Photovoltaic-enhanced water splitting properties of low-temperature-synthesized BiVO4 photoanode films

The fabrication of photoelectrodes on indium tin oxide (ITO) glass at low temperatures poses a significant challenge due to the inherent instability of ITO at reduced temperatures, while the inexpensive production of high-functionality photoanode technology is a critical determinant facilitating large-scale photovoltaic conversion in water splitting. In this work, highly efficient BiVO4 (BVO) photoanodes with different thicknesses were grown on ITO glass at a low temperature by the sol-gel spin coating method. Pure BVO photoanode, enriched with nanostructures, exhibits a current density of 2.25 mA cm-2 (@1.23 V vs. RHE) under AM-1.5G illumination. The photovoltaic effect induces a continual oxygen evolution reaction at zero bias voltage on the photoanode, resulting in a photocurrent density of 0.04 mA cm-2 at zero bias. This study not only evaluates the feasibility of the large-scale fabrication of a photoanode from economic considerations but also presents potential for water splitting properties of the BVO photoanode.

The application of FTO-Cu2O/Ag3PO4 heterojunction in the photoelectrochemical degradation of emerging pharmaceutical pollutant under visible light irradiation

We report the photoelectrochemical application of a visible light active FTO-Cu₂O/Ag₃PO₄ photoanode for the abatement of sulfamethoxazole in water. The as-synthesised photoanodes were characterised using XRD, field emission SEM, EDX, diffuse reflectance UV-vis, impedance spectroscopy and chronoamperometry. The results obtained confirmed a successful formation of p-n heterojunction at the Cu₂O/Ag₃PO₄ interface. The highest photocurrent response of 0.62 mAcm^-2 was obtained for the composite photoanode which was four times higher than pure Cu₂O and about three times higher than pristine Ag₃PO₄. The photoanode gave 67% removal efficiency within 2 h upon its photoelectrochemical application in the degradation of sulfamethoxazole with 1.5 V bias potential at pH 6.2. The FTO-Cu₂O/Ag₃PO₄ electrode was also applied in the treatment of a cocktail of synthetic organics containing sulfamethoxazole and orange II dye. The photogenerated holes was found to be the major oxidant and the photoanodes was stable and reusable.

Mulberry-like BiVO4 architectures: synthesis, characterization and their application in photocatalysis

Mulberry-like BiVO₄ architectures were prepared by a facile solvothermal route. The obtained architectures showed enhanced light absorption, high photocatalytic properties, good stability and reusability.

Free-Standing Electrospun W-Doped BiVO4 Porous Nanotubes for the Efficient Photoelectrochemical Water Oxidation

While bismuth vanadate (BiVO₄) has emerged as a promising photoanode in solar water splitting, it still suffers from poor electron-hole separation and electron transport properties. Therefore, the development of BiVO₄ nanomaterials that enable performing high charge transfer rate at the interface and lowering charge recombination is urgent needed. Herein, cobalt borate (Co-B) nanoparticle arrays anchored on electrospun W-doped BiVO₄ porous nanotubes (BiV_0.97W_0.03O₄) was prepared for photoelectrochemical (PEC) water oxidation. One-dimensional, free-standing and porousBiV_0.97W_0.03O₄/Co-B nanotubes was synthesized through electrospun and electrodeposition process. BiV_0.97W_0.03O₄/Co-B arrays exhibit a unique self-supporting core-shell structure with rough porous surface, providing abundant conductive cofactor (W) and electrochemically active sites (Co) exposed to the electrolyte. When applied to PEC water oxidation. BiV_0.97W_0.03O₄/Co-B modified FTO electrode displays high incident photon-to-current conversion efficiency (IPCE) of 33% at 405 nm (at 1.23 V vs. RHE) and its photocurrent density is about 4 times to the pristine nanotube. The higher PEC water oxidation properties of BiV_0.97W_0.03O₄/Co-B porous nanotubes may be attributed to the effectively suppress the electron-hole recombination at electrolyte interface due to its self-supporting core-shell structure, the high electrocatalytic activity of Co and the good electrical conductivity of BiV_0.97W_0.03O₄ arrays. This work offers a simple preparation strategy for the integrated Co-B nanoparticle with BiV_0.97W_0.03O₄ nanotube, demonstrating the synergistic effect of co-catalysts for PEC water oxidation.

