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The hydrogen economy relies on effective and environmentally friendly processes for energy conversion and storage. To this end, hydrogen is progressively holding the role of preferred energy vector. Within this frame, electrochemical science and technology is actively contributing in developing advanced fuel cells and water electrolyzers to be integrated in (i) energy parks to decouple production and consumption; (ii) exploit renewable sources; (iii) favour the progressive reduction of fossil fuels and reduce the greenhouse effect via decarbonization. The exploitation of the relevant processes and devices call for the sound control over the environmental impact from production to end-of-life steps. Here, life-cycle analyses were performed and discussed focusing on both acid and alkaline fuel cells, i.e., proton exchange membrane fuel cells (PEMFC) and anion-exchange membrane fuel cells (AEMFC), and assessing their contribution to key environmental impact categories such as, for example, global warming and ozone layer depletion. Within these premises, the study points to the benefits of replacing platinum by low load Pd/CeO2 bifunctional electrocatalyst on electrochemical hydrogen production and usage.
Simone Minelli; Michele Civelli; Sandra Rondinini; Alessandro Minguzzi; Alberto Vertova. AEMFC Exploiting a Pd/CeO2-Based Anode Compared to Classic PEMFC via LCA Analysis. Hydrogen 2021, 2, 246 -261.
AMA StyleSimone Minelli, Michele Civelli, Sandra Rondinini, Alessandro Minguzzi, Alberto Vertova. AEMFC Exploiting a Pd/CeO2-Based Anode Compared to Classic PEMFC via LCA Analysis. Hydrogen. 2021; 2 (3):246-261.
Chicago/Turabian StyleSimone Minelli; Michele Civelli; Sandra Rondinini; Alessandro Minguzzi; Alberto Vertova. 2021. "AEMFC Exploiting a Pd/CeO2-Based Anode Compared to Classic PEMFC via LCA Analysis." Hydrogen 2, no. 3: 246-261.
Molecular platinum clusters can be used for the synthesis of very small (ca. 1.5 nm) Pt nanoparticles with enhanced catalytic activity and stability towards the oxygen reduction reaction. The Pt–C interactions were characterized by TEM and EXAFS.
Martina Fracchia; Paolo Ghigna; Marcello Marelli; Marco Scavini; Alberto Vertova; Sandra Rondinini; Roberto Della Pergola; Alessandro Minguzzi. Molecular cluster route for the facile synthesis of a stable and active Pt nanoparticle catalyst. New Journal of Chemistry 2021, 45, 11292 -11303.
AMA StyleMartina Fracchia, Paolo Ghigna, Marcello Marelli, Marco Scavini, Alberto Vertova, Sandra Rondinini, Roberto Della Pergola, Alessandro Minguzzi. Molecular cluster route for the facile synthesis of a stable and active Pt nanoparticle catalyst. New Journal of Chemistry. 2021; 45 (25):11292-11303.
Chicago/Turabian StyleMartina Fracchia; Paolo Ghigna; Marcello Marelli; Marco Scavini; Alberto Vertova; Sandra Rondinini; Roberto Della Pergola; Alessandro Minguzzi. 2021. "Molecular cluster route for the facile synthesis of a stable and active Pt nanoparticle catalyst." New Journal of Chemistry 45, no. 25: 11292-11303.
Anton Tsyganok; Paolo Ghigna; Alessandro Minguzzi; Alberto Naldoni; Vadim Murzin; Wolfgang Caliebe; Avner Rothschild; David S. Ellis. Correction to “Operando X-ray Absorption Spectroscopy (XAS) Observation of Photoinduced Oxidation in FeNi (Oxy)hydroxide Overlayers on Hematite (α-Fe2O3) Photoanodes for Solar Water Splitting”. Langmuir 2020, 36, 14155 -14155.
AMA StyleAnton Tsyganok, Paolo Ghigna, Alessandro Minguzzi, Alberto Naldoni, Vadim Murzin, Wolfgang Caliebe, Avner Rothschild, David S. Ellis. Correction to “Operando X-ray Absorption Spectroscopy (XAS) Observation of Photoinduced Oxidation in FeNi (Oxy)hydroxide Overlayers on Hematite (α-Fe2O3) Photoanodes for Solar Water Splitting”. Langmuir. 2020; 36 (46):14155-14155.
Chicago/Turabian StyleAnton Tsyganok; Paolo Ghigna; Alessandro Minguzzi; Alberto Naldoni; Vadim Murzin; Wolfgang Caliebe; Avner Rothschild; David S. Ellis. 2020. "Correction to “Operando X-ray Absorption Spectroscopy (XAS) Observation of Photoinduced Oxidation in FeNi (Oxy)hydroxide Overlayers on Hematite (α-Fe2O3) Photoanodes for Solar Water Splitting”." Langmuir 36, no. 46: 14155-14155.
