Effect of F Doping on CO2 Electrocatalytic Performance of Zinc-Based Rare Earth Layered Double Hydroxides.

As one of the major greenhouse gases, CO2 is significantly influencing global climate change. Efficient utilization of CO2 is considered an important approach to address the current environmental and energy challenges. In particular, using CO2 as a raw material for the production of hydrocarbons is an attractive strategy for reducing carbon emissions while ensuring a stable energy supply. In this study, fluorine (F) doped ZnLa layered double hydroxide (F-ZL-LDH) and F-doped ZnCe layered double hydroxide (F-ZC-LDH) were prepared using a hydrothermal synthesis method. The materials' structural composition and morphology were analyzed using X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The research results demonstrate that both catalysts exhibit abundant active sites, high selectivity, and excellent electrocatalytic performance for CO2RR to generate CO, with Faradaic efficiencies reaching 89.29% and 89.87% for F-ZL-LDH and F-ZC-LDH, respectively. The doping of fluorine results in the presence of numerous defects and pore structures on the surfaces of F-ZC-LDH and F-ZL-LDH, increasing the surface active area and enhancing charge transfer rates. Meanwhile, F doping facilitates CO2 adsorption and mass transfer on the electrode surface. Moreover, F doping in the catalysts also restricts the adsorption and desorption of *H during the competing hydrogen evolution reaction (HER) process. The effective management and rapid conversion of CO2 to various organic compounds and chemical fuels to facilitate carbon cycle and reduce atmospheric CO2 concentration have become a hot topic in current technological advances worldwide. Among the various electrocatalytic CO2 reduction reaction (CO2RR) products, carbon monoxide (CO) is the product with the highest kinetic accessibility. In this paper, F-ZL-LDH and F-ZC-LDH composite materials were prepared using a hydrothermal synthesis method. Based on preliminary studies, a molar ratio of M2+:M3+ of 3:1 was determined to provide better catalytic performance,and ammonium fluoride content of 30% of the cation molar ratio of M2+ + M3+. The introduction of fluorine (F) improves the catalytic performance of both materials, with a greater enhancement observed for ZL-LDH. At − 1.3V vs. RHE potential, The research results demonstrate that both catalysts exhibit abundant active sites, high selectivity, and excellent electrocatalytic performance for CO2RR to generate CO, with Faradaic efficiencies reaching 89.29% and 89.87% for F-ZL-LDH and F-ZC-LDH, respectively. the fluorination treatment of ZC-LDH and ZL-LDH catalysts significantly enhances their electrocatalytic activity for the CO2 reduction reaction, particularly for the production of CO. These findings contribute to the development of efficient catalysts for CO2 electrochemical reduction and hold promise for advancing the field of CO2 utilization and renewable energy conversion. [ABSTRACT FROM AUTHOR]