CuGaS₂–ZnS p–n nanoheterostructures: a promising visible light photo-catalyst for water-splitting hydrogen production

Abstract

In this work, novel CuGaS₂-ZnS p-n type semiconductor nanoheterostructures were synthesized by a solution route, and demonstrated experimentally to be a very promising visible light active photo-catalyst for water-splitting hydrogen production. The construction of CuGaS₂-ZnS heterostructures follows a multi-step strategy, employing Cu_1.94S nanocrystals first as catalytic assistants for the hetero-growth of ZnS on their surfaces, and then as sacrificial seeds for the formation of CuGaS₂. Excitingly, attributed to the efficient charge separation introduced by the p-n heterojunctions, the hydrogen production ability of the CuGaS₂-ZnS nanoheterostructures under visible light irradiation is 15 times higher than that of the CuGaS₂ component, and comparable to that of the CdS nanophase which is currently regarded as one of the most active visible photo-catalysts for hydrogen generation.