The activity and the stability of an electrocatalyst are equally important, but the reasons behind deactivation processes still remain unresolved. Achieving a deeper understanding of the process will help to inhibit deactivation and improve revivification protocols.
Alessandro Minguzzi. How to improve the lifetime of an electrocatalyst. Nature Catalysis 2020, 3, 687 -689.
AMA StyleAlessandro Minguzzi. How to improve the lifetime of an electrocatalyst. Nature Catalysis. 2020; 3 (9):687-689.
Chicago/Turabian StyleAlessandro Minguzzi. 2020. "How to improve the lifetime of an electrocatalyst." Nature Catalysis 3, no. 9: 687-689.
A FeNi (oxy)hydroxide co-catalyst overlayer was photoelectrochemically deposited on a thin film hematite (α-Fe2O3) photoanode, leading to a cathodic shift of ~100 mV in the photocurrent onset potential. Operando X-ray absorption spectroscopy (XAS) at the Fe and Ni K-edges was used to study the changes in the overlayer with potential, in dark and under illumination conditions. Potential or illumination only had a minor effect on the Fe oxidation state, suggesting that Fe atoms do not accumulate significant amount of charge over the whole potential range. In contrast, the Ni K-edge spectra showed pronounced dependence on potential in dark and under illumination. The effect of illumination is to shift the onset for the Ni oxidation because of the generated photovoltage, and suggests that holes that are photogenerated in hematite are transferred mainly to the Ni atoms in the overlayer. The increase in the oxidation state of Ni proceeds at potentials corresponding to the redox wave of Ni, which occurs immediately prior to the onset of the oxygen evolution reaction (OER). Linear fitting analysis of the obtained spectra suggests that the overlayer does not have to be fully oxidized to promote oxygen evolution. Cathodic discharge measurements show that the photogenerated charge is stored almost exclusively in the Ni atoms within the volume of the overlayer.
Anton Tsyganok; Paolo Ghigna; Alessandro Minguzzi; Alberto Naldoni; Vadim Murzin; Wolfgang Caliebe; Avner Rothschild; David S. Ellis. Operando X-ray absorption spectroscopy (XAS) observation of photoinduced oxidation in FeNi (oxy)hydroxide overlayers on hematite (α-Fe2O3) photoanodes for solar water splitting. Langmuir 2020, 36, 11564 -11572.
AMA StyleAnton Tsyganok, Paolo Ghigna, Alessandro Minguzzi, Alberto Naldoni, Vadim Murzin, Wolfgang Caliebe, Avner Rothschild, David S. Ellis. Operando X-ray absorption spectroscopy (XAS) observation of photoinduced oxidation in FeNi (oxy)hydroxide overlayers on hematite (α-Fe2O3) photoanodes for solar water splitting. Langmuir. 2020; 36 (39):11564-11572.
Chicago/Turabian StyleAnton Tsyganok; Paolo Ghigna; Alessandro Minguzzi; Alberto Naldoni; Vadim Murzin; Wolfgang Caliebe; Avner Rothschild; David S. Ellis. 2020. "Operando X-ray absorption spectroscopy (XAS) observation of photoinduced oxidation in FeNi (oxy)hydroxide overlayers on hematite (α-Fe2O3) photoanodes for solar water splitting." Langmuir 36, no. 39: 11564-11572.
One of the major drawbacks in Lithium-air batteries is the sluggish kinetics of the oxygen reduction reaction (ORR). In this context, better performances can be achieved by adopting a suitable electrocatalyst, such as MnO2. Herein, we tried to design nano-MnO2 tuning the final ORR electroactivity by tailoring the doping agent (Co or Fe) and its content (2% or 5% molar ratios). Staircase-linear sweep voltammetries (S-LSV) were performed to investigate the nanopowders electrocatalytic behavior in organic solvent (propylene carbonate, PC and 0.15 M LiNO3 as electrolyte). Two percent Co-doped MnO2 revealed to be the best-performing sample in terms of ORR onset shift (of ~130 mV with respect to bare glassy carbon electrode), due to its great lattice defectivity and presence of the highly electroactive γ polymorph (by X-ray diffraction analyses, XRPD and infrared spectroscopy, FTIR). 5% Co together with 2% Fe could also be promising, since they exhibited fewer diffusive limitations, mainly due to their peculiar pore distribution (by Brunauer–Emmett-Teller, BET) that disfavored the cathode clogging. Particularly, a too-high Fe content led to iron segregation (by energy dispersive X-ray spectroscopy, EDX, X-ray photoelectron spectroscopy, XPS and FTIR) provoking a decrease of the electroactive sites, with negative consequences for the ORR.
