Nanostructured WO₃/BiVO₄Heterojunction Films for Efficient Photoelectrochemical Water Splitting

Abstract

We report on a novel heterojunction WO(3)/BiVO(4) photoanode for photoelectrochemical water splitting. The heterojunction films are prepared by solvothermal deposition of a WO(3) nanorod-array film onto fluorine-doped tin oxide (FTO) coated glass, with subsequent deposition of a low bandgap, 2.4 eV, visible light responding BiVO(4) layer by spin-coating. The heterojunction structure offers enhanced photoconversion efficiency and increased photocorrosion stability. Compared to planar WO(3)/BiVO(4) heterojunction films, the nanorod-array films show significantly improved photoelectrochemical properties due, we believe, to the high surface area and improved separation of the photogenerated charge at the WO(3)/BiVO(4) interface. Synthesis details are discussed, with film morphologies and structures characterized by field emission scanning electron microscopy and X-ray diffraction.

Promoting charge carrier utilization by integrating layered double hydroxide nanosheet arrays with porous BiVO4 photoanode for efficient photoelectrochemical water splitting

“…3b). These results suggest that the back-side illumination is an efficient way to suppress the absorption of NiFe-LDH which can compete with the BiVO4, as discussed in previous reports [13,[40][41][42].…”

“…The adjustable species and ratios of metal ions in LDHs make the LDHs the promising candidates as OECs in PEC devices. Considering that the outstanding performance can be achieved through using un-doped porous BiVO4 film as only photon absorber and nanostructured LDHs as OECs, further improvement of the PEC cell efficiency is expected when various strategies of tuning the compositions [16] or forming heterojunctions [29,40,60] and tandem cells [18,46] are used to enhance absorption and photogenerated carriers' separation of semiconductors. Therefore, our work could provide a new strategy to fabricate composite photoanodes effectively promoting charge utilization and the surface reaction kinetics for PEC water splitting and other solar-to-fuel energy conversion applications.…”

Improving O2 production of WO3 photoanodes with IrO2 in acidic aqueous electrolyte

“…Tungsten trioxide, WO 3 , an earth-abundant, oxidatively stable semiconductor, is one such material that could fulfill the role of photoanode. [14][15][16][17][18][19][20][21][22][23][24] In most deposition methods, the presence of oxygen vacancies serve as shallow electron donors and naturally dope the WO 3 n-type. 25 Its band gap of 2.6 eV is higher than ideal for the large band gap absorber in a tandem cell.…”

Synthesis and characterization of tungstite (WO3·H2O) nanoleaves and nanoribbons

“…A simple heat-treatment of tungstite (WO 3 .H 2 O) allows for the phase transformation to tungsten oxide (WO 3 ), an important class of n-type semiconductors with a tunable band gap of 2.5-2.8 eV [16]. Moreover, its high chemical stability, low production costs and non-toxicity have recently generated significant interests for a wide variety of applications in microelectronics and optoelectronics [17][18], super-hydrophilic thin films [15], dye-sensitized solar cells [19], colloidal quantum dot LEDs [20], photocatalysis [21] and photoelectrocatalysis [22], water splitting photocatalyst as main catalyst [23][24][25][26][27][28][29][30][31][32][33][34]. Environmental applications can also benefit from WO 3 as a visible light photocatalyst to generate OH radicals for bacteria destruction [35] and photocatalytic reduction of CO 2 into hydrocarbon fuels [36].…”