Manipulating Electron Structure through Dual-Interface Engineering of 3C-SiC Photoanode for Enhanced Solar Water Splitting.

Interface engineering is crucial for enhancing the efficiency of semiconductor-based solar energy devices. In this work, we report a novel dual-interface engineering strategy by designing a Ni(OH)/CoO/3C-SiC photoanode that achieves remarkable enhancements in photoelectrochemical (PEC) water splitting performance. The optimized photoanode delivers a photocurrent density of 1.68 mA cm at 1.23 V vs the reversible hydrogen electrode (RHE), representing an 8-fold increase compared to pristine 3C-SiC, along with excellent operational stability. In this architecture, CoO serves as a highly efficient hole-extraction layer and forms a p-n junction with 3C-SiC, enhancing the separation of photogenerated electron-hole pairs. At the Ni(OH)/CoO interface, the formation of Ni-O-Co bonds facilitates rapid charge transfer and accelerates oxygen evolution reaction (OER) kinetics. The microwave photoconductivity decay (μ-PCD) measurements confirm a prolonged minority carrier lifetime, demonstrating the critical role of electronic structure modulation in improving charge separation and reducing recombination. Using advanced synchrotron radiation and X-ray absorption spectroscopy, we unveil critical modifications to the interfacial electronic structure induced by the dual-interface engineering and their roles in enhancing PEC performance. These findings establish a clear relationship between electronic structure modulation, charge carrier dynamics, and PEC performance, providing new insights into interface design strategies for highly efficient solar-driven water splitting systems.