Defect-engineered MXene monolith enabling interfacial photothermal catalysis for high-yield solar hydrogen generation

Solar-driven formic acid dehydrogenation shows great potential for sustainable hydrogen utilization. Nevertheless, photothermal catalytic materials that are essential to dehydrogenation not only exhibit limited solar absorption and large heat loss but also heavily rely on noble metals, limiting efficient and low-cost hydrogen generation. Here, we report a porous MXene monolith that enables interfacial heat localization and propose a defect-engineering strategy for MXenes to realize the coordinated regulation of photothermal property and catalytic activity, which is further evidenced by density functional theory calculations. As a result, this design achieves a hydrogen generation rate of 401 mmol g−1 h−1 with an H2 selectivity of 100% and catalytic stability over 45 h of operation, significantly surpassing many state-of-the-art, Pd-based noble metal materials. The work provides new insight into the design of photothermal catalytic MXenes and may open a new application toward solar hydrogen generation.