Spatially Isolated Noble-Metal-Free Redox Cocatalysts on CdS Nanorods for Increased Photocatalytic Hydrogen Generation

Abstract

Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photo-catalytic hydrogen generation. However, the effective preparation of such photocatalysts has proven challenging. Herein, we report the facile synthesis of a novel noble-metal-free CdS/MoS2/CoPi ternary photocatalyst via a visible light-induced synthesis route, in which MoS2 reduction cocatalysts were precisely grown on the two terminals of CdS nanorods, while CoPi oxidation cocatalysts were preferentially anchored onto the sidewalls of CdS nanorods. Such spatially isolated MoS2 and CoPi redox cocatalysts endow CdS nanorods with a rapid charge separation, which enhances their hydrogen generation activity. The CdS/MoS2/CoPi photocatalyst with optimized CoPi amount achieves the highest H2 generation rate of 206 μmol/h, which is 21 and 2 times higher than that achieved by using CdS alone (9.7 μmol/h) and CdS/MoS2 (105 μmol/h), respectively. The present work highlights the effectiveness of the spatial isolation of reduction and oxidation sites for efficient charge separation and thereby provides a promising strategy for the preparation of highly active photocatalysts.