Ternary CdS@MoS₂-Co₃O₄ Multiheterojunction Photocatalyst for Boosting Photocatalytic H₂ Evolution

Turning the carrier dynamics in heterojunction photocatalysts is a direct and effective strategy for improving the solar energy conversion efficiency of photocatalysts. Herein, we report a ternary CdS@MoS₂-Co₃O₄ multiheterojunction photocatalyst consisting of the p-n junction of MoS₂-Co₃O₄ and the type-I junction of CdS@MoS₂, wherein MoS₂ located at the frontier between CdS and Co₃O₄ acts as an intermediate bridge. The type-I junction allows the directional transfer of photoinduced charge from CdS to MoS₂, suppressing the photocorrosion of CdS. Notably, the single-particle photoluminescence technique demonstrates the sequential one-direction hole transfer from MoS₂ to Co₃O₄ aroused by the p-n junction, resulting in a long-lifetime charge separation in the carrier lifetime (54-58 ns). Compared to the bare CdS and type-I CdS@MoS₂, the CdS@MoS₂-Co₃O₄ photocatalyst affords a 347-fold and 3.5-fold enhancement of the H₂ evolution rate, a quantum efficiency of 28.6% at 450 nm, and a 20 h of long-term stability. This work provides a new understanding of the rational regulation of the charge-transfer mechanism of type-I systems by constructing multiheterojunction photocatalysts.