Eleonora Pargoletti; Annalisa Salvi; Alessia Giordana; Giuseppina Cerrato; Mariangela Longhi; Alessandro Minguzzi; Giuseppe Cappelletti; Alberto Vertova. ORR in Non-Aqueous Solvent for Li-Air Batteries: The Influence of Doped MnO2-Nanoelectrocatalyst. Nanomaterials 2020, 10, 1735 .
AMA StyleEleonora Pargoletti, Annalisa Salvi, Alessia Giordana, Giuseppina Cerrato, Mariangela Longhi, Alessandro Minguzzi, Giuseppe Cappelletti, Alberto Vertova. ORR in Non-Aqueous Solvent for Li-Air Batteries: The Influence of Doped MnO2-Nanoelectrocatalyst. Nanomaterials. 2020; 10 (9):1735.
Chicago/Turabian StyleEleonora Pargoletti; Annalisa Salvi; Alessia Giordana; Giuseppina Cerrato; Mariangela Longhi; Alessandro Minguzzi; Giuseppe Cappelletti; Alberto Vertova. 2020. "ORR in Non-Aqueous Solvent for Li-Air Batteries: The Influence of Doped MnO2-Nanoelectrocatalyst." Nanomaterials 10, no. 9: 1735.
Photoelectrochemical (PEC) water splitting devices using semiconductors and electrocatalysts rely on heterogeneous interfaces that drive charge separation, thus determining potential gradients that dictate the reaction efficiency. The PEC potential of the electrocatalyst depends on the chemical oxidation state of forming elements, which may strongly vary under the photoinduced charge flow. However, element-sensitive, real-time measurements of the oxidation state of the electrocatalyst are not generally possible by using conventional X-ray absorption techniques. Here we show that fixed energy X-ray absorption voltammetry and chronoamperometry, which measures the X-ray absorption coefficient variations along with photocurrent, can follow in real time the redox kinetics of electrocatalysts in operando. In order to demonstrate the validity, we investigate hematite (α-Fe2O3) photoanodes covered with a nickel hydroxide electrocatalyst and show that it is fully oxidized by photogenerated holes to nickel oxyhydroxide with Ni reaching higher oxidation state (NiIV) than that observed under electrocatalytic oxygen evolution in dark conditions. Highly oxidized Ni results from charge accumulation in the overlayer and can be observed only in the case of thick layers (with low PEC performance). On the other hand, the average oxidation state of Ni reaches lower values, under operative conditions, for very thin layers resulting in high PEC activity. We complete our study by presenting PEC activity and impedance spectroscopy analysis using different thickness of electrocatalyst, thus proving a detailed picture of the multiple and complex charge transfer processes occurring at a semiconductor/electrocatalyst junction.
Francesco Malara; Martina Fracchia; Hana Kmentová; Rinaldo Psaro; Alberto Vertova; Danilo Oliveira DE Souza; Giuliana Aquilanti; Luca Olivi; Paolo Ghigna; Alessandro Minguzzi; Alberto Naldoni. Direct Observation of Photoinduced Higher Oxidation States at a Semiconductor/Electrocatalyst Junction. ACS Catalysis 2020, 10, 10476 -10487.
AMA StyleFrancesco Malara, Martina Fracchia, Hana Kmentová, Rinaldo Psaro, Alberto Vertova, Danilo Oliveira DE Souza, Giuliana Aquilanti, Luca Olivi, Paolo Ghigna, Alessandro Minguzzi, Alberto Naldoni. Direct Observation of Photoinduced Higher Oxidation States at a Semiconductor/Electrocatalyst Junction. ACS Catalysis. 2020; 10 (18):10476-10487.
Chicago/Turabian StyleFrancesco Malara; Martina Fracchia; Hana Kmentová; Rinaldo Psaro; Alberto Vertova; Danilo Oliveira DE Souza; Giuliana Aquilanti; Luca Olivi; Paolo Ghigna; Alessandro Minguzzi; Alberto Naldoni. 2020. "Direct Observation of Photoinduced Higher Oxidation States at a Semiconductor/Electrocatalyst Junction." ACS Catalysis 10, no. 18: 10476-10487.
Using density functional theory we studied the influence of group 1 and 11 impurities on the bandgap of Cu2O. Our results show that dopants affect the bandgap through geometric and electronic effects. Geometric effects originate from the compression of adjacent CuO bonds while electronic effects are tightly connected to changes in the ability to delocalize electrons through 2 electron 3 center bonds. Doping with alkali metals disturbs the delocalization network and therefore results in an increased bandgap. The 2 electron 3 center bonding network is restored by Au and Ag dopants or decreased doping concentrations.
