Amorphous CoO-SnO₂ Nanocubes with dual sites enable efficient Electrocatalytic Ammonia synthesis via pathway...

Amorphous metal oxides are attracting considerable attention as electrocatalysts due to their higher density of catalytically active sites and unique electronic structure. Traditional tin-based amorphous oxide materials, however, suffer from low intrinsic electronic conductivity and sluggish ion diffusion kinetics, limitations that hinder their application. Herein, we successfully developed the amorphous CoO-SnO₂ nanocube material using co-precipitation and calcination. It has been demonstrated by means of microstructural and surface analysis that the amorphous framework characterized by uniformly distributed CoSn dual sites induces strong electronic interaction, thereby effectively modulating the adsorption of key reaction intermediates. This catalyst achieves exceptional NRR performance with 93 μg h^-1 mg_cat^-1 NH₃ yield and 59 % Faradaic efficiency (FE) at -0.5 V vs. RHE, outperforming monometallic controls. Mechanistic studies, incorporating in-situ FTIR and DFT calculations, demonstrate that the CoSn electronic structure modulation directs the reaction along an unconventional "alternating-distal" hybrid pathway. In this pathway, the dual-site configuration regulates the adsorption energy of intermediates and reduces the energy barrier of the rate-determining step. This work demonstrates amorphous bimetallic oxide engineering as a paradigm for efficient electrocatalytic ammonia synthesis.