Demonstration of irradiation-resistant 4H-SiC based photoelectrochemical water splitting

4H silicon carbide (4H-SiC) has gained a great success in high-power electronics, owing to its advantages of wide bandgap, high breakdown electric field strength, high carrier mobility, and high thermal conductivity. Considering the high carrier mobility and high stability of 4H-SiC, 4H-SiC has great potential in the field of photoelectrochemical (PEC) water splitting. In this work, we demonstrate the irradiation-resistant PEC water splitting based on nanoporous 4H-SiC arrays. A new two-step anodizing approach is adopted to prepare 4H-SiC nanoporous arrays with different porosity, that is, a constant low-voltage etching followed by a pulsed high-voltage etching. The constant-voltage etching and pulsed-voltage etching are adopted to control the diameter of the nanopores and the depth of the nanoporous arrays, respectively. It is found that the nanoporous arrays with medium porosity has the highest PEC current, because of the enhanced light absorption and the optimized transportation of charge carriers along the walls of the nanoporous arrays. The performance of the PEC water splitting of the nanoporous arrays is stable after the electron irradiation with the dose of 800 and 1600 kGy, which indicates that 4H-SiC nanoporous arrays has great potential in the PEC water splitting under harsh environments.