Dual-Intermetallic Heterostructure on Hierarchical Nanoporous Metal for Highly Efficient Nitrate Reduction Electrocatalysis.

Electrocatalytic reduction of nitrate to ammonia is a promising strategy for green ammonia production. However, the nitrate reduction reaction (NO₃RR) still suffers from the sluggish kinetics of hydrogenation process and subsequent ammonia desorption. Herein, the nanoporous Cu/Cu₆Sn₅ heterostructure is prepared by dealloying and serves as an efficient catalyst for NO₃RR. The Cu/Cu₆Sn₅ heterostructure improves the affinity of alkali-ionized water, promoting intermediate hydrogenation via enhanced active hydrogen supply. Moreover, NH₃ desorption can also be accelerated by the introduction of the Cu₆Sn₅ phase. As a result, the np-Cu/Cu₆Sn₅ catalyst exhibits a high ammonia yield of 1.2 mmol h^-1 cm^-2 with an excellent Faradaic efficiency of 97%. This work provides an intriguing strategy to enhance the catalytic activity by regulating the intermediates adsorption.