Expediting Industrial Electrochemical Nitrate‐to‐Ammonia via a Heterogeneous Trap Architecture‐Driven Microconvection Catalyst With Enhanced NH ₃ /Heat Gradient

Abstract In this work, we report a heterogeneous trap architecture‐driven microconvection catalyst with enhanced NH ₃ /heat gradient enabled by designing built‐in double heterostructure of Ni‐Bi‐S catalytic layer with intrinsic ammonia/heat gradient combining 3D inverted biomimetic mushroom (IBM) lattice structure with trap effect‐driven enhanced ammonia/heat gradient. The crystal Bi ₂ S ₃ /amorphous Ni heterostructure compared with crystal Ni ₃ S ₂ /amorphous Ni heterostructure can effectively low the binding energy between electron and Ni orbit, enhance electron transfer ability, generate more charge accumulation at the junctions within heterostructures, slow *H release of hydrolysis couple process, accelerate *H consumption of nitrate reduction process, reduce NH ₃ ‐formation free energy barrier and produce more molecular ammonia, thereby forming intrinsic ammonia gradient and heat gradient inside Ni‐Bi‐S catalytic layer. Besides, 3D heterogeneous trap structure is conducive to the formation of higher irradiation gradient, heat gradient and NH ₃ gradient on the catalyst surface, thereby forming stronger thermal/NH ₃ convection. Notably, the as‐prepared microconvection electrocatalyst can achieve a high ammonia yield of 4.87 mmol ⁻¹ h ⁻¹ cm ⁻² in the ultra‐low polarization potential ‐0.17V (vs Reversible Hydrogen Electrode (RHE)) at industrial 800 mA/cm ² current density under electric‐light field condition, the highest NH ₃ yield improvement rate can reach 44.5%, and the highest energy saving rate can up to 27.8% compared with pure electric field conditions.