Efficient urea electrosynthesis from carbon dioxide and nitrate via alternating Cu–W bimetallic C–N coupling sites

Abstract

Electrocatalytic urea synthesis is an emerging alternative technology to the traditional energy-intensive industrial urea synthesis protocol. Novel strategies are urgently needed to promote the electrocatalytic C–N coupling process and inhibit the side reactions. Here, we report a CuWO4 catalyst with native bimetallic sites that achieves a high urea production rate (98.5 ± 3.2 μg h−1 mg−1cat) for the co-reduction of CO2 and NO3− with a high Faradaic efficiency (70.1 ± 2.4%) at −0.2 V versus the reversible hydrogen electrode. Mechanistic studies demonstrated that the combination of stable intermediates of *NO2 and *CO increases the probability of C–N coupling and reduces the potential barrier, resulting in high Faradaic efficiency and low overpotential. This study provides a new perspective on achieving efficient urea electrosynthesis by stabilizing the key reaction intermediates, which may guide the design of other electrochemical systems for high-value C–N bond-containing chemicals.

Electrocatalysis of nitrogen pollution: transforming nitrogen waste into high-value chemicals

“…For instance, the faradaic efficiency of NO x − reduction into ammonia or CO 2 –NO x − co-reduction into C–N products can be enhanced by introducing CO 2 from flue gas. 41,42,56,57,72–78…”

Photoelectrochemical Urea Synthesis from Nitrate and Carbon Dioxide on GaN Nanowires

“…Furthermore, rational design of the Cu−W bimetallic C−N coupling sites improved the performance of electrocatalysts, resulting in high FE urea > 70%. 36 However, the applied potential in electrochemical urea synthesis is still needed, and the product selectivity is still much lower than that of the individual CO 2 -to-CO and NO 3 − -to-NH 3 conversion reactions, which typically show faradaic efficiency above 80%.…”

“…In particular, experiments with In­(OH) 3 and InOOH have achieved high selectivity of urea generation (FE urea > 50%) at cathodic potentials of −0.6 and −0.5 V versus the reversible hydrogen electrode ( V RHE ), respectively. , Theoretical calculations have suggested that the facilitated C–N coupling between *NO 2 – and *CO 2 intermediates on In­(OH) 3 at an early stage of the reaction can promote urea synthesis more effectively than the conventional C–N coupling between *NH 2 and *CO. Furthermore, rational design of the Cu–W bimetallic C–N coupling sites improved the performance of electrocatalysts, resulting in high FE urea > 70% . However, the applied potential in electrochemical urea synthesis is still needed, and the product selectivity is still much lower than that of the individual CO 2 -to-CO and NO 3 – -to-NH 3 conversion reactions, which typically show faradaic efficiency above 80%.…”

Enhancing Electrocatalytic Synthesis of Glycine with CuPb1ML Electrode Synthesized via Pb UPD

“…[15,16] Therefore, it is not surprising that CÀ N bond forming electroreductive reactions frequently use Cu-based materials. [17][18][19] The problem with using Cu based catalysts is that Cu can also perform HER, especially when using an acidic electrolyte. [20] In this work, we therefore set out to find a method which allows us to limit the HER of a Cu electrode and thereby improve its efficiency in electroreductive CÀ N bond formation in aqueous acid media.…”