Single-crystal Integrated Photoanodes Based on 4H-SiC Nanohole Arrays for Boosting Photoelectrochemical Water Splitting Activity.

Photoelectrochemical (PEC) splitting of water into H2 and O2 by direct use of sunlight is an ideal strategy for the production of clean and renewable energy, which fundamentally relies on the exploration of advanced photoanodes with high performance. In the present work, we reported the single-crystal integrated photoanode, that is the 4H-SiC nanohole arrays (active materials) and SiC wafer substrate (current collector) are established into a totally single-crystal configuration without interfaces, which were based on a two-step electrochemical etching process. The as-fabricated SiC photoanode showed a rather low onset potential of -0.016 V vs. RHE, as well as a high photocurrent density of 3.20 mA/cm2 vs. RHE 1.23 V, which were both superior to those of SiC ones ever reported. Furthermore, such rationally designed photoanode behaved a fast photoresponse, wide photoresponse wavelength range and long-term stability, representing their overall excellent PEC performances.