In-situ sulfidation induced Bi2S3 heterogeneous phase on CuBi2O4 for boosting photoelectrochemical ammonia production

Photoelectrochemical nitrate reduction reaction (PEC-NIRR) provides a sustainable solution for addressing nitrogen-containing wastewater pollution and green ammonia synthesis. However, the reported catalysts are still limited by issues such as low carrier separation efficiency and competition from the hydrogen evolution reaction (HER). A surface sulfidation strategy was employed to epitaxially grow Bi2S3 in situ on the surface of CuBi2O4, successfully constructing a CuBi2O₄/Bi2S3 catalyst. Based on the narrow bandgap (1.67eV) and sulfur atom active sites of Bi2S3, a type II band arrangement and atomic level contact has been configured. The oxygen vacancy (Ov) concentration could be regulated to 48.98%, significantly promoting charge separation and the generation of hydrogen radicals (H*). Under illumination, the CuBi2O₄/Bi2S3 achieves a high NH₃ production rate of 33.69 μg h⁻¹ cm⁻², which is 3.84 times that of CuBi2O4. The by-product NO₂⁻ production rate significantly depressed, contributing to an excellent selectivity (59.71 %). FTIR and ¹H NMR spectroscopic analyses further confirm that NH₃ generation is entirely derived from NO3-. Therefore, this work offering novel providing a new strategy of in-situ sulfidation for boosting the intrinsic activity of polymetallic oxide catalyst.