In this work, we designed a novel CuO/Al2CuO4 catalyst by a phase and interphase engineering approach, which enables the electrochemical conversion of carbon dioxide to ethylene with ultrahigh activity and selectivity.
Metal oxides are a promising material for designing highly active and selective catalysts for the electrochemical reduction of carbon dioxide (CO 2 RR). Here, we designed a Cu/ceria catalyst with high selectivity of methane production at single-atomic Cu active sites. Using this, we report favorable design concepts that push the product selectivity of methane formation by combining detailed structural analysis, density functional theory (DFT), in situ Raman spectroscopy, and electrochemical measurements. We demonstrate that a higher concentration of oxygen vacancies on the catalyst surface, resulting from more available Cu + sites, enables high selectivity for methane formation during CO 2 RR and can be controlled by the calcination temperature. The DFT calculation and in situ Raman studies indicate that pH controls the surface termination; a more alkaline pH generates hydroxylated surface motifs with more active sites for the hydrogen evolution reaction. These findings provide insights into designing an efficient metal oxide electrocatalyst by controlling the atomic structure via the reaction environment and synthesis conditions.
Electrochemical carbon dioxide reduction reaction (CO2RR) is a promising approach to mitigate CO2 concentration and generate carbon feedstock. Recently, the (sub‐)nanometer design of catalyst structures has been revealed as an efficient means to control the reaction process through the local reaction environment. Herein, the synthesis of a novel tin oxide (SnOx) nanoparticle (NP) catalyst with highly controlled sub‐nanoscale interplanar gaps of widths <1 nm (SnOx NP‐s) is reported via the lithium electrochemical tuning (LiET) method. Transmission electron microscopy (TEM) and 3D‐tomo‐scanning TEM (STEM) analysis confirm the presence of a distinct segmentation pattern and the newly engineered interparticle confined space in the SnOx NP‐s. The catalyst exhibits a significant increase in CO2RR versus hydrogen evolution selectivity by a factor of ≈5 with 20% higher formate selectivity relative to pristine SnO2 NPs at −1.2 VRHE. Density functional theory calculations and cation‐size‐dependent experiments indicate that this is attributable to a gap‐stabilization of the rate‐limiting *OCHO and *COOH intermediates, the formation of which is driven by the interfacial electric field. Moreover, the SnOx NP‐s exhibits stable performance during CO2RR over 50 h. These results highlight the potential of controlled atomic spaces in directing electrochemical reaction selectivity and the design of highly optimized catalytic materials.
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