Laser-Sculpted High-Entropy Alloy Enables Ammonia-Electricity Co-Production via Nitrite Remediation in Zn-Nitrite Batteries

Abstract

Herein, this study reports the synthesis of a uniform, sphere-like NiCoFeRuIr high-entropy alloy (HEA) via the pulsed laser irradiation in liquid method. This method enables the rapid, reducing-agent-free, and energy-efficient fabrication of HEAs under ambient conditions, thereby overcoming the limitations associated with conventional high-temperature alloying or chemical reduction methods. The resulting NiCoFeRuIr HEA exhibits outstanding nitrite reduction reaction (NO2 -RR) performance, achieving a high NH3 yield rate of 2.34 mg<middle dot>h-1<middle dot>cm-2 and Faradaic efficiency of 95.78% at -0.6 V versus the reversible hydrogen electrode. An enhanced electrocatalytic activity is attributed to unique synergistic interactions among multiple metal components in NiCoFeRuIr HEA, optimizing the adsorption energy of intermediates and accelerating reaction kinetics. Mechanistic insights obtained from in situ Raman spectroscopy, ex situ X-ray diffraction, and density functional theory calculations further support the origin of the outstanding NO2 -RR performance of the NiCoFeRuIr HEA electrocatalyst. Furthermore, NiCoFeRuIr HEA serves as an efficient cathode in a Zn-nitrite battery, enabling simultaneous NO2 - remediation, ammonia (NH3) production, and electricity generation with a power density of 3.80 mW<middle dot>cm-2. Thus, this study highlights the potential of the pulsed laser-driven synthesis of HEA electrocatalysts, paving the way for integrated pollutant remediation, green chemical production, and sustainable energy applications.