In situ growth of 2D ZnIn2S4 nanosheets on sulfur-doped porous Ti3C2Tx MXene 3D multi-functional architectures for photocatalytic H2 evolution

Abstract

Designing and fabricating photocatalytic systems with multi-functional synergistic mechanisms has become the research topic in photocatalysis. Herein, a unique 3D/2D sulfur doped (S-doped) porous Ti₃C₂T_x@ZnIn₂S₄ heterostructure is rationally constructed by decorating 2D ZnIn₂S₄ nanosheets on 3D S-doped Ti₃C₂T_x architectures via an S sacrificial template and an in situ growth strategy. The 3D/2D S-doped Ti₃C₂T_x@ZnIn₂S₄ heterostructure possesses hierarchically porous scaffold configurations, a 3D interconnected conductive network, and abundant surface-terminated active groups, which greatly shorten the electron transport pathway and expose more catalytic active sites. Furthermore, according to experimental analysis and theoretical calculations, the S dopant synergistically participates in modulating electrons, triggering the unsaturated sites, and optimizing *H adsorption energy (ΔG_H*). More importantly, the intimate Ti–S interface establishes an electron directional transport channel, thus achieving valid and stable interfacial electron transport. Consequently, the optimal heterostructure photocatalyst exhibits a high photocatalytic H₂ evolution rate of 3.058 mmol g⁻¹ h⁻¹, which is 3.8 times higher than that of the pure ZnIn₂S₄ nanosheet. Additionally, such a robust 3D architecture ensures the stability of photocatalytic H₂ evolution. This work heralds a new pathway for the construction of versatile and high-performance 3D MXene-based photocatalysts.