Heterostructured Bi₂S₃/MoS₂ Nanoarrays for Efficient Electrocatalytic Nitrate Reduction to Ammonia Under Ambient Conditions

Developing efficient electrocatalysts to realize the nitrate reduction reaction (eNO3–RR) for ammonia synthesis as an alternative to the traditional Haber–Bosch production process is of great significance. Herein, the heterostructured Bi2S3/MoS2 nanoarrays were successfully synthesized by Bi2S3 nanowires anchored on MoS2 nanosheets. Owing to the interfacial coupling effect, both particular surface area and exposure active sites increase. Density functional theory further uncovered that the excellent activity originates from charge transfer of the interface and a low potential barrier of 0.58 eV for hydrogenation of *NO to *NOH on Bi2S3/MoS2. Compared with pure Bi2S3 and MoS2 catalysts, the heterostructured Bi2S3/MoS2 nanoarrays exhibit a superior NH3 yield of 15.04 × 10–2 mmol·h–1·cm–2 and a Faraday efficiency of 88.4% at −0.8 V versus the reversible hydrogen electrode. This work provides a new avenue to explore advanced electrocatalysts, which is expected to shorten the distance from the practical application of the eNO3–RR technology.