Peng Chen, Luo Gan, Zhang Junbo, Chen Menghuan, Wang Zhiqiang, Sham Tsun-Kong, Zhang Lijuan, Li Yafei, Zheng Gengfeng
Laboratory of Advanced Materials, Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Faculty of Chemistry and Materials Science, Fudan University, Shanghai, 200438, China.
Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, 210023, China.
Nat Commun. 2021 Mar 11;12(1):1580. doi: 10.1038/s41467-021-21901-1.
Electrochemical CO reduction can produce valuable products with high energy densities but the process is plagued by poor selectivities and low yields. Propanol represents a challenging product to obtain due to the complicated C forming mechanism that requires both stabilization of C intermediates and subsequent C-C coupling. Herein, density function theory calculations revealed that double sulfur vacancies formed on hexagonal copper sulfide can feature as efficient electrocatalytic centers for stabilizing both CO and OCCO* dimer, and further CO-OCCO coupling to form C species, which cannot be realized on CuS with single or no sulfur vacancies. The double sulfur vacancies were then experimentally synthesized by an electrochemical lithium tuning strategy, during which the density of sulfur vacancies was well-tuned by the charge/discharge cycle number. The double sulfur vacancy-rich CuS catalyst exhibited a Faradaic efficiency toward n-propanol of 15.4 ± 1% at -1.05 V versus reversible hydrogen electrode in H-cells, and a high partial current density of 9.9 mA cm at -0.85 V in flow-cells, comparable to the best reported electrochemical CO reduction toward n-propanol. Our work suggests an attractive approach to create anion vacancy pairs as catalytic centers for multi-carbon-products.
电化学CO还原可以生产具有高能量密度的有价值产品，但该过程存在选择性差和产率低的问题。由于复杂的C形成机制，丙醇是一种具有挑战性的产物，该机制既需要C中间体的稳定化又需要随后的C-C偶联。在此，密度泛函理论计算表明，在六方硫化铜上形成的双硫空位可作为有效的电催化中心，用于稳定CO和OCCO*二聚体，并进一步实现CO-OCCO偶联以形成C物种，而这在具有单硫空位或无硫空位的CuS上无法实现。然后通过电化学锂调控策略实验合成了双硫空位，在此过程中，硫空位的密度通过充放电循环次数得到了很好的调控。富含双硫空位的CuS催化剂在H型电池中相对于可逆氢电极在-1.05 V时对正丙醇的法拉第效率为15.4±1%，在流动电池中在-0.85 V时具有9.9 mA cm的高部分电流密度，与报道的电化学CO还原制备正丙醇的最佳结果相当。我们的工作提出了一种有吸引力的方法，即创建阴离子空位对作为多碳产物的催化中心。
