Sulfur dots–graphene nanohybrid: a metal-free electrocatalyst for efficient N2-to-NH3 fixation under ambient conditions
NH3 is an important chemical with a wide range of applications, but its synthesis mainly relies upon the harsh Haber–Bosch process with huge CO2 emission. Electrochemical N2 reduction offers a carbon-neutral process to convert N2 to NH3 under ambient conditions, but it requires efficient and stable catalysts to drive the N2 reduction reaction. Herein, we report that a sulfur dots–graphene nanohybrid acts as a metal-free electrocatalyst for ambient N2-to-NH3 conversion with excellent selectivity. When operated in 0.5 M LiClO4, this electrocatalyst achieves a large NH3 yield of 28.56 μg h−1 mgcat.−1 and a high Faradaic efficiency of 7.07% at −0.85 V vs. reversible hydrogen electrode. Notably, it also shows good electrochemical stability.