Transition M etal Nitride‐Bridged All‐Solid‐State Z‐Scheme Heterojunctions for Enhanced Interfacial Charge Transfer and Photocatalysis

Abstract All‐solid‐state Z‐scheme photocatalysts exhibit remarkable potential for enhancing charge transfer dynamics, however, precise regulation of conductive medium distribution at the heterointerface remains challenging. Here, a series of transition metal nitrides (TMNs)‐bridged 1D@2D MO _x @MN _x /ZnIn ₂ S ₄ heterojunctions, including WO ₃ @W ₂ N/ZnIn ₂ S ₄ (WWZ), TiO ₂ @TiN/ZnIn ₂ S ₄ (TTZ), and Co ₃ O ₄ @Co _5.47 N/ZnIn ₂ S ₄ (CCZ) are constructed via an in situ nitridation strategy. Using WWZ as a representative example, the introduction of W ₂ N at the interface of WO ₃ /ZnIn ₂ S ₄ (WZ) heterojunction significantly optimizes charge transfer behavior and accelerates carrier dynamics, as confirmed by in situ irradiated X‐ray photoelectron spectroscopy (ISXPS), in situ Kelvin probe force microscopy (KPFM), Fluorescence lifetime imaging microscope (FLIM), femtosecond transient absorption spectroscopy (fs‐TA), and density functional theory (DFT) calculations. Benefiting from the optimized H* adsorption/desorption process enabled by the strengthened built‐in electric field, the WWZ achieves a hydrogen production rate of 8.9 mmol g ⁻¹ h ⁻¹ . This represents a 20‐fold enhancement compared to pristine ZnIn ₂ S ₄ (ZIS) and a 9.5‐fold improvement over the WO ₃ /ZnIn ₂ S ₄ composite. This work highlights the crucial role of a strong built‐in electric field and interfacial charge transfer capacity in driving photocatalytic activity, offering new insights for the rational design of all‐solid‐state Z‐scheme heterojunctions.