Unveiling the Dynamic Electronic Structure of CuZn Catalysts for Solar-driven CO2 Reduction, Applied Catalysis B: Environment and Energy 395,126897(2026)
Ruspika Sundaresan, Chung Sheng Tseng, Tai Ying Lai, You-Chiuan Chu, Guan-Bo Wang, Feng-Ze Tian, Chia-Shuo Hsu, Ching-Wei Tung*, Hao Ming Chen*
2026/08/17
Achieving high selectivity and efficiency in photoelectrochemical CO2 reduction remains a key challenge in solar-to-fuel conversion. Here, we report a CuZn alloy-modified black silicon (b-Si) photocathode fabricated via photo-assisted electrodeposition, achieving exceptional performance for selective CH4 generation. The hierarchical porous b-Si substrate enhances photon absorption and charge separation, while the Cu-Zn bimetallic catalyst tunes the surface electronic structure to favor methane production. The optimized Cu88Zn12@b-Si photocathode delivers a maximum CH4 Faradaic efficiency (FE) of 40%, outperforming both monometallic Cu and Zn catalysts. Compared to Cu@b-Si, the Cu88Zn12 case exhibits a 2.28-fold increase in CH4 efficiency at –0.99 V vs. RHE and a 0.2 V lower onset potential for CH4 formation. In situ X-ray absorption spectroscopy and in situ Raman analyses reveal stronger *CO binding and earlier *CHO intermediate formation, facilitated by hot electron excitation from localized surface plasmon resonance (LSPR) and enhanced electron transfer from Zn. The alloy interface effectively stabilizes Cu0, increases *CO coverage, and suppresses hydrogen evolution, enabling efficient and selective CO2 reduction. These results establish CuZn@b-Si as a high-performance, scalable platform for solar-driven methane production and offer mechanistic insights into plasmon-activated photoelectrochemical system.
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