Ag2O-decorated electrospun BiVO4 nanofibers with enhanced photocatalytic performance

Semiconductor photocatalysts are emerging as tools for pollutant degradation in industrial wastewater, air purification, antibacterial applications, etc. due to their use of visible light, which is abundant in sunlight. Here, we report a new type of p–n junction Ag₂O/BiVO₄ heterogeneous nanostructured photocatalyst with enhanced photocatalytic performance. P-type Ag₂O nanoparticles were in situ reduced and assembled on the surface of electrospun BiVO₄ nanofibers using ultraviolet (UV) irradiation; this process hindered the recombination of localized photogenerated electron–hole pairs, and hence resulted in the enhanced photocatalytic activity of the BiVO₄/Ag₂O nanocomposites. The photocatalytic activities of the obtained BiVO₄ and BiVO₄/Ag₂O nanocomposites were assessed by measuring the degradation of rhodamine B (RhB) under visible light. The 10 wt% Ag₂O/BiVO₄ sample yielded the optimum degradation of RhB (98.47%), much higher than that yielded by pure BiVO₄ nanofibers (64.67%). No obvious change in the XRD pattern of an Ag₂O/BiVO₄ sample occurred as a result of its use in the photocatalytic reaction, indicating its excellent stability. The high photocatalytic performance observed was attributed to the large surface-to-volume ratio of the essentially one-dimensional electrospun BiVO₄ nanofibers and to the in situ growth of p-type Ag₂O on the surface of the n-type BiVO₄ nanofibers.

Ag₂O doped electrospun BiVO₄ nanofibers with p–n junction heterogeneous structures show enhanced photocatalytic activity under visible light (photocatalytic efficiency: 98.47% within 100 min) and good cycling stability.

Efficient electrospinning fabrication and the underlying formation mechanism of one-dimensional monoclinic Li2FeSiO4 nanofibers

Monoclinic Li₂FeSiO₄ nanofibers were first smartly fabricated via a controllable electrospinning technique along with subsequent calcination in an air/O₂ atmosphere in sequence, and the involved formation mechanism was reasonably proposed.

Controlled Synthesis of CuS/TiO2 Heterostructured Nanocomposites for Enhanced Photocatalytic Hydrogen Generation through Water Splitting

Photocatalytic hydrogen (H₂) generation through water splitting has attracted substantial attention as a clean and renewable energy generation process that has enormous potential in converting solar-to-chemical energy using suitable photocatalysts. The major bottleneck in the development of semiconductor-based photocatalysts lies in poor light absorption and fast recombination of photogenerated electron-hole pairs. Herein we report the synthesis of CuS/TiO₂ heterostructured nanocomposites with varied TiO₂ contents via simple hydrothermal and solution-based process. The morphology, crystal structure, composition, and optical properties of the as-synthesized CuS/TiO₂ hybrids are evaluated in detail. Controlling the CuS/TiO₂ ratio to an optimum value leads to the highest photocatalytic H₂ production rate of 1262 μmol h^-1 g^-1, which is 9.7 and 9.3 times higher than that of pristine TiO₂ nanospindles and CuS nanoflakes under irradiation, respectively. The enhancement in the H₂ evolution rate is attributed to increased light absorption and efficient charge separation with an optimum CuS coverage on TiO₂. The photoluminescence and photoelectrochemical measurements further confirm the efficient separation of charge carriers in the CuS/TiO₂ hybrid. The mechanism and synergistic role of CuS and TiO₂ semiconductors for enhanced photoactivity is further delineated.