Bi nanodendrites for highly efficient electrocatalytic NO reduction to NH3 at ambient conditions

Abstract

Electrocatalytic NO reduction into value-added NH3 addresses the need for NO emission abatement and presents a sustainable alternative to the industrial Haber–Bosch process. It is however challenged by unsatisfactory conversion efficiencies due to competitive hydrogen evolution and requires highly active and selective catalysts for NO reduction reaction (NORR). In this work, we report the Bi nanodendrites (Bi NDs) with sufficient exposure of catalytic sites act as a high-efficiency NORR electrocatalyst toward selective NH3 synthesis. This catalyst attains a remarkable NH3 yield of 1194 μg h−1 mg−1cat. and a Faradaic efficiency as high as 89.2% in neutral media, making it one of the most promising aqueous-based NORR catalysts for NO-to-NH3 conversion. Additionally, we coupled Bi NDs-loaded carbon paper into an aqueous Zn–NO battery with a Zn plate anode to provide a peak power density of 2.33 mW cm−2 and an NH3 yield of up to 84.4 μg h−1 cm−2. NO reduction mechanism on the Bi (012) surface is further revealed and discussed with theoretical calculations.