In Situ Dynamic Construction of a Copper Tin Sulfide Catalyst for High-Performance Electrochemical CO₂ Conversion to Formate

Abstract

Electrochemical reduction of CO 2 to produce fuels and chemicals is one of the most valuable approaches to achieve a carbon-neutral cycle. Recently, a diversity of catalysts have been developed to improve their intrinsic activity and efficiency. However, the dynamic evolution process and the in situ construction behavior of electrocatalysts under the working conditions are typically ignored. Here, we fully reveal the dynamic reduction process and phase transformation of a copper tin sulfide catalyst reconstructed by in situ reduction of the precatalyst Cu 2 SnS 3 and CuS during electrochemical CO 2 reduction. Furthermore, the reconstructed catalyst reaches an outstanding electrochemical CO 2 -to-formate conversion with a high Faradaic efficiency of 96.4% at an impressive production rate of 124889.9 μmol mg −1 h −1 under a partial current density of −241 mA cm −2 (−669.4 A g −1 ) in a flow-cell reactor. Theoretical calculations further demonstrate the strong charge interaction between the adsorbate and substrate to accelerate the charge transfer and decrease the formation energies of OCHO* and HCOOH* intermediates in the pathway of CO 2 to HCOOH, resulting in high selectivity for formate on the surface of the copper tin sulfide catalyst. This work paves the way for revealing the in situ dynamic process of the reconstructed catalyst and designing optimal catalysts with high catalytic activity and selectivity.

Integrating Electrochemical CO2 Reduction on α-NiS with the Water or Organic Oxidations by Its Electro-Oxidized NiO(OH) Counterpart to an Artificial Photosynthetic Scheme

“… In a similar note, the NiS/Ni 2 P heterostructure also retains its pristine morphology after HER, while after OER, an amorphous shell of NiO­(OH) formed . In another study, Cu 2 SnS 3 behaved as a pre-catalyst and a Cu–Sn alloy formation was precedent as the active species under the applied potential . Recent studies on CO 2 R with Cu 2 Se have shown that the presence of Se 2– with Cu­(I) resulted in ligand (Se)-to-metal (Cu) back-bonding, which increases the electron density on Cu to have better CO adsorption .…”

Heterogeneous Structure of Sn/SnO2 Constructed via Phase Engineering for Efficient and Stable CO2 Reduction

“…Of note, a substantial oxide phase persists in SnO 2 electrodes during cathodic reactions as manifested by in situ observations. , Consequently, multivalent Sn species including metallic Sn and its oxides are usually involved in SnO 2 -based catalysts, which can contribute synergistic effects for the catalytic process. − In particular, the metallic Sn and SnO 2 derived from identical precursors tend to join with each other, forming robust heterogeneous interfaces at the grain boundaries. Because of the unique local coordination environment at interfaces, the electronic structure of Sn atoms can be altered, thereby influencing the intrinsic catalytic activity. − In this regard, constructing a heterostructure of metallic Sn and SnO 2 with abundant interfacial boundaries is promising to fabricate an efficient catalyst for CO 2 -to-formate conversion, wherein a uniform distribution of Sn in the SnO 2 matrix is essential. However, aggregation of metallic Sn in situ derived from SnO 2 is thermodynamically more favorable, and modulating the dispersion of Sn in the nanoscale remains challenging.…”

Hydrothermal Synthesis of CuS Catalysts for Electrochemical CO2 Reduction: Unraveling the Effect of the Sulfur Precursor

“…Both experimental results (high partial current density of −241 mA/cm 2 and high HCOOH FE of 96.4%) and theoretical DFT calculation results evidenced that the strong charge interaction between the adsorbate and the substrate could enhance charge transfer, resulting in reduced energy for the generation of OCHO* and *COOH intermediates. Therefore, high formic acid selectivity was achieved in the catalytic reaction Figure b shows the partial current densities of the products of the different CuS catalysts.…”

“…Therefore, high formic acid selectivity was achieved in the catalytic reaction. 41 Figure 9b shows the partial current densities of the products of the different CuS catalysts. As indicated, all the catalysts show high CO partial current density (0.82∼1.70 mA/cm 2 ), and their HCOOH partial current density varies around 0.20∼0.30 mA/cm 2 .…”