Enhanced Electrochemical Reduction of CO₂to CO on Ag/SnO₂by a Synergistic Effect of Morphology and Structural Defects

Abstract

Silver (Ag)‐based materials are considered to be promising materials for electrochemical reduction of CO2 to produce CO, but the selectivity and efficiency of traditional polycrystalline Ag materials are insufficient; there still exists a great challenge to explore novel modified Ag based materials. Herein, a nanocomposite of Ag and SnO2 (Ag/SnO2) for efficient reduction of CO2 to CO is reported. HRTEM and XRD patterns clearly demonstrated the lattice destruction of Ag and the amorphous SnO2 in the Ag/SnO2 nanocomposite. Electrochemical tests indicated the nanocomposite containing 15% SnO2 possesses highest catalytic selectivity featured by a CO faradaic efficiency (FE) of 99.2% at −0.9 V versus reversible hydrogen electrode (vs RHE) and FE>90% for the CO product at a wide potential range from −0.8 V to −1.4 V vs RHE. Experimental characterization and analysis showed that the high catalytic performance is attributed to not only the branched morphology of Ag/SnO2 nanocomposites (NCs), which endows the maximum exposure of active sites, but also the special adsorption capacity of abundant defect sites in the crystal for *COOH (the key intermediate of CO formation), which improves the intrinsic activity of the catalyst. But equally important, the existed SnO2 also plays an important role in inhibiting hydrogen evolution reaction (HER) and anchoring defect sites. This work demonstrates the use of crystal defect engineering and synergy in composite to improve the efficiency of electrocatalytic CO2 reduction reaction (CO2RR).

Design and Synthesis of Ag‐based Catalysts for Electrochemical CO2 Reduction: Advances and Perspectives

“…Inspired by the interface characteristics, Geng and co-workers have prepared Ag/SnO 2 nanocomposites, containing the lattice destruction of Ag NPs and amorphous SnO 2 . [73] The Ag/SnO 2 nanocomposites containing 15% SnO 2 possess the highest FE CO of 99.2% at À 0.9 V (vs. RHE), and the value of FE CO is more than 90% at a wide potential range from À 0.8 V to À 1.4 V, suggesting superior selectivity. In addition, the experimental characterization and analysis have shown that amorphous SnO 2 can anchor the defect sites and inhibiting the HER.…”

Achieving Tunable Selectivity and Activity of CO2 Electroreduction to CO via Bimetallic Silver–Copper Electronic Engineering

“…Solid products were collected by centrifugation at 5000 r for 3 min, dry it in a 60 °C vacuum drying oven for 12 h and seal it for storage. For the synthesis of Ag 99 Cu 1 sample, 170 mg AgNO Electrochemical Test: According to the authors' previous test method, [53] briefly, the electrochemical experiments were carried out in H-cell with a Nafion 115 membrane as the separator. Each compartment contains 40 mL of 0.1 m KHCO 3 electrolyte (pH = 6.8).…”

“…According to the authors’ previous test method, [ 53 ] briefly, the electrochemical experiments were carried out in H‐cell with a Nafion 115 membrane as the separator. Each compartment contains 40 mL of 0.1 m KHCO 3 electrolyte (pH = 6.8).…”

Covalent Organic Frameworks Boost the Silver-Electrocatalyzed Reduction of CO2: The Electronic and Confinement Effect

“…3,4 Up to now, massive endeavors have been devoted to designing high-performance catalysts with Au, 5,6 Ag, 7,8 and Pd 9,10 as active sites for CO 2 -to-CO transformation. Further studies have demonstrated that the adjustment of the coordination number of the active sites and the local electronic structure through crystal facets, 11 grain boundaries, 12,13 and defects 14,15 at the nanoscale and the regulation of mass transfer of substrates and electrochemically active surface area through the particle size, 16,17 morphology, 7,18 and porosity 19,20 at the mesoscale greatly influence the catalytic activity and selectivity.…”

“…Electrochemical reduction reaction of CO 2 (CO 2 RR) is an ideal solution to alleviate the greenhouse effect among different CO 2 fixation methods for its high environmental compatibility. , Among various CO 2 RR pathways, electrochemical CO 2 reduction to CO is considered one of the most promising approaches due to its considerable technical and economic feasibility. , Up to now, massive endeavors have been devoted to designing high-performance catalysts with Au, , Ag, , and Pd , as active sites for CO 2 -to-CO transformation. Further studies have demonstrated that the adjustment of the coordination number of the active sites and the local electronic structure through crystal facets, grain boundaries, , and defects , at the nanoscale and the regulation of mass transfer of substrates and electrochemically active surface area through the particle size, , morphology, , and porosity , at the mesoscale greatly influence the catalytic activity and selectivity.…”