Effect of Surface Passivation on Photoelectrochemical Water Splitting Performance of WO3 Vertical Plate-Like Films

Abstract

WO3 vertical plate-like arrays provide a direct pathway for charge transport, and thus hold great potential as working electrodes for photoelectrochemical (PEC) water splitting. However, surface recombination due to surface defects hinders the performance improvement. In this work, WO3 vertical plate-like arrays films with HfO2 passivation layer were fabricated via a simple dip-coating method. In the images of transmission electron microscope, a fluffy layer and some small sphere particles existed on the surface of WO3 plate. X-ray photoelectron spectroscopy (XPS) showed a higher concentration of Hf element than the result of energy-dispersive X-ray spectroscopy (EDX), which means that HfO2 is rich on the surface of WO3 plates. A higher photocurrent under visible light irradiation was gained with surface passivation. Meanwhile, the results of intensity modulated photocurrent spectrum (IMPS) and incident photon to current conversion efficiency (IPCE) indicate that HfO2 passivation layer, acting as a barrier for the interfacial recombination, is responsible for the improved photoelectrochemical performance of WO3 vertical plate-like arrays film.

In situ charge carrier dynamics of semiconductor nanostructures for advanced photoelectrochemical and photocatalytic applications

“…However, the fast charge recombination at the surface defect sites (W 5+ and surface states) hinders the overall PEC performance. Several strategies have been proposed to address this issue, such as hydrogen treatment [83,84], co-catalyst deposition [85][86][87] and passivation layer introduction [88,89]. Kim et al reported an efficient surface passivation approach for decreasing the photoelectron trapping event for WO 3 using an Al 2 O 3 overlayer [44].…”

Dry Hydrogen Production in a Tandem Critical Raw Material-Free Water Photoelectrolysis Cell Using a Hydrophobic Gas-Diffusion Backing Layer

“…The existence of several concerns related to the increasing energy demand and the related environmental crisis [1][2][3][4][5][6] indicates the need to identify innovative, effective and low cost solutions. Photoelectrochemical water splitting (PWS) [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] is recognised as a promising strategy and it attracts particular interest for storing solar energy into the chemical bonds of hydrogen as fuel [26][27][28], which can be further utilised in fuel cells [29][30][31][32][33][34], internal combustion engines and to progressively decarbonize industrial processes [35][36][37][38][39].…”

Enhanced photoelectrochemical performance of tungsten oxide film by bifunctional Au nanoparticles

“…[6][7][8][9][10][11] Herein, tungsten oxide (WO 3 ) has been seen as a promising photoelectrode material for the PEC water oxidation system due to its 2.6-2.8 eV band gap and photostability in water. [12][13][14][15] Furthermore, WO 3 can also provide enough overpotential for the crucial half reaction of oxygen evolution due to its favorable valence position (which is approximately 3 V versus NHE). Recently, Ma and coworkers reported that a mesoporous WO 3 photoanode with a dual oxygen and tungsten vacanciescontaining overlayer could greatly enhance the PEC activity for water oxidation, which was attributed to alleviating charge recombination at the electrode/electrolyte interface.…”