AMA StyleAbdinoor A. Jelle, Mohamad Hmadeh, Paul G. O'brien, Doug D. Perovic, Geoffrey A. Ozin. Photocatalytic Properties of All Four Polymorphs of Nanostructured Iron Oxyhydroxides. ChemNanoMat. 2016; 2 (11):1047-1054.
Chicago/Turabian StyleAbdinoor A. Jelle; Mohamad Hmadeh; Paul G. O'brien; Doug D. Perovic; Geoffrey A. Ozin. 2016. "Photocatalytic Properties of All Four Polymorphs of Nanostructured Iron Oxyhydroxides." ChemNanoMat 2, no. 11: 1047-1054.
Quantum efficiency enhancements are demonstrated in multi-junction photovoltaic cells with Selectively Transparent and Conducting Photonic Crystal (STCPC) intermediate Bragg reflectors.
B. D. A. Ramautarsingh; Paul O'Brien; Andrew Flood; N. P. Kherani. Quantum efficiency enhancement in multi-junction solar cells with spectrally selective and conducting 1D photonic crystals. Journal of Materials Chemistry C 2016, 4, 9276 -9286.
AMA StyleB. D. A. Ramautarsingh, Paul O'Brien, Andrew Flood, N. P. Kherani. Quantum efficiency enhancement in multi-junction solar cells with spectrally selective and conducting 1D photonic crystals. Journal of Materials Chemistry C. 2016; 4 (39):9276-9286.
Chicago/Turabian StyleB. D. A. Ramautarsingh; Paul O'Brien; Andrew Flood; N. P. Kherani. 2016. "Quantum efficiency enhancement in multi-junction solar cells with spectrally selective and conducting 1D photonic crystals." Journal of Materials Chemistry C 4, no. 39: 9276-9286.
The field of solar fuels seeks to harness abundant solar energy by driving useful molecular transformations. Of particular interest is the photodriven conversion of greenhouse gas CO2 into carbon-based fuels and chemical feedstocks, with the ultimate goal of providing a sustainable alternative to traditional fossil fuels. Nonstoichiometric, hydroxylated indium oxide nanoparticles, denoted In2O3–x(OH)y, have been shown to function as active photocatalysts for CO2 reduction to CO via the reverse water gas shift reaction under simulated solar irradiation. However, the relatively wide band gap (2.9 eV) of indium oxide restricts the portion of the solar irradiance that can be utilized to ∼9%, and the elevated reaction temperatures required (150–190 °C) reduce the overall energy efficiency of the process. Herein we report a hybrid catalyst consisting of a vertically aligned silicon nanowire (SiNW) support evenly coated by In2O3–x(OH)y nanoparticles that utilizes the vast majority of the solar irradiance to simultaneously produce both the photogenerated charge carriers and heat required to reduce CO2 to CO at a rate of 22.0 μmol·gcat–1·h–1. Further, improved light harvesting efficiency of the In2O3–x(OH)y/SiNW films due to minimized reflection losses and enhanced light trapping within the SiNW support results in a ∼6-fold increase in photocatalytic conversion rates over identical In2O3–x(OH)y films prepared on roughened glass substrates. The ability of this In2O3–x(OH)y/SiNW hybrid catalyst to perform the dual function of utilizing both light and heat energy provided by the broad-band solar irradiance to drive CO2 reduction reactions represents a general advance that is applicable to a wide range of catalysts in the field of solar fuels.
Laura B. Hoch; Paul G. O’Brien; Abdinoor Jelle; Amit Sandhel; Douglas D. Perovic; Charles A. Mims; Geoffrey A. Ozin. Nanostructured Indium Oxide Coated Silicon Nanowire Arrays: A Hybrid Photothermal/Photochemical Approach to Solar Fuels. ACS Nano 2016, 10, 9017 -9025.
AMA StyleLaura B. Hoch, Paul G. O’Brien, Abdinoor Jelle, Amit Sandhel, Douglas D. Perovic, Charles A. Mims, Geoffrey A. Ozin. Nanostructured Indium Oxide Coated Silicon Nanowire Arrays: A Hybrid Photothermal/Photochemical Approach to Solar Fuels. ACS Nano. 2016; 10 (9):9017-9025.
