An in-situ NH4+-etched strategy for anchoring atomic Mo site on ZnIn2S4 hierarchical nanotubes for superior hydrogen photocatalysis

Atomic sites co-catalyst (ASC) on photocatalytic materials possesses an attractive prospect to promote charge carrier separation and tune surface reaction kinetics, yet the synthesis of earth-abundant ASC under low temperature remains a great challenge. Here, a novel in-situ NH 4 + -etched strategy to anchor atomic Mo sites on ZnIn 2 S 4 hierarchical nanotubes (HNTs) with abundant mesopores under mild conditions for promoting charge carrier separation and enhancing light multi-reflections is developed for efficient photocatalytic H 2 evolution. Density functional theory calculations and linear sweep voltammetry demonstrate that the well-defined Mo-S 2 O 1 sites with distinctive coordination configuration and electronic property contribute to the enhanced separation of photo-generated charge carriers and reduced Gibbs free energy for H 2 evolution. Consequently, the well-defined MoSA-ZIS HNTs present an excellent photocatalytic activity with a rate of 29.9 µmol h −1 (5.98 mmol g −1 h −1 ), which is 7.3 times higher than that of ZnIn 2 S 4 nanosheets (NSs), to be among the best ZnIn 2 S 4 -based photocatalysts. The present strategy breaks the high-temperature limitation of conventional top-down thermal dissociation/emitting approach for anchoring non-noble metal atomic sites on catalyst support.