An unexpected broad-spectral absorbed lanthanum oxychloride and lanthanum titanate heterostructure promoted photoelectrocatalytic hydrogen evolution

Abstract

Photoelectrochemical (PEC) water splitting, an attractive approach to convert and storage solar energy into high value-added chemicals, is limited by the narrow light harvesting, low charge-separation efficiency and sluggish surface reaction kinetics of photoanodes. Here, a novel photoanode based on lanthanum oxychloride and lanthanum titanate (LTO/LaOCl@N-C) microsphere heterostructure derived from lanthanide coordination polymers is reported. Benefiting from the well-defined nanostructure and carbon-nitrogen co-doping, the obtained heterostructure exhibited unexpected broad-spectral absorption from 200 to 800 nm, remarkably increased charge-carrier separation and inhibited electron-hole recombination, thereby leading to a high performance of photoelectrocatalytic hydrogen evolution with a rate of 26.43 μmol·h−1·cm−2 (37.18 mmol·g−1·h−1/37.18 μmol·mg−1·h−1) under the simulated solar irradiation recorded at 0.7 V vs. RHE, which surpasses the previous studies of LTO-based composites, even comparable to some state-of-the-art noble-metal free photoanodes. This work could open new insight into rationally designing lanthanum-based photoelectrocatalysts for water splitting.