Abstract

Electrochemical energy generation and NH 3 production via nitrite (NO 2− ) conversion through NO 2− reduction reaction (NO 2RR) is a viable approach. Prussian Blue analogs (PBAs)–based electrocatalysts are potential candidates for NO 2RR owing to their good activity and selectivity.

Herein, to the best of our knowledge, for the first time, we report a facile synthesis of a flowerlike copper–cobalt PBA sulfide (CuCoPBA-S) using pulsed laser irradiation in liquid and investigate its formation mechanism using acoustic levitation coupled with in situ micro-Raman spectroscopy. This approach enables contaminant-free, rapid, and cost-effective synthesis of electrocatalysts. The sulfidation process is shown to be time dependent in the formation of ordered/disordered flower-like CuCoPBA-S structures. The CuCoPBA-S considerably influences the NO 2RR, achieving a Faradaic efficiency of 80.91% and an NH 3 yield rate of 3394.1 µg h −1

cm −2 at a fixed potential of −0.5 V vs. the reversible hydrogen electrode. Moreover, density functional theory analysis validates the NO 2RR pathway facilitated by CuCoPBA-S during the electrocatalytic conversion of NO 2− to NH 3, and the rate-determining step in the pathway is the hydrogenation of *NH 2O to *NH 2OH.