Is transition metal phthalocyanines active for urea synthesis via electrocatalytic coupling of CO2 and N2?

Abstract

Electrocatalytic coupling of CO2 and N2 to synthesize urea presents a promising approach to address global energy and environmental challenges. Despite the potential, developing an efficient catalyst capable of activating both CO2 and N2 while suppressing side reactions remains a significant challenge. Recent studies have indicated that CuPc and CoPc exhibit notable activity in this process. Herein, we report a theoretical analysis of the catalytic performance of 3d-5d transition metal phthalocyanines (MPcs) in the electrocatalytic urea synthesis reaction. Our findings reveal that MPcs generally exhibit limited activity due to the poor competitiveness of N2for adsorption sites and the high energy barrier associated with CO-N2 coupling, which hinders their ability to compete with CO reduction and/or N2 reduction pathways. Furthermore, the coupling between CO and NH2* is either insufficient for N2 reduction or is outcompeted by ammonia formation. We propose that enhancing N2 adsorption could facilitate C-N coupling, offering a potential strategy for the design of single-atom catalysts aimed at improving urea synthesis efficiency.