Incorporating Ag Nanocrystals with LaFeO3 Photocathodes Towards Greatly Enhanced Photoelectrocatalytic Properties

This study focuses on enhancing the photoelectrocatalytic (PEC) performance of LaFeO3 photocathodes by incorporating Ag nanocrystals. LaFeO3, a perovskite-type metal oxide semiconductor, has potential in PEC water splitting but suffers from fast charge carrier recombination. Ag nanoparticles are introduced due to their surface plasmon resonance (SPR) property and ability to form Schottky junctions with LaFeO3. A series of Ag/LaFeO3 materials are prepared using the molten salt method for LaFeO3 synthesis and the direct reduction method for Ag loading. The results show that Ag nanoparticles are uniformly dispersed on LaFeO3. The 3 mol% Ag/LaFeO3 photocathode demonstrates a remarkable ninefold increase in photocurrent density (15 mA·cm−2 at −0.2 V vs. RHE) compared to pure LaFeO3 (1.7 mA·cm−2). The band gap of LaFeO3 is reduced from 2.07 eV to 1.92 eV with 3 mol% Ag loading, and the charge transfer impedance is reduced by 77%, while the carrier concentration increases by 2.3 times. The novelty of this work lies in the comprehensive investigation of the interaction mechanisms between Ag nanoparticles and LaFeO3, which lead to enhanced light absorption, improved charge separation, and increased electrochemical activity. The optimized Ag loading not only improves the photocatalytic efficiency but also enhances the stability of the photocathode. This work provides valuable insights into the interaction between Ag and LaFeO3, and offers experimental and theoretical support for developing efficient photocatalytic materials for PEC water splitting.