Microenvironment Engineering to Promote Selective Ammonia Electrosynthesis from Nitrate over a PdCu Hollow Catalyst.

Abstract

The electrosynthesis of recyclable ammonia (NH3 ) from nitrate under ambient conditions is of great importance but still full of challenges for practical application. Herein, an efficient catalyst design strategy is developed that can engineer the surface microenvironment of a PdCu hollow (PdCu-H) catalyst to confine the intermediates and thus promote selective NH3 electrosynthesis from nitrate. The hollow nanoparticles are synthesized by in situ reduction and nucleation of PdCu nanocrystals along a self-assembled micelle of a well-designed surfactant. The PdCu-H catalyst shows a structure-dependent selectivity toward the NH3 product during the nitrate reduction reaction (NO3 - RR) electrocatalysis, enabling a high NH3 Faradaic efficiency of 87.3% and a remarkable NH3 yield rate of 0.551mmol h-1 mg-1 at -0.30V (vs reversible hydrogen electrode). Moreover, this PdCu-H catalyst delivers high electrochemical performance in the rechargeable zinc-NO3 - battery. These results provide a promising design strategy to tune catalytic selectivity for efficient electrosynthesis of renewable NH3 and feedstocks.