Bi2S3 in situ bridges BiVO4 and MoS2 for photoelectrochemical ammonia production

Photoelectrochemical (PEC) technology offers a promising strategy for the simultaneous synthesis of green ammonia (NH 3 ) and the utilization of nitrate (NO 3 − ) pollutants in wastewater. However, the low carrier separation efficiency of a bare matrix significantly limits the NH 3 production efficiency and selectivity. In this study, BiVO 4 /O-Bi 2 S 3 /MoS 2 (BVO/O-BS/MS) cascade heterostructure has been successfully designed via one-pot in situ sulfurization. Bi 2 S 3 as an intermediate transition phase effectively connects BiVO 4 and MoS 2 , forming a tightly integrated heterostructure. Due to the cascaded pathways between the three phases, BVO/O-BS/MS exhibits ideal light absorption, charge separation efficiency, and reaction kinetics characteristics. Electrochemical measurements reveal that BVO/O-BS/MS possesses the lowest charge transfer resistance and the largest electrochemical active surface area. Consequently, it achieves a superior NH 3 yield of 17.4 μg h −1 cm −2 at −0.1 V vs. RHE, which is 2.4 times higher than that of pristine BiVO 4 , along with high selectivity and excellent stability over multiple cycles. This work validates the effectiveness of cascaded heterostructures in enhancing the performance of PEC nitrate reduction reaction and further provides valuable insights for sustainable NH 3 production and wastewater treatment.