Chicago/Turabian StyleLaura B. Hoch; Paul G. O’Brien; Abdinoor Jelle; Amit Sandhel; Douglas D. Perovic; Charles A. Mims; Geoffrey A. Ozin. 2016. "Nanostructured Indium Oxide Coated Silicon Nanowire Arrays: A Hybrid Photothermal/Photochemical Approach to Solar Fuels." ACS Nano 10, no. 9: 9017-9025.
Silicon constitutes 28% of the earth's mass. Its high abundance, lack of toxicity and low cost coupled with its electrical and optical properties, make silicon unique among the semiconductors for converting sunlight into electricity. In the quest for semiconductors that can make chemicals and fuels from sunlight and carbon dioxide, unfortunately the best performers are invariably made from rare and expensive elements. Here we report the observation that hydride-terminated silicon nanocrystals with average diameter 3.5 nm, denoted ncSi:H, can function as a single component heterogeneous reducing agent for converting gaseous carbon dioxide selectively to carbon monoxide, at a rate of hundreds of μmol h−1 g−1. The large surface area, broadband visible to near infrared light harvesting and reducing power of SiH surface sites of ncSi:H, together play key roles in this conversion. Making use of the reducing power of nanostructured hydrides towards gaseous carbon dioxide is a conceptually distinct and commercially interesting strategy for making fuels directly from sunlight.
Wei Sun; Chenxi Qian; Le He; Kulbir Kaur Ghuman; Annabelle Po Yin Wong; Jia Jia; Abdinoor A. Jelle; Paul G. O’Brien; Laura M. Reyes; Thomas E. Wood; Amr S. Helmy; Charles A. Mims; Chandra Veer Singh; Geoffrey A. Ozin. Heterogeneous reduction of carbon dioxide by hydride-terminated silicon nanocrystals. Nature Communications 2016, 7, 12553 .
AMA StyleWei Sun, Chenxi Qian, Le He, Kulbir Kaur Ghuman, Annabelle Po Yin Wong, Jia Jia, Abdinoor A. Jelle, Paul G. O’Brien, Laura M. Reyes, Thomas E. Wood, Amr S. Helmy, Charles A. Mims, Chandra Veer Singh, Geoffrey A. Ozin. Heterogeneous reduction of carbon dioxide by hydride-terminated silicon nanocrystals. Nature Communications. 2016; 7 (1):12553.
Chicago/Turabian StyleWei Sun; Chenxi Qian; Le He; Kulbir Kaur Ghuman; Annabelle Po Yin Wong; Jia Jia; Abdinoor A. Jelle; Paul G. O’Brien; Laura M. Reyes; Thomas E. Wood; Amr S. Helmy; Charles A. Mims; Chandra Veer Singh; Geoffrey A. Ozin. 2016. "Heterogeneous reduction of carbon dioxide by hydride-terminated silicon nanocrystals." Nature Communications 7, no. 1: 12553.
The reverse water gas shift (RWGS) reaction driven by Nb2O5 nanorod‐supported Pd nanocrystals without external heating using visible and near infrared (NIR) light is demonstrated. By measuring the dependence of the RWGS reaction rates on the intensity and spectral power distribution of filtered light incident onto the nanostructured [email protected] catalyst, it is determined that the RWGS reaction is activated photothermally. That is the RWGS reaction is initiated by heat generated from thermalization of charge carriers in the Pd nanocrystals that are excited by interband and intraband absorption of visible and NIR light. Taking advantage of this photothermal effect, a visible and NIR responsive [email protected] hybrid catalyst that efficiently hydrogenates CO2 to CO at an impressive rate as high as 1.8 mmol gcat−1 h−1 is developed. The mechanism of this photothermal reaction involves H2 dissociation on Pd nanocrystals and subsequent spillover of H to the Nb2O5 nanorods whereupon adsorbed CO2 is hydrogenated to CO. This work represents a significant enhancement in our understanding of the underlying mechanism of photothermally driven CO2 reduction and will help guide the way toward the development of highly efficient catalysts that exploit the full solar spectrum to convert gas‐phase CO2 to valuable chemicals and fuels.
Jia Jia; Paul O'Brien; Le He; Qiao Qiao; Teng Fei; Laura M. Reyes; Timothy E. Burrow; Yuchan Dong; Kristine Liao; Maria Varela; Stephen J. Pennycook; Mohamad Hmadeh; Amr S. Helmy; Nazir P. Kherani; Doug D. Perovic; Geoffrey A. Ozin. Visible and Near‐Infrared Photothermal Catalyzed Hydrogenation of Gaseous CO 2 over Nanostructured [email protected] 2 O 5. Advanced Science 2016, 3, 1 .