Alberto Visibile; Alberto Vertova; Sandra Rondinini; Alessandro Minguzzi; Elisabet Ahlberg; Michael Busch. Strain or Electronic Effects? – The influence of alkali metals on the bandgap of Cu2O. Chemical Physics Letters 2020, 755, 137799 .
AMA StyleAlberto Visibile, Alberto Vertova, Sandra Rondinini, Alessandro Minguzzi, Elisabet Ahlberg, Michael Busch. Strain or Electronic Effects? – The influence of alkali metals on the bandgap of Cu2O. Chemical Physics Letters. 2020; 755 ():137799.
Chicago/Turabian StyleAlberto Visibile; Alberto Vertova; Sandra Rondinini; Alessandro Minguzzi; Elisabet Ahlberg; Michael Busch. 2020. "Strain or Electronic Effects? – The influence of alkali metals on the bandgap of Cu2O." Chemical Physics Letters 755, no. : 137799.
We investigate the co-catalytic activity of PtCu alloy nanoparticles for photocatalytic H2 evolution from methanol-water solutions. To produce the photocatalysts, a few nm-thick Pt-Cu bilayers are deposited on anodic TiO2 nanocavity arrays and converted by solid state dewetting, i.e. a suitable thermal treatment, into bimetallic PtCu nanoparticles. XRD and XPS results prove the formation of PtCu nanoalloys that carry a shell of surface oxides. XANES data support Pt and Cu alloying and indicate the presence of lattice disorder in the PtCu nanoparticles. The PtCu co-catalyst on TiO2 shows a synergistic activity enhancement and a significantly higher activity towards photocatalytic H2 evolution than Pt- or Cu-TiO2. We propose the enhanced activity to be due to Pt-Cu electronic interactions, where Cu increases the electron density on Pt favoring a more efficient electron transfer for H2 evolution. In addition, Cu can further promote the photo-activity by providing additional surface catalytic sites for hydrogen recombination. Remarkably, when increasing the methanol concentration up to 50 vol% in the reaction phase, we observe for PtCu-TiO2 a steeper activity increase compared to Pt-TiO2. A further increase in methanol concentration (up to 80 vol%) causes for Pt-TiO2 a clear activity decay, while PtCu-TiO2 still maintains a high level of activity. This suggests an improved robustness of PtCu nanoalloys against poisoning from methanol oxidation products such as CO.
Fahimeh Shahvaranfard; Paolo Ghigna; Alessandro Minguzzi; Ewa Wierzbicka; Patrik Schmuki; Marco Altomare. Dewetting of PtCu Nanoalloys on TiO2 Nanocavities Provides a Synergistic Photocatalytic Enhancement for Efficient H2 Evolution. ACS Applied Materials & Interfaces 2020, 12, 1 .
AMA StyleFahimeh Shahvaranfard, Paolo Ghigna, Alessandro Minguzzi, Ewa Wierzbicka, Patrik Schmuki, Marco Altomare. Dewetting of PtCu Nanoalloys on TiO2 Nanocavities Provides a Synergistic Photocatalytic Enhancement for Efficient H2 Evolution. ACS Applied Materials & Interfaces. 2020; 12 (34):1.
Chicago/Turabian StyleFahimeh Shahvaranfard; Paolo Ghigna; Alessandro Minguzzi; Ewa Wierzbicka; Patrik Schmuki; Marco Altomare. 2020. "Dewetting of PtCu Nanoalloys on TiO2 Nanocavities Provides a Synergistic Photocatalytic Enhancement for Efficient H2 Evolution." ACS Applied Materials & Interfaces 12, no. 34: 1.
Cu- or Ni-decorated semiconductors represent a potential low-cost alternative to noble-metal-modified photocatalysts. Even more effective are bimetallic NiCu nanoparticles, which can provide a remarkable photocatalytic H2 evolution enhancement compared to single-element Cu or Ni systems. The main concern of such alloyed co-catalysts is their activity with respect to alteration of their elemental composition and oxidation state over reaction time. Ex situ characterization techniques provide controversial interpretations of the co-catalytic role of the individual elements. Hypotheses such as the in situ reduction of “native” Ni or Cu species during photocatalysis, the oxidation of metallic Cu or Ni into oxides or hydroxides, or the formation of p–n junctions or core/shell structures have been proposed. Herein, we present an operando X-ray absorption spectroscopy study of a NiCu–TiO2 system under UV light illumination in ethanol–water solutions, i.e., under photocatalytic H2 evolution conditions. The experimental approach allows for monitoring in real time chemical changes that take place in the co-catalyst under intermittent illumination, i.e., under light on–off cycles. We show that while Ni and Cu are partially oxidized in the as-formed NiCu co-catalyst (air-formed surface oxides or hydroxides) and undergo partial dissolution in the liquid phase under dark conditions, such Ni and Cu oxidized and dissolved species are reduced/redeposited as a bimetallic NiCu phase at the TiO2 surface under illumination. The dissolution/redeposition mechanism is triggered by TiO2 conduction band electrons. We not only prove a UV-light-induced healing of the NiCu co-catalyst but also unambiguously demonstrate that the species responsible for the strongly enhanced photocatalytic H2 evolution of NiCu nanoparticles are the metallic states of Ni and Cu.
