Ag nanoparticles-reduced graphene oxide hybrid: an efficient electrocatalyst for artificial N2 fixation to NH3 at ambient conditions

For N2-to-NH3 fixation, electrocatalytic N2 reduction has become one promising alternative to Haber–Bosch process for its superior environmental protection and low-energy consumption. During this electrochemical conversion, adopting a suitable catalytic material is frequently the first consideration that involves in cost and production efficiency. Herein, Ag nanoparticles-reduced graphene oxide hybrid (Ag NPs-rGO) is designed as a novel Ag-based catalyst that exhibits high-efficiency electrocatalytic performance for N2-to-NH3 conversion. Introducing rGO into the catalyst results in a significant improvement of catalytic activity, for the advanced electrical conductivity of rGO and dispersed Ag NPs anchored on this support material. In a 0.1 M Na2SO4 solution, the Ag NPs-rGO delivers Faradaic efficiency of 3.60% and NH3 yield of 18.86 μg h−1 mg−1 cat. at − 0.7 V versus reversible hydrogen electrode (RHE). By contrast, the Ag NPs attains inferior Faradaic efficiency of 2.25% with NH3 yield of 9.43 μg h−1 mg−1 cat. (− 0.7 V vs RHE). The Ag NPs-rGO also maintains good stability and sustainability during the electrocatalytic process.