AMA StyleJia Jia, Paul O'Brien, Le He, Qiao Qiao, Teng Fei, Laura M. Reyes, Timothy E. Burrow, Yuchan Dong, Kristine Liao, Maria Varela, Stephen J. Pennycook, Mohamad Hmadeh, Amr S. Helmy, Nazir P. Kherani, Doug D. Perovic, Geoffrey A. Ozin. Visible and Near‐Infrared Photothermal Catalyzed Hydrogenation of Gaseous CO 2 over Nanostructured [email protected] 2 O 5. Advanced Science. 2016; 3 (10):1.
Chicago/Turabian StyleJia Jia; Paul O'Brien; Le He; Qiao Qiao; Teng Fei; Laura M. Reyes; Timothy E. Burrow; Yuchan Dong; Kristine Liao; Maria Varela; Stephen J. Pennycook; Mohamad Hmadeh; Amr S. Helmy; Nazir P. Kherani; Doug D. Perovic; Geoffrey A. Ozin. 2016. "Visible and Near‐Infrared Photothermal Catalyzed Hydrogenation of Gaseous CO 2 over Nanostructured [email protected] 2 O 5." Advanced Science 3, no. 10: 1.
The development of strategies for increasing the lifetime of photoexcited charge carriers in nanostructured metal oxide semiconductors is important for enhancing their photocatalytic activity. Intensive efforts have been made in tailoring the properties of the nanostructured photocatalysts through different ways, mainly including band-structure engineering, doping, catalyst–support interaction, and loading cocatalysts. In liquid-phase photocatalytic dye degradation and water splitting, it was recently found that nanocrystal superstructure based semiconductors exhibited improved spatial separation of photoexcited charge carriers and enhanced photocatalytic performance. Nevertheless, it remains unknown whether this strategy is applicable in gas-phase photocatalysis. Using porous indium oxide nanorods in catalyzing the reverse water–gas shift reaction as a model system, we demonstrate here that assembling semiconductor nanocrystals into superstructures can also promote gas-phase photocatalytic processes. Transient absorption studies prove that the improved activity is a result of prolonged photoexcited charge carrier lifetimes due to the charge transfer within the nanocrystal network comprising the nanorods. Our study reveals that the spatial charge separation within the nanocrystal networks could also benefit gas-phase photocatalysis and sheds light on the design principles of efficient nanocrystal superstructure based photocatalysts.
Le He; Thomas E. Wood; Bo Wu; Yuchan Dong; Laura B. Hoch; Laura M. Reyes; Di Wang; Christian Kübel; Chenxi Qian; Jia Jia; Kristine Liao; Paul O'Brien; Amit Sandhel; Joel Y. Y. Loh; Paul Szymanski; Nazir P. Kherani; Tze Chien Sum; Charles A. Mims; Geoffrey A. Ozin. Spatial Separation of Charge Carriers in In2O3–x(OH)y Nanocrystal Superstructures for Enhanced Gas-Phase Photocatalytic Activity. ACS Nano 2016, 10, 5578 -5586.
AMA StyleLe He, Thomas E. Wood, Bo Wu, Yuchan Dong, Laura B. Hoch, Laura M. Reyes, Di Wang, Christian Kübel, Chenxi Qian, Jia Jia, Kristine Liao, Paul O'Brien, Amit Sandhel, Joel Y. Y. Loh, Paul Szymanski, Nazir P. Kherani, Tze Chien Sum, Charles A. Mims, Geoffrey A. Ozin. Spatial Separation of Charge Carriers in In2O3–x(OH)y Nanocrystal Superstructures for Enhanced Gas-Phase Photocatalytic Activity. ACS Nano. 2016; 10 (5):5578-5586.
Chicago/Turabian StyleLe He; Thomas E. Wood; Bo Wu; Yuchan Dong; Laura B. Hoch; Laura M. Reyes; Di Wang; Christian Kübel; Chenxi Qian; Jia Jia; Kristine Liao; Paul O'Brien; Amit Sandhel; Joel Y. Y. Loh; Paul Szymanski; Nazir P. Kherani; Tze Chien Sum; Charles A. Mims; Geoffrey A. Ozin. 2016. "Spatial Separation of Charge Carriers in In2O3–x(OH)y Nanocrystal Superstructures for Enhanced Gas-Phase Photocatalytic Activity." ACS Nano 10, no. 5: 5578-5586.