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Silica coating layer sustains low-coordinated active structure on CuO-derived catalysts for ampere-level CO2 electroreduction to C2+ products in acidic media.

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Title: Silica coating layer sustains low-coordinated active structure on CuO-derived catalysts for ampere-level CO2 electroreduction to C2+ products in acidic media.
Authors: Ma, Lushan1 (AUTHOR) lushan.ma@haut.edu.cn, He, Longfei1 (AUTHOR), Fan, Keyi2 (AUTHOR), Tan, Mengxi1 (AUTHOR), Wang, Jie1 (AUTHOR), Zheng, Yuanyuan1 (AUTHOR), Huang, Jin1 (AUTHOR), Zhang, Xueruo1 (AUTHOR), Zhao, Mengmeng1 (AUTHOR), Jiang, Sen1 (AUTHOR), Zhang, He1 (AUTHOR), Li, Bo1 (AUTHOR), Sun, Xuzhuo1 (AUTHOR), Chen, Jing1 (AUTHOR) chenjing0504@haut.edu.cn, Mei, Bingbao1,2 (AUTHOR) meibb@sari.ac.cn, Yang, Hui1,2 (AUTHOR) yangh@sari.ac.cn
Source: Applied Catalysis B: Environment & Energy. Aug2026, Vol. 391, pN.PAG-N.PAG. 1p.
Subjects: Silica films, Electrocatalysis, Electrode efficiency, Electrolytic reduction, Optical spectroscopy, Acid solutions, Hydrocarbons, Copper catalysts
Abstract: The electrochemical CO 2 reduction reaction (CO 2 RR) is a promising carbon resource recycling technology, with Cu-based catalysts uniquely capable of producing C 2+ products via C-C coupling. Acidic electrolytes mitigate carbonate formation issues of alkaline systems but induce severe hydrogen evolution reaction and Cu catalyst dissolution, making stabilizing Cu active sites a critical unresolved challenge. To address this, we designed porous CuO-based catalysts with tunable SiO 2 coating thickness to sustain low-coordinated active structures for acidic CO 2 RR. The optimized catalyst, featuring a ∼6 nm SiO 2 layer, achieves a C 2+ Faradaic efficiency of 78.2% and a high partial current density of 1182 mA cm−2 in an acidic medium (pH=1.9), significantly outperforming its pristine counterpart. In contrast, an excessively thick coating (∼12 nm) diminishes catalytic activity and triggers a distinct selectivity shift toward CH 4. This transition arises from two synergistic factors: restricted accessibility of internal Cu sites and the intrinsic CH 4 -producing activity of Cu2+ species anchored on the SiO 2 matrix. For the optimally SiO 2 -coated catalyst with enhanced C 2+ selectivity, mechanistic investigations via in situ X-ray absorption spectroscopy, in situ Raman spectroscopy and comprehensive post-reaction analyses reveal a SiO 2 -mediated anchoring-redeposition mechanism. The porous SiO 2 framework confines dissolved Cu species and directs their preferential redeposition into low-coordinated Cu active sites under CO 2 RR conditions, and the dynamic regeneration of these sites continuously enhances C-C coupling and C 2+ formation. This work clarifies the critical role of coating geometry in active site evolution, providing a rational design principle for industrial-scale acidic CO 2 RR systems. [Display omitted] • CuO@SiO 2 catalysts with tunable SiO 2 coating thickness were prepared for acidic CO 2 RR. • In situ XAS shows SiO 2 coating cannot ultimately prevent the CuO-core reduction. • C 2+ Faradaic efficiency and current density reach 78.2% and 1182 mA cm−2 respectively. • In situ spectroscopies observed the formation of low-coordinated CO 2 RR active sites. • SiO 2 -mediated anchoring-redeposition mechanism for active site formation is proposed. [ABSTRACT FROM AUTHOR]
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Abstract:The electrochemical CO 2 reduction reaction (CO 2 RR) is a promising carbon resource recycling technology, with Cu-based catalysts uniquely capable of producing C 2+ products via C-C coupling. Acidic electrolytes mitigate carbonate formation issues of alkaline systems but induce severe hydrogen evolution reaction and Cu catalyst dissolution, making stabilizing Cu active sites a critical unresolved challenge. To address this, we designed porous CuO-based catalysts with tunable SiO 2 coating thickness to sustain low-coordinated active structures for acidic CO 2 RR. The optimized catalyst, featuring a ∼6 nm SiO 2 layer, achieves a C 2+ Faradaic efficiency of 78.2% and a high partial current density of 1182 mA cm−2 in an acidic medium (pH=1.9), significantly outperforming its pristine counterpart. In contrast, an excessively thick coating (∼12 nm) diminishes catalytic activity and triggers a distinct selectivity shift toward CH 4. This transition arises from two synergistic factors: restricted accessibility of internal Cu sites and the intrinsic CH 4 -producing activity of Cu2+ species anchored on the SiO 2 matrix. For the optimally SiO 2 -coated catalyst with enhanced C 2+ selectivity, mechanistic investigations via in situ X-ray absorption spectroscopy, in situ Raman spectroscopy and comprehensive post-reaction analyses reveal a SiO 2 -mediated anchoring-redeposition mechanism. The porous SiO 2 framework confines dissolved Cu species and directs their preferential redeposition into low-coordinated Cu active sites under CO 2 RR conditions, and the dynamic regeneration of these sites continuously enhances C-C coupling and C 2+ formation. This work clarifies the critical role of coating geometry in active site evolution, providing a rational design principle for industrial-scale acidic CO 2 RR systems. [Display omitted] • CuO@SiO 2 catalysts with tunable SiO 2 coating thickness were prepared for acidic CO 2 RR. • In situ XAS shows SiO 2 coating cannot ultimately prevent the CuO-core reduction. • C 2+ Faradaic efficiency and current density reach 78.2% and 1182 mA cm−2 respectively. • In situ spectroscopies observed the formation of low-coordinated CO 2 RR active sites. • SiO 2 -mediated anchoring-redeposition mechanism for active site formation is proposed. [ABSTRACT FROM AUTHOR]
ISSN:09263373
DOI:10.1016/j.apcatb.2026.126674