Open AccessPhotoelectrochemical Behavior and Computational Insights for Pristine and Doped NdFeO3 Thin-Film Photocathodes
Author(s) -
Javier Quiñonero,
Francisco-Javier Ferrández-Pastor,
J.M. Orts,
Roberto Gómez
Publication year - 2021
Publication title -
acs applied materials and interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.535
H-Index - 228
eISSN - 1944-8252
pISSN - 1944-8244
DOI - 10.1021/acsami.0c21792
Subject(s) - photocathode , materials science , photocurrent , dopant , doping , water splitting , thin film , ternary operation , hydrogen , photoelectrochemical cell , optoelectronics , oxygen evolution , reversible hydrogen electrode , nanotechnology , electrochemistry , electrode , photocatalysis , catalysis , electrolyte , electron , chemistry , computer science , biochemistry , quantum mechanics , programming language , physics , organic chemistry , reference electrode
Among the different strategies that are being developed to solve the current energy challenge, harvesting energy directly from sunlight through a tandem photoelectrochemical cell (water splitting) is most attractive. Its implementation requires the development of stable and efficient photocathodes, NdFeO 3 being a suitable candidate among ternary oxides. In this study, transparent NdFeO 3 thin-film photocathodes have been successfully prepared by a citric acid-based sol-gel procedure, followed by thermal treatment in air at 640 °C. These electrodes show photocurrents for both the hydrogen evolution and oxygen reduction reactions. Doping with Mg 2+ and Zn 2+ has been observed to significantly enhance the photoelectrocatalytic performance of NdFeO 3 toward oxygen reduction. Magnesium is slightly more efficient as a dopant than Zn, leading to a multiplication of the photocurrent by a factor of 4-5 for a doping level of 5 at % (with respect to iron atoms). This same trend is observed for hydrogen evolution. The beneficial effect of doping is primarily attributed to an increase in the density and a change in the nature of the majority charge carriers. DFT calculations help to rationalize the behavior of NdFeO 3 by pointing to the importance of nanostructuring and doping. All in all, NdFeO 3 has the potential to be used as a photocathode in photoelectrochemical applications, although efforts should be directed to limit surface recombination.