Porous BiVO₄/Boron-Doped Diamond Heterojunction Photoanode with Enhanced Photoelectrochemical Activity

Constructing heterojunction is an attractive strategy for promoting photoelectrochemical (PEC) performance in water splitting and organic pollutant degradation. Herein, a novel porous BiVO₄/Boron-doped Diamond (BiVO₄/BDD) heterojunction photoanode containing masses of ultra-micro electrodes was successfully fabricated with an n-type BiVO₄ film coated on a p-type BDD substrate by magnetron sputtering (MS). The surface structures of BiVO₄ could be adjusted by changing the duration of deposition (T_d). The morphologies, phase structures, electronic structures, and chemical compositions of the photoanodes were systematically characterized and analyzed. The best PEC activity with the highest current density of 1.8 mA/cm² at 1.23 V_RHE was achieved when T_d was 30 min, and the sample showed the highest degradation efficiency towards tetracycline hydrochloride degradation (TCH) as well. The enhanced PEC performance was ascribed to the excellent charge transport efficiency as well as a lower carrier recombination rate, which benefited from the formation of BiVO₄/BDD ultra-micro p-n heterojunction photoelectrodes and the porous structures of BiVO₄. These novel photoanodes were expected to be employed in the practical PEC applications of energy regeneration and environmental management in the future.