Highly stabilized and selective ammonia electro-oxidation over CuNi metallic glass nanoarray

Abstract

Electrochemical nitrogen looping represents a promising carbon-free and sustainable solution for the energy transition, in which electrochemical ammonia oxidation stays at the central position. However, the various nitrogen-containing intermediates tend to poison and corrode the electrocatalysts, even the state-of-the-art noble-metal ones, which is worsened at a high applied potential. Herein, we present an ultrarapid laser quenching strategy for constructing a corrosion-resistant and nanostructured CuNi alloy metallic glass electrocatalyst. In this material, single-atom Cu species are firmly bonded with the surrounding Ni atoms, endowing exceptional resistance against ammonia corrosion relative of conventional CuNi alloys. Remarkably, a record-high durability for over 300 h is achieved. Ultrarapid quenching also allows a much higher Cu content than typical single-atom alloys, simultaneously yielding a high rate and selectivity for ammonia oxidation reaction (AOR). Consequently, an outstanding ammonia conversion rate of up to 95% is achieved with 91.8% selectivity toward nitrite after 8 h. Theoretical simulations reveal that the structural amorphization of CuNi alloy could effectively modify the electronic configuration and reaction pathway, generating stable single-atom Cu active sites with low kinetic barriers for AOR. This ultrarapid laser quenching strategy thus provides a new avenue for constructing metallic glasses with well-defined nanostructures, presenting feasible opportunities for performance enhancement for AOR and other electrocatalytic processes.

Keywords

ammonia oxidation reaction / CuNi / laser quenching / metallic glasses