CuS Nanosheet Arrays for Electrochemical CO₂ Reduction with Surface Reconstruction and the Effect on Selective Formation of Formate

Abstract

Copper-based catalysts have shown excellent performance in electrochemical CO 2 reduction, but there has not been much study on copper sulfides. In our work, a simple and low-temperature chemical bath deposition method was used to fabricate CuS nanosheet arrays on brass, on which a Faradaic efficiency over 70% and a production rate over 50 mA•cm −2 for formate were obtained at a low potential of −0.7 V vs RHE when used as a catalytic electrode for CO 2 reduction. During the CO 2 reduction process, CuS nanosheets were partially reduced to Cu 0 and reconstructed to a nanowire network. It was found that residual S beneath the Cu 0 layer lowered the binding energies of intermediates HCOO* and *COOH, promoting their desorption and the successive formation of HCOOH or HCOO − , thus regulating the high selectivity of the product. This work provides a convenient and economical method for developing a highly active electrocatalyst for producing HCOOH in CO 2 electroreduction, and it is beneficial to understand the mechanism of enhanced selectivity to HCOO − for CuS electrode materials.

Energy conversion efficiency comparison of different aqueous and semi-aqueous CO2 electroreduction systems

“…To calculate the energy conversion efficiency for CO 2 electroreduction, we examined the literature using the CAS SciFinder software and calculated the efficiencies in 107 typical aqueous and semi-aqueous systems. 13–73 We selected the literature reports with a relatively high frequency of citations over the last 30 years. The pH of each CO 2 -saturated solution required for the calculation in this work was measured using an F-53 pH meter (HORIBA, Ltd).…”

“…3282 | Anal. Methods, 2022,14,[3280][3281][3282][3283][3284][3285][3286][3287][3288] This journal is © The Royal Society of Chemistry 2022 over the last 30 years were considered in this calculation. The pH of Naon was obtained from the literature 74.…”

Recent advancement in heterogeneous CO2 reduction processes in aqueous electrolyte

“…In 2021, Dou and his group bath-deposited CuS nanosheets on brass mesh, which on electrocatalysis was rapidly reconstructed to a nanowire network. 192 A DFT study suggested that the Cu(111) plane and residual sulfur (Raman data conrmed the presence of S residue) weakened the adsorption of HCOO* and *COOH intermediates; therefore, formate was formed without further reaction proceeding to CO. The electrocatalyst could provide a commendable high current density of 75 mA cm −2 at −0.7 V RHE with 67.8 AE 1% FE towards formate, while CO and CH 4 FE were less than 1%.…”

Multifunctional photo‐electrocatalysts of copper sulfides prepared via pulsed laser ablation in liquid: Phase formation kinetics and photo‐electrocatalytic activity

“…26 There are many recent works on Cu x S y applications in the newly emerging research fields created by the current economic and environmental issues, such as solar cells, photovoltaics, photocatalysts, photothermal agents, and electrocatalysts for the HER and CO 2 reduction reactions. [30][31][32][33][34][35][36][37][38] A few studies were performed to explore the applicability of Cu x S y for the HER and CO 2 reduction, which revealed that Cu-based materials could be used in energy storage devices and major CO 2 converters. 30,[39][40][41] In most previous works, Cu x S y was prepared by a conventional hydrothermal method, chemical bath deposition, and wet-chemical route.…”

“…In contrast, Cu 2 S does not exhibit any localized surface plasmon resonance (LSPR) 26 . There are many recent works on Cu x S y applications in the newly emerging research fields created by the current economic and environmental issues, such as solar cells, photovoltaics, photocatalysts, photothermal agents, and electrocatalysts for the HER and CO 2 reduction reactions 30‐38 . A few studies were performed to explore the applicability of Cu x S y for the HER and CO 2 reduction, which revealed that Cu‐based materials could be used in energy storage devices and major CO 2 converters 30,39‐41 …”