CoAl LDH in-situ derived CoAlP coupling with Ni2P form S-scheme heterojunction for efficient hydrogen evolution

Accelerating the separation and migration efficiency of photogenerated charge carriers and creating abundant active sites are the keys to the excellent H-2 production performance of photocatalysts. In this work, two strategies, the construction of S-scheme heterojunction and the introduction of active P species, were carried out based on polyhedral Ni-MOF-74 and layered CoAl LDH, in order to accelerate the separation and migration of electronhole pairs as well as create rich active sites for more improved photocatalytic H-2 evolution performance. First, a delicate Ni-MOF-74/CoAl LDH S-scheme heterojunction was constructed, and then Ni-MOF-74/CoAl LDH was converted to CoAlP/Ni2P S-scheme heterojunction. That is, the active P species was introduced based on the presence of Sscheme heterojunction. More importantly, Ni-MOF-74/CoAl LDH S-scheme heterojunction photocatalyst exhibits visible improvement in H-2 generation rate in comparison with single Ni-MOF-74 and CoAl LDH, which is attributed to the formation of S-scheme heterojunction undoubtedly. Further, CoAlP/Ni2P S-scheme heterojunction shows more improved H-2 production performance than Ni-MOF-74/CoAl LDH, suggesting that P-modification is a high-efficiency means for enriching surface active sites and implementing the conversion of S-scheme heterojunction to S-scheme heterojunction. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.