Promoted Utilization of Charge Carriers in La5Ti2Cu0.9Ag0.1O7S5-Based Photocatalyst Sheets for Efficient Z-Scheme Overall Water Splitting

Abstract

Promoting charge separation and redox reaction kinetics of semiconductor photocatalysts are crucial for enhancing the performance of overall water splitting (OWS). However, it is rather challenging for narrow bandgap photocatalysts due to the severe charge recombination and decreased driving force. The present work demonstrates that efficient utilization of charge carriers on La5Ti2Cu0.9Ag0.1O7S5 (LTCA), an oxysulfide photocatalyst having an absorption edge of 650 nm, can be achieved for Z-scheme OWS via Ga-doping and Rh cocatalyst deposition in a two-step strategy. Ga-doping of LTCA promoted charge separation, and the developed Rh cocatalyst loading over LTCA:Ga created catalytic sites with high dispersion and less aggregation, leading to improved charge transfer and catalytic conversion. An apparent quantum yield of 11.8% at 420 nm was achieved over the assembled cocatalyst-loaded LTCA:Ga|Au|BiVO4:Mo Z-scheme OWS system, which was the highest among OWS systems involving photocatalysts utilizing photons with wavelengths longer than 600 nm.