Yang Fangqi, Liang Caihong, Yu Haoming, Zeng Zheling, Lam Yeng Ming, Deng Shuguang, Wang Jun
School of Resource and Environment, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, P. R. China.
Chemistry and Chemical Engineering School, Nanchang University, No. 999 Xuefu Avenue, Jiangxi, 330031, P. R. China.
Adv Sci (Weinh). 2022 Sep;9(25):e2202006. doi: 10.1002/advs.202202006. Epub 2022 Jul 12.
Electrochemical reduction of carbon dioxide (CO ) to ethanol is a promising strategy for global warming mitigation and resource utilization. However, due to the intricacy of C─C coupling and multiple proton-electron transfers, CO -to-ethanol conversion remains a great challenge with low activity and selectivity. Herein, it is reported a P-doped graphene aerogel as a self-supporting electrocatalyst for CO reduction to ethanol. High ethanol Faradaic efficiency (FE) of 48.7% and long stability of 70 h are achieved at -0.8 V . Meanwhile, an outstanding ethanol yield of 14.62 µmol h cm can be obtained, outperforming most reported electrocatalysts. In situ Raman spectra indicate the important role of adsorbed *CO intermediates in CO -to-ethanol conversion. Furthermore, the possible active sites and optimal pathway for ethanol formation are revealed by density functional theory calculations. The graphene zigzag edges with P doping enhance the adsorption of *CO intermediate and increase the coverage of *CO on the catalyst surface, which facilitates the *CO dimerization and boosts the EtOH formation. In addition, the hierarchical pore structure of P-doped graphene aerogels exposes abundant active sites and facilitates mass/charge transfer. This work provides inventive insight into designing metal-free catalysts for liquid products from CO electroreduction.
将二氧化碳(CO₂)电化学还原为乙醇是缓解全球变暖及资源利用的一种很有前景的策略。然而,由于C─C偶联和多次质子-电子转移的复杂性,将CO₂转化为乙醇仍然是一个巨大的挑战,存在活性和选择性低的问题。在此,报道了一种P掺杂的石墨烯气凝胶作为用于将CO₂还原为乙醇的自支撑电催化剂。在-0.8 V时实现了48.7%的高乙醇法拉第效率(FE)和70小时的长稳定性。同时,可获得14.62 µmol h⁻¹ cm⁻²的出色乙醇产率,优于大多数已报道的电催化剂。原位拉曼光谱表明吸附的CO中间体在CO₂到乙醇转化中的重要作用。此外,通过密度泛函理论计算揭示了乙醇形成的可能活性位点和最佳途径。具有P掺杂的石墨烯锯齿边缘增强了CO中间体的吸附并增加了CO在催化剂表面的覆盖度,这有利于CO二聚化并促进乙醇的形成。此外,P掺杂的石墨烯气凝胶的分级孔结构暴露了丰富的活性位点并促进了质量/电荷转移。这项工作为设计用于CO₂电还原制备液体产物的无金属催化剂提供了创造性的见解。