Tuning Charge Transfer between Size-Controlled Pt Cluster and N Vacancy Engineered Ultrathin G-C3n4 for Efficient Photocatalytic Hydrogen Evolution

Abstract

Rational design and development of metal-cluster co-catalysts with regulated charge transfer interface is an effective strategy to fabricate highly active photocatalysis. Here, Pt clusters are elaborately incorporated onto N vacancy engineered ultrathin g-C3N4 (vUCN) by a facile photo-deposition method. The targeted vUCN-300Pt with cluster size of 1.1 nm and dispersion density of 104 μg m-2 exhibits an optimal photocatalytic rate of 862.4 μmol h-1 g-1, which is approximate 40 times and 5.3 times higher than that of pristine g-C3N4 and vUCN. The inherent reason for the superior property lies in the promoted light absorption ability and decreased proton reduction barrier under the collaborative optimization of the band-gap structure by Pt cluster and vUCN. Additionally, an innovative electron transfer pathway is established,in which electron are initially trapped at N vacancy site and subsequently directed towards the neighboring Pt cluster. Afterwards the Pt site with reduced Gibbs free energy could serve as a highly active medium for combining H* and the transferred electron to achieve efficient H2 evolution. The relevance of these findings provides useful guideline for tuning the reactive metal-support interaction (RMSI) between Pt cluster and g-C3N4-based catalysts.

Keywords: Pt cluster, N vacancy engineered ultrathin g-C3N4, band-gap structure, rapid electron transfer