College of Biological, Chemical Science and Engineering Jiaxing University, Jiaxing, Zhejiang 314001, PR China.
College of Biological, Chemical Science and Engineering Jiaxing University, Jiaxing, Zhejiang 314001, PR China; Institute of Industrial Catalysis, College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, PR China.
J Colloid Interface Sci. 2023 Jul;641:990-999. doi: 10.1016/j.jcis.2023.03.135. Epub 2023 Mar 24.
Urea is ubiquitous in agriculture and industry, but its production consumes a lot of energy. The conversion of nitrogen (N) and carbon dioxide (CO) into urea via an electrocatalytic CN coupling reaction under ambient conditions would be a major boon to sustainable development. However, designing a metal - free catalyst with high activity and selectivity for urea remains a major challenge. Herein, by means of density functional theory (DFT) and ab - initio molecular dynamics (AIMD) computations, the B cluster doped on nitrogenated graphene (CN) substrate catalyst (B@CN) with superior stability was designed for electrocatalytic urea synthesis starting from the CO and N through four reaction mechanisms. The nature of the co-adsorption activation of CO and N on the B@CN catalyst was investigated, the electrochemical proton - electron transfer steps and the CN thermochemical coupling led to the synthesis of urea. The study showed that the B@CN catalyst exhibited high catalytic activity for urea synthesis with the lowest limiting potential of - 1.01 V following the *HNNH mechanism compared with other mechanisms. The potential - determining step (PDS) is the formation of the *CO+*NHNH species. However, the two - step CN coupling barriers of *NCON species are 0.13 eV and 0.60 eV using AIMD and a "slow - growth" sampling approach in an explicit water molecules model. Calculations also showed that the byproducts of carbon monoxide (CO), methane (CH), methanol (CHOH), ammonia (NH), and hydrogen (H) can be inhibited on the B@CN catalyst. Therefore, the metal - free catalyst not only has a good performance for the hydrogenation of CO and N promoting the electrochemical reaction, but also facilitates CN thermochemical coupling for urea synthesis. This work provides new insights into the synthesis of urea via the CN coupling reaction on a metal - free electrocatalyst, a process that could contribute to greenhouse gas mitigation to help meet carbon neutrality targets.
尿素在农业和工业中无处不在，但它的生产消耗了大量的能源。在环境条件下，通过电催化 CN 偶联反应将氮（N）和二氧化碳（CO）转化为尿素，这将是可持续发展的一大福音。然而，设计一种具有高活性和选择性的金属免费催化剂来合成尿素仍然是一个主要挑战。在此，通过密度泛函理论（DFT）和 ab - 初始分子动力学（AIMD）计算，设计了具有优异稳定性的氮掺杂石墨烯（CN）基底上的 B 团簇掺杂催化剂（B@CN），用于通过四种反应机制从 CO 和 N 开始电催化合成尿素。研究了 CO 和 N 在 B@CN 催化剂上共吸附活化的性质，电化学质子 - 电子转移步骤和 CN 热化学偶联导致了尿素的合成。研究表明，与其他机制相比，B@CN 催化剂在HNNH 机制下，尿素合成的最低极限电位为-1.01V，表现出较高的催化活性。决定电位的步骤（PDS）是CO+*NHNH 物种的形成。然而，使用 AIMD 和显式水分子模型中的“缓慢生长”采样方法，*NCON 物种的两步 CN 偶联势垒分别为 0.13eV 和 0.60eV。计算还表明，一氧化碳（CO）、甲烷（CH）、甲醇（CHOH）、氨（NH）和氢（H）的副产物可以在 B@CN 催化剂上被抑制。因此，该无金属催化剂不仅对 CO 和 N 的加氢具有良好的性能，促进了电化学反应，而且有利于 CN 热化学偶联合成尿素。这项工作为无金属电催化剂上通过 CN 偶联反应合成尿素提供了新的见解，这一过程有助于减少温室气体，有助于实现碳中和目标。
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