Te-Doped Pd Nanocrystal for Electrochemical Urea Production by Efficiently Coupling Carbon Dioxide Reduction with Nitrite Reduction.

The renewable electricity-driven reduction of carbon dioxide (CO2RR) is a promising technology for carbon utilization. However, it is still a challenge to broaden the application of CO2RR. Herein, we report a Te-doped Pd nanocrystals (Te-Pd NCs) for promoting urea synthesis by coupling CO2RR with electrochemical reduction of nitrite. The electrochemical synthesis of urea has been achieved with nearly 12.2% Faraday efficiency (FE) and 88.7% N atom efficiency (NE) at -1.1 V versus reversible hydrogen electrode (vs RHE), much higher than those of pure Pd NCs (4.2% FE and 21.8% NE). Significantly, an FE of ∼10.2% and an NE of ∼82.3% for urea solution production via an optimized flow cell system have been realized, where a solution with up to 0.95 wt % of urea has been obtained. Mechanistic insights show that Te-doping not only optimizes the CO2/CO adsorption but also promotes NH3 production, fully meeting the requirements of urea synthesis.