Laser Photochemistry Laboratory

#224. Electrocatalytic Ammonia Production from Nitrite via Dual-Site Co3O4/NiO Catalysts Derived from Laser-Induced Cyanonickelate Frameworks
Talshyn Begildayeva†, Jayaraman Theerthagiri†, Ahreum Min, Cheol Joo Moon, Myong Yong Choi*

Abstract: Herein,  we  report  the  pioneering  synthesis  of  the  cobalt-nickel coordination 

frameworks (Co(H2O)2·Ni(CN)4, CoNi-CF) via pulsed laser irradiation in liquids (PLIL). The 

distinctive morphology of CoNi-CF has attracted considerable attention as a potential template to 

produce Co3O4/NiO composites with varying Co and Ni ratios. After subjecting CoNi-CF to a 

high-temperature calcination process at 400°C, the resulting Co3O4/NiO composites displayed 

dual-active canters for efficient electrochemical nitrite (NO2−) reduction to ammonia (NH3). 

Optimizing  the Co:Ni  ratio  at 1:0.75 yielded Co3O4/NiO with exceptional  performance, 

achieving a remarkable 99.4% Faradaic efficiency in NH3 production while maintaining a 96.1% 

mass balance at −1.2 V vs. Ag/AgCl. Furthermore, this composite displayed long-term stability, 

degrading 60.82% of NO2− in 180 min, with high NH3 yield rates (2012.03 μM h−1 cm−2) at −1.6 

V vs. Ag/AgCl. The superior performance in NO2− reduction to NH3 can be attributed to the 

unique structural  features inherited from  CoNi-CF, including well-defined and self-standing 

Co3O4 and  NiO  phases.  Synergistic  effects  at  the  oxide  interface  enhance  electrochemical 

performance and facilitate efficient charge transfer kinetics of Co3O4/NiO, underscoring the 

unique potential of these composite materials.