Bimetallic In–Sn Core–Shell Catalyst Enabling Highly Efficient Electrocatalytic CO₂ Reduction to Formate

Abstract

Bimetallic catalysts are ideal candidates for boosting electrochemical CO 2 reduction reaction (CO 2 RR). However, these catalysts have largely relied on tedious synthesis technology and play electrolytic role with the help of a metal substrate or gas diffusion electrode. Herein, noble metal-free In−Sn nanoparticles (NPs) with a core−shell structure that contains a hybrid In−Sn core and native Sn-doped In 2 O 3 shell have been successfully grown on the copper foam by the potential-driven volume diffusion strategy. These NPs which spontaneously result in the formation of the In−Sn bimetallic interface by adjusting the element composition significantly boost the yield of CO 2 reduction into formate over a wide potential window (−0.77 to −1.17 V versus reversible hydrogen electrodes) compared with pure single-metal counterparts. The optimized In−Sn NPs deliver a great partial current density of 57.6 mA cm −2 and high faradaic efficiency of 97.0%, a remarkable performance in comparison to the state-of-the-art reported bimetallic catalyst. Such excellent performance is revealed via in situ Raman analyses and theoretical calculations, indicating that the unique structure of In−Sn NPs with the In−Sn bimetallic interface favorably regulates the reaction dynamics and facilitates the adsorption of the *OCHO intermediate.

Bilayer Porous Electrocatalysts for Stable and Selective Electrochemical Reduction of CO2 to Formate in the Presence of Flue Gas Containing NO and SO2

“…Similarly, the N 1s spectrum also did not show any NO-related peaks on the Bi/Cu foam catalyst surface (as shown in Figure S10e). In the case of In/Cu-f, the catalyst was exposed to pure CO 2 for 5 h. XPS characterization was performed before and after the reaction; the deconvoluted In 3d spectrum confirms that the In/Cu-f catalyst surface existed in both In(OH) 3 (445.03 and 452.57 eV) and In 2 O 3 (444.30 and 451.84 eV) states before CO 2 reduction , as shown in Figure d. However, after the reaction, the catalyst surface turned In (443 eV) and In 2 O 3 (451.3 eV).…”

Copper-Doped Tin Oxides Supported on Mesoporous Carbon Xerogel for Boosting the Electrochemical Reduction of CO2 to Formate in Bicarbonate Solution Coupled with CO2

“…One strategy to enhance catalyst properties is to utilize synergetic metals. Synergistic bimetallic electrocatalysts can have a promising avenue for improving activity and selectivity compared to their monometallic counterparts by fine-tuning their structure, morphology, and composition. − Bimetallic electrocatalysts, such as In–Bi, Zn–Bi, Sn–Cu, Bi–Eu, Pd–Bi, Bi–Sb, Sn–In, and Sn–Zn, have demonstrated to promote the conversion of CO 2 to formate/FA. Recently, Liu et al reported bimetallic Sn–Cu electrocatalyst showing over 80% FE; however, the performance was limited to 20 h and higher overpotential (−1.11 V vs RHE) .…”

Alkali Metal Ions Stabilizing Copper(I)–Sulfur Bonds for Efficient Formate Production from Electrochemical CO2 Reduction

“…It is also a promising candidate as a liquid hydrogen carrier with the capability of releasing gaseous hydrogen under mild conditions (e.g., at relatively low temperatures of 60–80 °C) . At present, several types of post-transition metal-based electrocatalysts, including Sn-, In-, Pb-, Pd-, and Bi-based electrocatalysts, have been developed for the CO 2 -to-formate conversion with successive progress. − Nevertheless, a large overpotential of up to 1.0 V is generally required to reach the industry-scale current densities (e.g., ≥200 mA cm –2 ), in addition to the pending issues of the insufficient Faradaic efficiency (FE), poor catalyst durability, and environmental toxicity. − …”