Oxygen vacancies promoting photoelectrochemical performance of In2O3 nanocubes

Abstract

This work reports a facile method for preparing the new photoactive In2O3 films as well as their implementation in photoelectrochemical (PEC) application. We firstly investigated the relationship between oxygen vacancies (VO) and PEC performance and revealed a rule between them. We found that the optimized In2O3−n sample yielded a photocurrent density up to 3.83 mA/cm2 in 1 M Na2SO4 solution under the solar illumination. It also gave efficiency as high as 75% over 400 nm in the incident-photon-to-current-conversion efficiency (IPCE) spectrum, which is the best value for an In2O3 photoanode reported. Moreover, the PEC performance of these films is enhanced as the VO increased and then decreased with further increasing VO. This two-side effect means VO can favor the photoelectron activation, or act as recombination centers to prohibit the generation of photocurrent. Making highly photoactive In2O3 nanostructures in this work will open up new opportunities in various areas.

Efficient Photoelectrochemical Water Oxidation over Hydrogen‐Reduced Nanoporous BiVO4 with Ni–Bi Electrocatalyst

“…[49] As uitable amount of OVs can optimize the PECp erformance.W eu se am ixed gas of 5% H 2 and 95 %A rt os trengthen the reducinga tmosphere; thus, H-BiVO 4Àx possesses ar elatively highera mount of OVs than A-BiVO 4 ,r esulting in superior photocurrent enhancement. [36] The fact that OVs induced throughh ydrogen treatment enhanced the charge-transportp roperties of BiVO 4 can be experimentally confirmed by comparing photocurrents obtained by back-side andf ront-side light illuminations. It has been shown that BiVO 4 electrodes generate ah igher photocurrent with back illumination than with front illumination, because the back-side illumination generates electron-hole pairs near the back contact, whereas front-side illumination generatese lectron-hole pairs near the electrode surface facing the electrolyte (Figure 4).…”

“…The OVsf unction as shallow donors in BiVO 4 ,facilitating the excitation of electrons by forming an ew energy level in the band gap, [36] resulting in improvede lectrical conductivity and PEC performance. Furthermore, Ni-B i plays ac rucial role in catalyzing PEC water oxidation with BiVO 4 .I ti nhibits the recombination of electron-hole pairs generateda tB iVO 4 by effectively mediating the hole transfer,w herein ac hange in the Ni oxidation state from lower (Ni 2 + andN i 3 + )t oh igher states (Ni 3 + and Ni 4 + )o ccurs.…”

Activation of Ultrathin Films of Hematite for Photoelectrochemical Water Splitting via H2 Treatment

“…The shoulder peak at approximately 532 eV is known to be a result of oxygen vacancies. [19,53,54] Oxygen anions are strongly deshielded because of incomplete ligand shells around neighboring metal cations and exhibit higher XPS binding energies. Deconvolution of the O 1s spectra (see Figure S14) shows that the intensity of the shoulder peak at 532 eV relative to that of the main oxide peak at 530 eV increases from 0.64 for sample A to 0.98 for sample B; this confirms an increased number of oxygen vacancies following hydrogenation.…”

Preferential occupancy of Ca2+ dopant in La1-x Ca x InO3-δ (x = 0–0.20) perovskite: structural and electrical properties

“…4b). This doublet corresponds to In3d 3/2 and In3d 5/2 states and their peaks for LCI-0 (444.8 and 452.5 eV) indicates that In valency is mainly +3 in the LCI-0 system [34,35]. As Ca 2+ is doped in LaInO 3 system (LCI-10), the peak shifting towards lower binding energy (B.E.)…”