Constructing AgI/BiSI p-n heterojunctions with an internal electric field for efficient degradation of refractory organic pollutants

Designing photocatalysts with p-n heterojunction structures is an effective way to boost the separation of photogenerated carriers and stimulate the photocatalytic degradation activity. Herein, an efficient visible-light responsive AgI/BiSI p-n heterojunction photocatalyst was successfully constructed. X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and electrochemical measurements confirmed that the AgI/BiSI p-n heterojunction structure was beneficial to the separation and transfer of photogenerated carriers, promoting the generation of main active species (•O2− and h+). Furthermore, the photocatalytic degradation rate constants of Acid Red 1 (0.4699 min−1) and metronidazole (0.0730 min−1) over the optimal AgI/BiSI were about 8.4 and 3.0 times higher than those over pure AgI, respectively. This work provides a heterojunction engineering strategy to design high-efficient photocatalysts for the degradation of refractory organic pollutants.