Davide Spanu; Alessandro Minguzzi; Sandro Recchia; Fahimeh Shahvardanfard; Ondřej Tomanec; Radek Zboril; Patrik Schmuki; Paolo Ghigna; Marco Altomare. An Operando X-ray Absorption Spectroscopy Study of a NiCu−TiO2 Photocatalyst for H2 Evolution. ACS Catalysis 2020, 10, 8293 -8302.
AMA StyleDavide Spanu, Alessandro Minguzzi, Sandro Recchia, Fahimeh Shahvardanfard, Ondřej Tomanec, Radek Zboril, Patrik Schmuki, Paolo Ghigna, Marco Altomare. An Operando X-ray Absorption Spectroscopy Study of a NiCu−TiO2 Photocatalyst for H2 Evolution. ACS Catalysis. 2020; 10 (15):8293-8302.
Chicago/Turabian StyleDavide Spanu; Alessandro Minguzzi; Sandro Recchia; Fahimeh Shahvardanfard; Ondřej Tomanec; Radek Zboril; Patrik Schmuki; Paolo Ghigna; Marco Altomare. 2020. "An Operando X-ray Absorption Spectroscopy Study of a NiCu−TiO2 Photocatalyst for H2 Evolution." ACS Catalysis 10, no. 15: 8293-8302.
Sn-modification of TiO2 photocatalysts has been recently proposed as a suitable strategy to improve pollutant degradation as well as hydrogen production. In particular, visible light activity could be promoted by doping with Sn2+ species, which are, however, thermally unstable. Co-promotion with N and Sn has been shown to lead to synergistic effects in terms of visible light activity, but the underlying mechanism has, so far, been poorly understood due to the system complexity. Here, the structural, optical, and electronic properties of N,Sn-copromoted, nanostructured TiO2 from sol-gel synthesis were investigated: the Sn/Ti molar content was varied in the 0–20% range and different post-treatments (calcination and low temperature hydrothermal treatment) were adopted in order to promote the sample crystallinity. Depending on the adopted post-treatment, the optical properties present notable differences, which supports a combined role of Sn dopants and N-induced defects in visible light absorption. X-ray absorption spectroscopy at the Ti K-edge and Sn L2,3-edges shed light onto the electronic properties and structure of both Ti and Sn species, evidencing a marked difference at the Sn L2,3-edges between the samples with 20% and 5% Sn/Ti ratio, showing, in the latter case, the presence of tin in a partially reduced state.
Martina Fracchia; Paolo Ghigna; Alessandro Minguzzi; Alberto Vertova; Francesca Turco; Giuseppina Cerrato; Daniela Meroni. Role of Synthetic Parameters on the Structural and Optical Properties of N,Sn-copromoted Nanostructured TiO2: A Combined Ti K-edge and Sn L2,3-edges X-ray Absorption Investigation. Nanomaterials 2020, 10, 1224 .
AMA StyleMartina Fracchia, Paolo Ghigna, Alessandro Minguzzi, Alberto Vertova, Francesca Turco, Giuseppina Cerrato, Daniela Meroni. Role of Synthetic Parameters on the Structural and Optical Properties of N,Sn-copromoted Nanostructured TiO2: A Combined Ti K-edge and Sn L2,3-edges X-ray Absorption Investigation. Nanomaterials. 2020; 10 (6):1224.
Chicago/Turabian StyleMartina Fracchia; Paolo Ghigna; Alessandro Minguzzi; Alberto Vertova; Francesca Turco; Giuseppina Cerrato; Daniela Meroni. 2020. "Role of Synthetic Parameters on the Structural and Optical Properties of N,Sn-copromoted Nanostructured TiO2: A Combined Ti K-edge and Sn L2,3-edges X-ray Absorption Investigation." Nanomaterials 10, no. 6: 1224.
