Bandgap-energy-adjustable noble-metal-free MoS2-ZnxCd1−xS for highly efficient H2 production under visible-light

Background Recognized for its high calorific value, clean and non-polluting properties, hydrogen is considered to be one of the most attractive solutions to the impending energy crisis. Photocatalytic water splitting has been widely investigated for its promise to produce hydrogen in a sustainable, environmentally friendly and low-cost approach. In pursuit of high photocatalytic efficiency, multiple strategies haven been explored such as doping, co-catalyst modification and heterojunction construction realizing promising improvements. Methods We synthesized CdS doped with Zn ions and modified with MoS 2 as co-catalyst to form Zn x Cd 1− x S solid solution and MoS 2 -Zn 0.25 Cd 0.75 S heterojunction using a simple one-step hydrothermal method. The synthesized catalyst was used water splitting under visible light irradiation. The structural and morphological characteristics of these materials, along with their photocatalytic mechanisms, were investigated using multiple techniques such as SEM, TEM, XPS, PL, etc. Findings The photocatalyst consisting of 0.9 wt.% MoS 2 -Zn 0.25 Cd 0.75 S achieved a production rate of 6276 μmol h −1  g −1 , which is 17.4 times higher than that of pure CdS and 1.6 times higher than that of Zn 0.25 Cd 0.75 S. The composite also demonstrated a high apparent quantum yield of 11.1 % at 420 nm. The mechanism of the water splitting process, revealed through various techniques, introduces novel pathways for crafting high-efficiency photocatalysts with an internal electron-hole separation heterostructure.