Synergistic Bimetallic Sites in 2D-on-2D Heterostructures for Enhanced C–N Coupling in Sustainable Urea Synthesis
G. Bharath, Karthigeyan Annamalai, Anuj Kumar, Selvakumar Palanisamy, Mohammad Abu Haija, Fawzi Banat
Abstract
High Resolution Image Download MS PowerPoint Slide Electrochemical conversion of CO 2 and N 2 to produce “green urea” using renewable energy represents a promising avenue for CO 2 mitigation. A bifunctional electrocatalyst with a desirable composition and structure is highly required for the electrochemical reduction of CO 2 and N 2 (CO 2 N 2 RR) into urea. Herein, Ru–Pd alloyed nanoparticles were successfully incorporated into 2D WO 3 and MXene nanosheets, resulting in the formation of Ru–Pd/WO 3 /MXene heterostructures. The catalyst significantly enhances electrocatalytic C–N coupling in CO 2 and N 2 reduction, resulting in increased urea yield. The electrochemical reduction initially converts CO 2 into *CO, which then undergoes direct coupling with N 2 to form urea through continuous protonation. Simultaneously, water molecules are oxidized on the bifunctional Ru–Pd/WO 3 /MXene electrodes. The mechanism of C–N coupling for urea formation is elucidated through density functional theory (DFT) calculations. The Ru–Pd/WO 3 /MXene catalyst exhibits a noteworthy urea yield of 227 μg urea mg cat –1 h –1 with a faradaic efficiency of 23.7%. The detailed understanding of the CO 2 N 2 RR mechanism and the recyclable properties of the electrode emphasizes its suitability for prolonged use. This study not only presents a road map for advancing electrolysis but also provides profound insights into the fundamental chemistry of C–N coupling reactions.