High-stability, high-efficiency, and low-cost solar photoelectrochemical (PEC) water splitting has great potential for hydrogen-energy applications. Here, we report on gold/titanium dioxide (Au/TiO₂) nanofiber structures grown directly on a conductive indium tin oxide substrate, and used as photoelectrodes in PEC cells for hydrogen generation. The titanium dioxide nanofibers (TiO₂ NFs) are synthesized using electrospinning, and are surface-modified by the deposition of gold nanoparticles (Au NPs) using a simple photoreduction method. The structure and morphology of the materials were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The surface plasmon resonance (SPR) of the Au NPs was investigated by ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy. The PEC properties of the as-prepared photoelectrodes were measured. The obtained photoconversion efficiency of 0.52% under simulated-sunlight illumination by a 150 W xenon lamp of the Au/TiO₂ NFs structure with 15 min UV irradiation for Au NP deposition was the highest value from comparable structures. Working photoelectrode stability was tested, and the mechanism of the enhanced PEC performance is discussed.

Nanostructures of titanium nitride (TiN) have recently been considered as a new class of plasmonic materials that have been utilized in many solar energy applications. This work presents the synthesis of a novel nanostructure of TiN that has a nanodonut shape from natural ilmenite ore using a low-cost and bulk method. The TiN nanodonuts exhibit strong and spectrally broad localized surface plasmon resonance absorption in the visible region centered at 560 nm, which is well suited for thermoplasmonic applications as a nanoscale heat source. The heat generation is investigated by water evaporation experiments under simulated solar light, demonstrating excellent solar light harvesting performance of the nanodonut structure.

This work reports on the synthesis, characterization, and photocatalytic performance of the TiO₂ inverse opal nanostructure (IP-TiO₂) and the IP-TiO₂ modified by Ag nanoparticles (Ag@IP-TiO₂). The IP-TiO₂ is fabricated using polystyrene spheres as the template and TiCl₄ as the precursor, and the Ag@IP-TiO₂ is realized by photoreduction method. The morphological, structural, and optical properties of the materials are investigated by scanning electron microscopy, X-ray diffraction, ultraviolet–visible (UV-VIS) absorption spectroscopy, and photoluminescence spectroscopy. Their photocatalytic performances are studied by the degradation of rifampicin antibiotic under the visible-light irradiation generated by an LED lamp. The results demonstrate that the IP-TiO₂ is composed of mesopores arranged in the honeycomb structure and strongly absorbs visible light in the wavelength range of 400–500 nm. This facilitates the visible-light catalytic activity of IP-TiO₂, which is further enhanced by the surface modification by Ag nanoparticles. Our studies on the UV-VIS absorption and photoluminescent properties of the materials reveal that the presence of Ag nanoparticles not only enhances the visible-light absorption of IP-TiO₂, but also reduces the recombination of photogenerated electrons and holes. These two factors create a synergic effect that causes the enhanced photocatalytic performance of Ag@IP-TiO₂.

This work explores a new application of titanium nitride nanoparticles (TiN NPs) as efficient photothermal materials in enhancing the greenhouse effect. We demonstrate that a simple greenhouse using TiN NPs-embedded black paint boasts several advantages in solar drying technology, which are indicated by the drying of red chilli. In particular, the greenhouse using TiN NPs significantly improves the drying efficiency, which reduces the mass of red chilli by approximately four times and results in dried chilli with a moisture content of 10% within two days. In addition, by conducting long experiments in various environments, we found that the relative humidity can have a predominant role over the temperature in the solar drying of red chilli and observed that the re-adsorption of moisture can take place during the drying process, which prolongs the drying time and reduces the quality of the dried products.