Single-crystal N-doped SiC nanochannel array photoanode for efficient photoelectrochemical water splitting

Abstract

We report, for the first time, the exploration of an efficient photoanode based on an N-doped 4H-SiC nanochannel array for photoelectrochemical (PEC) water splitting, which is fabricated through an anodic oxidation approach. The SiC photoanode yields a high photocurrent density of 2.41 mA cm⁻² at 1.4 V vs. Ag/AgCl under 1.5G simulated sunlight. Meanwhile, the as-constructed photoanode presents a fast photoresponse and wide photoresponse wavelength range. The high orientation of SiC nanochannel arrays, the single-crystal nature of the whole SiC film and the incorporated N dopants are responsible for the enhanced PEC performance, with the benefits of substantially improving the light capability and extending the optical absorption edges, as well as promoting transport and separation of photoexcited charge carriers.