Sun X, Lan Z, Wang M, Geng Q, Lv X, Li M. Multifunctional Role of Ag-Substitution in Enhancing the Photoelectrochemical Properties of LaFeO
3 Photocathodes.
CHEMSUSCHEM 2023;
16:e202300645. [PMID:
37438975 DOI:
10.1002/cssc.202300645]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/17/2023] [Accepted: 07/10/2023] [Indexed: 07/14/2023]
Abstract
Earth-abundant LaFeO3 is a promising p-type semiconductor for photoelectrochemical cells due to its stable photoresponses, high photovoltages and appropriate band alignments, but the photoelectrochemical properties of LaFeO3 , especially the incident-photon-to-current conversion efficiency, need to be further improved. Herein, we propose to partially substitute La3+ of LaFeO3 with Ag+ to enhance the photoelectrochemical performance of LaFeO3 . The combined experimental and computational studies show that Ag-substitution improves surface charge transfer kinetics through introducing active electronic states and increasing electrochemically active surface areas. Furthermore, Ag-substitution decreases grain boundary number and increases majority carrier density, which promotes bulk charge transports. Ag-substitution also reduces the bandgap energy, increasing the flux of carriers involved in photoelectrochemical reactions. As a result, after 8 % Ag-substitution, the photocurrent density of LaFeO3 is enhanced by more than 6 times (-0.64 mA cm-2 at 0.5 V vs RHE) in the presence of oxygen, which is the highest photocurrent gain compared with other cation substitution or doping. The corresponding photocurrent onset potential also demonstrates a positive shift of 30 mV. This work highlights the versatile effects of Ag-substitution on the photoelectrochemical properties of LaFeO3 , which can provide useful insights into the mechanism of enhanced photoelectrochemical performance by doping or substitution.
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