Luca Braglia; Martina Fracchia; Paolo Ghigna; Alessandro Minguzzi; Daniela Meroni; Raju Edla; Matthias Vandichel; Elisabet Ahlberg; Giuseppina Cerrato; Piero Torelli. Understanding Solid–Gas Reaction Mechanisms by Operando Soft X-Ray Absorption Spectroscopy at Ambient Pressure. The Journal of Physical Chemistry C 2020, 124, 14202 -14212.
AMA StyleLuca Braglia, Martina Fracchia, Paolo Ghigna, Alessandro Minguzzi, Daniela Meroni, Raju Edla, Matthias Vandichel, Elisabet Ahlberg, Giuseppina Cerrato, Piero Torelli. Understanding Solid–Gas Reaction Mechanisms by Operando Soft X-Ray Absorption Spectroscopy at Ambient Pressure. The Journal of Physical Chemistry C. 2020; 124 (26):14202-14212.
Chicago/Turabian StyleLuca Braglia; Martina Fracchia; Paolo Ghigna; Alessandro Minguzzi; Daniela Meroni; Raju Edla; Matthias Vandichel; Elisabet Ahlberg; Giuseppina Cerrato; Piero Torelli. 2020. "Understanding Solid–Gas Reaction Mechanisms by Operando Soft X-Ray Absorption Spectroscopy at Ambient Pressure." The Journal of Physical Chemistry C 124, no. 26: 14202-14212.
Alberto Visibile; Tomasz Baran; Sandra Rondinini; Alessandro Minguzzi; Alberto Vertova. Determining the Efficiency of Photoelectrode Materials by Coupling Cavity‐Microelectrode Tips and Scanning Electrochemical Microscopy. ChemElectroChem 2020, 7, 2440 -2447.
AMA StyleAlberto Visibile, Tomasz Baran, Sandra Rondinini, Alessandro Minguzzi, Alberto Vertova. Determining the Efficiency of Photoelectrode Materials by Coupling Cavity‐Microelectrode Tips and Scanning Electrochemical Microscopy. ChemElectroChem. 2020; 7 (11):2440-2447.
Chicago/Turabian StyleAlberto Visibile; Tomasz Baran; Sandra Rondinini; Alessandro Minguzzi; Alberto Vertova. 2020. "Determining the Efficiency of Photoelectrode Materials by Coupling Cavity‐Microelectrode Tips and Scanning Electrochemical Microscopy." ChemElectroChem 7, no. 11: 2440-2447.
Chlorine dioxide (ClO2) has been widely used as a disinfectant in drinking water in the past but its effects on water pipes have not been investigated deeply, mainly due to the difficult experimental set-up required to simulate real-life water pipe conditions. In the present paper, four different kinds of water pipes, two based on plastics, namely random polypropylene (PPR) and polyethylene of raised temperature (PERT/aluminum multilayer), and two made of metals, i.e., copper and galvanized steel, were put in a semi-closed system where ClO2 was dosed continuously. The semi-closed system allowed for the simulation of real ClO2 concentrations in common water distribution systems and to simulate the presence of pipes made with different materials from the source of water to the tap. Results show that ClO2 has a deep effect on all the materials tested (plastics and metals) and that severe damage occurs due to its strong oxidizing power in terms of surface chemical modification of metals and progressive cracking of plastics. These phenomena could in turn become an issue for the health and safety of drinking water due to progressive leakage of degraded products in the water.
Alberto Vertova; Alessandro Miani; Giordano Lesma; Sandra Rondinini; Alessandro Minguzzi; Luigi Falciola; Marco Aldo Ortenzi. Chlorine Dioxide Degradation Issues on Metal and Plastic Water Pipes Tested in Parallel in a Semi-Closed System. International Journal of Environmental Research and Public Health 2019, 16, 4582 .
AMA StyleAlberto Vertova, Alessandro Miani, Giordano Lesma, Sandra Rondinini, Alessandro Minguzzi, Luigi Falciola, Marco Aldo Ortenzi. Chlorine Dioxide Degradation Issues on Metal and Plastic Water Pipes Tested in Parallel in a Semi-Closed System. International Journal of Environmental Research and Public Health. 2019; 16 (22):4582.
Chicago/Turabian StyleAlberto Vertova; Alessandro Miani; Giordano Lesma; Sandra Rondinini; Alessandro Minguzzi; Luigi Falciola; Marco Aldo Ortenzi. 2019. "Chlorine Dioxide Degradation Issues on Metal and Plastic Water Pipes Tested in Parallel in a Semi-Closed System." International Journal of Environmental Research and Public Health 16, no. 22: 4582.
