Efficient N2 Electrofixation to NH3 Through Optimizing Binder‐Catalyst Configuration

Abstract

AbstractNitrogen electrofixation under ambient conditions is a promising approach to synthesize ammonia sustainably but improving the yield and efficiency remains a challenge. This is due to the competition between the nitrogen electrofixation and hydrogen evolution reactions, which can be depressed through appropriate working electrode design. This study investigated the influence of the catalyst‐binder configuration on ammonia yield and Faradic efficiency. A series of working electrodes were tested in an aqueous system, with the proton and electron transfer on the working electrode found to be dependent on the catalyst material, binder material, and binder hydrophobicity. The use of a binder with low proton/electron conductivity increased Faradic efficiency by hindering the hydrogen evolution reaction and reducing charge transfer to the catalytic material. Utilising a hydrophobic binder significantly improved ammonia yield. Furthermore, nitrogen sorption experiments revealed that the catalyst‘s nitrogen affinity exerts a greater influence on ammonia yield than the binder‘s affinity. The best performance was observed for a semi‐conductive catalyst based on vanadium, integrated within a highly hydrophobic perfluorinated binder. At ambient conditions in 0.1 M hydrogen chloride, 39.3±4.3  of ammonia was synthesized with 38.5±4.5 % Faradic efficiency at −0.2 V versus a reversible hydrogen electrode.