Interfacing CdS particles on Ni foam as a three-dimensional monolithic photocatalyst for efficient visible-light-driven H2 evolution

Abstract

Solar photocatalytic water splitting using particulate semiconductors has been valued as a potentially scalable way for the production of clean H2 energy, yet the performances of the powder-suspension systems are constrained by insufficient utilization of light energy and tedious recycling of photocatalyst particles. Here, we present a high-performance photocatalytic H2 evolution using a visible-light-driven CdS-based monolithic photocatalyst with three-dimensional (3D) heterostructure. The monolithic photocatalyst is fabricated by firmly growing CdS microspheres on a Ni(OH)2 nanosheet-modified Ni foam (NF) (denoted as CdS-NiSx/NF) via a simple hydrothermal process. The structure and component synergy endows the monolithic CdS-NiSx/NF photocatalyst advantageous features including high-density CdS microspheres for visible light harvesting, multiple heterojunction interfaces for efficient electron-hole separation, and abundant interfacial NiSx active sites for efficient H2 evolution reaction (HER). Upon visible light irradiation, the monolithic CdS-NiSx/NF photocatalyst exhibits an outstanding photocatalytic H2 evolution activity with an enhanced rate of 6.2 mmol·h−1 g−1CdS, which is 6 times higher than that of the suspended CdS powder. In addition, the structural integrity of the CdS-NiSx/NF enables a good stability for H2 evolution over a 30 h reaction. This monolithic photocatalyst is scalable in preparation and compatible for device fabrication, which offers great potentials for applications in solar cells, photoelectrocatalysis, and electrocatalysis.