Electrochemical Reduction of CO₂ into Tunable Syngas Production by Regulating the Crystal Facets of Earth-Abundant Zn Catalyst

Abstract

The electrochemical reduction of CO to syngas with a tunable CO/H ratio is regarded as an economical and promising method for the future. Herein, a series of earth-abundant Zn catalysts with different crystal facet ratios of Zn(002) to Zn(101) in the bulk phase have been prepared on electrochemically polished Cu foam by the electrochemical deposition method. The Zn catalyst with more (101) crystal facets show good electrochemical activity for the CO reduction reaction (CORR) to CO and that with more (002) crystal facets favor the hydrogen evolution reaction. The linear relationship between the crystal facet ratio of Zn(101) to Zn(002) and the Faradaic efficiency (FE) of CORR to CO has been revealed for the first time. The prepared catalyst with more (101) facets show greater than 85% FE to syngas at -0.9 V (vs reversible hydrogen electrode) in aqueous electrolyte, with tunable CO/H ratios ranging from 0.2 to 2.31 that can be used in existing industrial systems. Meanwhile, the mechanism of electroreduction of CO on the Zn electrode has been studied by in situ infrared absorption spectroscopy. The highly selective role of the Zn(101) crystal facet in the CORR to CO has been evidenced by density functional theory calculations.

Microwave‐Assisted Synthesis of Copper‐Based Electrocatalysts for Converting Carbon Dioxide to Tunable Syngas

“…Other electrodes display a similar behavior (Figure S5‐S7). It is worth noting that the production rates of syngas at our electrodes are higher, as compared to other similar studies . To further investigate the stability behavior, 6 hours of electrolysis has been performed on the Cu‐5 electrode at −0.7 V. As shown in Figure e, the Cu‐5 electrode maintains a quasi‐steady current density.…”

Mn3O4@C Nanoparticles Supported on Porous Carbon as Bifunctional Oxygen Electrodes and their Electrocatalytic Mechanism

“…During the process of reaction, the intermediate species stabilized on the surface of the catalysts were tested by technique of attenuated total reflectance‐infrared absorption spectroscopy (ATR‐IRAS). The schematic diagram of the electrolytic cell is shown in the Supporting Information (Figure S12) . The parameter settings of the spectra were 64 coadded, 6 cm −1 resolution and 400–4000 cm −1 , respectively.…”

Sharp‐Tipped Zinc Nanowires as an Efficient Electrocatalyst for Carbon Dioxide Reduction

“…Researchers have revealed the high‐activity of noble‐metal electrodes (e.g., gold and silver) for CO 2 ‐to‐CO reduction, but the high cost limits the industrial applications. Zinc (Zn) is an earth‐abundant metal and recent studies have demonstrated the capacity of Zn as an efficient electrocatalyst for CO 2 reduction to primarily CO . Won et al.…”