Cu2O is one of the most studied semiconductors for photocathodes in photoelectrochemical water splitting (PEC-WS). Its low stability is counterbalanced by good activity, provided that a suitable underlayer/support is used. While Cu2O is mostly studied on Au underlayers, this paper proposes Cu(0) as a low-cost, easy to prepare and highly efficient alternative. Cu and Cu2O can be electrodeposited from the same bath, thus allowing in principle to tune the final material’s physico-chemical properties with high precision with a scalable method. Electrodes and photoelectrodes are studied by means of electrochemical methods (cyclic voltammetry, Pb underpotential deposition) and by ex-situ X-ray absorption spectroscopy (XAS). While the potential applied for the deposition of Cu has no influence on the bulk structure and on the photocurrent displayed by the semiconductor, it plays a role on the dark currents, making this strategy promising for improving the material’s stability. Au/Cu2O and Cu/Cu2O show similar performances, the latter having clear advantages in view of future use in practical applications. The influence of Cu underlayer thickness was also evaluated in terms of obtained photocurrent.
Alberto Visibile; Martina Fracchia; Tomasz Baran; Alberto Vertova; Paolo Ghigna; Elisabet Ahlberg; Sandra Rondinini; Alessandro Minguzzi. Electrodeposited Cu thin layers as low cost and effective underlayers for Cu2O photocathodes in photoelectrochemical water electrolysis. Journal of Solid State Electrochemistry 2019, 24, 339 -355.
AMA StyleAlberto Visibile, Martina Fracchia, Tomasz Baran, Alberto Vertova, Paolo Ghigna, Elisabet Ahlberg, Sandra Rondinini, Alessandro Minguzzi. Electrodeposited Cu thin layers as low cost and effective underlayers for Cu2O photocathodes in photoelectrochemical water electrolysis. Journal of Solid State Electrochemistry. 2019; 24 (2):339-355.
Chicago/Turabian StyleAlberto Visibile; Martina Fracchia; Tomasz Baran; Alberto Vertova; Paolo Ghigna; Elisabet Ahlberg; Sandra Rondinini; Alessandro Minguzzi. 2019. "Electrodeposited Cu thin layers as low cost and effective underlayers for Cu2O photocathodes in photoelectrochemical water electrolysis." Journal of Solid State Electrochemistry 24, no. 2: 339-355.
Martina Fracchia; Vito Cristino; Alberto Vertova; Sandra Rondinini; Stefano Caramori; Paolo Ghigna; Alessandro Minguzzi. Operando X-ray absorption spectroscopy of WO3 photoanodes. Electrochimica Acta 2019, 320, 1 .
AMA StyleMartina Fracchia, Vito Cristino, Alberto Vertova, Sandra Rondinini, Stefano Caramori, Paolo Ghigna, Alessandro Minguzzi. Operando X-ray absorption spectroscopy of WO3 photoanodes. Electrochimica Acta. 2019; 320 ():1.
Chicago/Turabian StyleMartina Fracchia; Vito Cristino; Alberto Vertova; Sandra Rondinini; Stefano Caramori; Paolo Ghigna; Alessandro Minguzzi. 2019. "Operando X-ray absorption spectroscopy of WO3 photoanodes." Electrochimica Acta 320, no. : 1.
Cu2O has been considered as a candidate material for transparent conducting oxides and photocatalytic water splitting. Both applications require suitably tuned band gaps. Here we explore the influence of compressive and tensile strain on the band gap by means of density functional theory (DFT) modeling. Our results indicate that the band gap decreases under tensile strain while it increases to a maximum under moderate compressive strain and decreases again under extreme compressive strain. This peculiar behavior is rationalized through a detailed analysis of the electronic structure by means of density of states (DOS), density overlap region indicators (DORI), and crystal overlap Hamilton populations (COHP). Contrary to previous studies we do not find any indications that the band gap is determined by d10–d10 interactions. Instead, our analysis clearly shows that both the conduction and the valence band edges are determined by Cu–O antibonding states. The band gap decrease under extreme compressive strain is associated with the appearance of Cu 4sp states in the conduction band region.
Alberto Visibile; Richard Baochang Wang; Alberto Vertova; Sandra Rondinini; Alessandro Minguzzi; Elisabet Ahlberg; Michael Busch. Influence of Strain on the Band Gap of Cu2O. Chemistry of Materials 2019, 31, 4787 -4792.
AMA StyleAlberto Visibile, Richard Baochang Wang, Alberto Vertova, Sandra Rondinini, Alessandro Minguzzi, Elisabet Ahlberg, Michael Busch. Influence of Strain on the Band Gap of Cu2O. Chemistry of Materials. 2019; 31 (13):4787-4792.
Chicago/Turabian StyleAlberto Visibile; Richard Baochang Wang; Alberto Vertova; Sandra Rondinini; Alessandro Minguzzi; Elisabet Ahlberg; Michael Busch. 2019. "Influence of Strain on the Band Gap of Cu2O." Chemistry of Materials 31, no. 13: 4787-4792.
