Abstract:

Constructing an efficient and stable heterojunction photocatalyst system is a promising approach to achieve solar-driven water splitting to produce hydrogen. In this work, a novel Mn_0.2Cd_0.8S@CoAl LDH (MCCA) S-scheme heterojunction was successfully prepared through the efficient coupling of Mn_0.2Cd_0.8S nanorods and CoAl LDH nanosheets, employing a physical mixing method. The photoluminescence and photocurrent-time response results demonstrated that the internal electric field of the constructed MCCA S-scheme heterojunction could successfully accelerate charge separation and electron transfer between the Mn_0.2Cd_0.8S interface and the CoAl LDH. Critically, the introduction of the CoAl LDH effectively inhibited the recombination of photogenerated electrons and holes, thereby improving the photocatalytic hydrogen production activity of Mn_0.2Cd_0.8S. A maximum H₂ production of 1177.9 μmol in 5 h was obtained with MCCA-3. This represents a significant improvement compared to what can be achieved with the pure Mn_0.2Cd_0.8S nanorods and CoAl LDH nanosheets individually. This work provides a simple and effective approach for the rational design of S-scheme heterojunction photocatalysts for photocatalytic hydrogen production.

Key words: Mn_0.2Cd_0.8S, CoAl LDH, S-scheme heterojunction, Photocatalytic H₂ production