Modulating photoelectrochemical water splitting performance by constructing a type-II heterojunction between g-C3N4 and BiOI

In this work, a type-II heterojunction was constructed between g-C3N4 and BiOI by ultrasonically assisted hydrothermal synthesis for photoelectrochemical water splitting. The g-C3N4 was decorated on BiOI microspheres with a well-defined heterostructure, which reduced the charge recombination process, consistent with the data from photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The g-C3N4/BiOI hybrid material exhibits enhanced photocurrent density, similar to 13-fold higher than that of g-C3N4 and similar to 2 fold higher than pristine BiOI. Furthermore, high stability was achieved for the g-C3N4/BiOI hybrid material with 6 wt% g-C3N4 for up to 6000 s at 1.23 V vs. RHE, and the photo-conversion efficiency reached 14-fold higher than that of g-C3N4 and 1.6 times higher than that of BiOI microspheres. The high photoelectrocatalytic performance achieved by the 6% g-C3N4/BiOI material was attributed to the formation of type-II heterojunction between the g-C3N4 and BiOI interfaces that could facilitate the photoinduced charge separation-migration and thereby minimize the charge recombination process.

Automated summary

In this study, a type-II heterojunction was constructed between g-C3N4 and BiOI by ultrasonically assisted hydrothermal synthesis for efficient photoelectrochemical water splitting. The resulting hybrid material exhibited enhanced photocurrent density and stability, attributed to the formation of the heterojunction that facilitated photoinduced charge separation-migration and minimized charge recombination. The performance of the 6% g-C3N4/BiOI material surpassed that of g-C3N4 and BiOI microspheres, demonstrating its significant potential for photoelectrocatalytic applications.