This minireview aims at providing a complete survey concerning the use of X-ray absorption spectroscopy (XAS) for time-resolved studies of electrochemical and photoelectrochemical phenomena. We will see that time resolution can range from the femto-picosecond to the second (or more) scale and that this joins the valuable throughput typical of XAS, which allows for determining the oxidation state of the investigated element, together with its local structure. We will analyze four different techniques that use different approaches to exploit the in real time capabilities of XAS. These are quick-XAS, energy dispersive XAS, pump & probe XAS and fixed-energy X-ray absorption voltammetry. In the conclusions, we will analyze possible future perspectives for these techniques.
Martina Fracchia; Paolo Ghigna; Alberto Vertova; Sandra Rondinini; Alessandro Minguzzi. Time-Resolved X-ray Absorption Spectroscopy in (Photo)Electrochemistry. Surfaces 2018, 1, 138 -150.
AMA StyleMartina Fracchia, Paolo Ghigna, Alberto Vertova, Sandra Rondinini, Alessandro Minguzzi. Time-Resolved X-ray Absorption Spectroscopy in (Photo)Electrochemistry. Surfaces. 2018; 1 (1):138-150.
Chicago/Turabian StyleMartina Fracchia; Paolo Ghigna; Alberto Vertova; Sandra Rondinini; Alessandro Minguzzi. 2018. "Time-Resolved X-ray Absorption Spectroscopy in (Photo)Electrochemistry." Surfaces 1, no. 1: 138-150.
In this paper we propose titanium dioxide modified with cobalt(II) 2-ethylhexanoate ([email protected]) as photoactive material for the efficient visible light driven production of H2O2. We demonstrate that visible light activity can be achieved thanks to a photoinduced electron transfer from the excited complex towards the TiO2 conduction band that corresponds to a cobalt-to-titanium-charge-transfer transition. H2O2 is synthetized by a combination of oxygen reduction and water oxidation, that is possible thanks to the correct band position of [email protected] A mechanism of H2O2 formation is suggested on the basis of experimental evidences. Reactive oxygen intermediates, together with H2O2 are responsible for the photocatalytic degradation of a nonionic surfactant, of methylene blue and of phenol for wastewater treatments. Finally, and quite interestingly, [email protected] can be also used in a photoelectrochemical setup, where it can be adopted both as photoanode and photocatode, and the switching potential corresponds to the redox potential of the adsorbed complex Co(III)/Co(II) couple.
Tomasz Baran; Szymon Wojtyła; Alessandro Minguzzi; Sandra Rondinini; Alberto Vertova. Achieving efficient H2O2 production by a visible-light absorbing, highly stable photosensitized TiO2. Applied Catalysis B: Environmental 2018, 244, 303 -312.
AMA StyleTomasz Baran, Szymon Wojtyła, Alessandro Minguzzi, Sandra Rondinini, Alberto Vertova. Achieving efficient H2O2 production by a visible-light absorbing, highly stable photosensitized TiO2. Applied Catalysis B: Environmental. 2018; 244 ():303-312.
Chicago/Turabian StyleTomasz Baran; Szymon Wojtyła; Alessandro Minguzzi; Sandra Rondinini; Alberto Vertova. 2018. "Achieving efficient H2O2 production by a visible-light absorbing, highly stable photosensitized TiO2." Applied Catalysis B: Environmental 244, no. : 303-312.
Martina Fracchia; Alberto Visibile; Elisabet Ahlberg; Alberto Vertova; Alessandro Minguzzi; Paolo Ghigna; Sandra Rondinini. α- and γ-FeOOH: Stability, Reversibility, and Nature of the Active Phase under Hydrogen Evolution. ACS Applied Energy Materials 2018, 1, 1716 -1725.
AMA StyleMartina Fracchia, Alberto Visibile, Elisabet Ahlberg, Alberto Vertova, Alessandro Minguzzi, Paolo Ghigna, Sandra Rondinini. α- and γ-FeOOH: Stability, Reversibility, and Nature of the Active Phase under Hydrogen Evolution. ACS Applied Energy Materials. 2018; 1 (4):1716-1725.
Chicago/Turabian StyleMartina Fracchia; Alberto Visibile; Elisabet Ahlberg; Alberto Vertova; Alessandro Minguzzi; Paolo Ghigna; Sandra Rondinini. 2018. "α- and γ-FeOOH: Stability, Reversibility, and Nature of the Active Phase under Hydrogen Evolution." ACS Applied Energy Materials 1, no. 4: 1716-1725.