Core-Shell ZnO@Cu2O as Catalyst to Enhance the Electrochemical Reduction of Carbon Dioxide to C2 Products

Abstract

The copper-based catalyst is considered to be the only catalyst for electrochemical carbon dioxide reduction to produce a variety of hydrocarbons, but its low selectivity and low current density to C2 products restrict its development. Herein, a core-shell xZnO@yCu2O catalysts for electrochemical CO2 reduction was fabricated via a two-step route. The high selectivity of C2 products of 49.8% on ZnO@4Cu2O (ethylene 33.5%, ethanol 16.3%) with an excellent total current density of 140.1 mA cm−2 was achieved over this core-shell structure catalyst in a flow cell, in which the C2 selectivity was twice that of Cu2O. The high electrochemical activity for ECR to C2 products was attributed to the synergetic effects of the ZnO core and Cu2O shell, which not only enhanced the selectivity of the coordinating electron, improved the HER overpotential, and fastened the electron transfer, but also promoted the multielectron involved kinetics for ethylene and ethanol production. This work provides some new insights into the design of highly efficient Cu-based electrocatalysts for enhancing the selectivity of electrochemical CO2 reduction to produce high-value C2 products.

Exploring Heterostructures of D-Block Metal Oxides Coupled to ZnO for the Electrochemical Reduction of CO2

“…The Cu-ZnO presents even faster kinetics for the CO formation, even though this catalyst also favors the *OCHO formation path . The Cu-ZnO GDE exhibits the highest internal exchange current density, associated with the lowest overpotential that Cu-ZnO structures are reported to induce for the ECR , and the contribution of Cu in CO formation . For the rest of the heterostructured GDEs, the slower kinetics are attributed to the enhanced HER rate arising from the exposed d-block metallic centers.…”

Recent insights on the use of modified Zn-based catalysts in eCO2RR

“…(b) FE of products on ZnO@4Cu 2 O; (c) the total current density of products on xZnO@yCu 2 O catalysts. 165 Copyright 2021. MDPI.…”

“…The introduction of GN was one of the effective methods to produce C 3 products from CO 2 , while tuning the structure of ZnO/Cu 2 O could also enhance the electrochemical reduction of CO 2 to C 2 products. For example, a catalyst with a ZnO core and a Cu 2 O shell was fabricated using a wet chemical method by Zhu et al 165 With the ZnO@4Cu 2 O catalyst, it was possible to make CO 2 firstly generate CO at the ZnO sites, and then the CO was coupled on to Cu 2 O to generate the C 2 products. By tailoring the synergy of the Cu and Zn oxides, a high FE of 49.8% was obtained for the C 2 products (ethylene: 33.5%, ethanol: 16.3%, as shown in Fig.…”

Hydrothermal fabrication of p‐Cu2O−n‐ZnO films and their properties for photodegradation and ultraviolet sensors

“…Their excellent electrochemical reduction of CO 2 was attributable to the core-shell structure and the enhanced kinetics for the formation of ethylene and ethanol. 48 Deo et al used a two-step chemical process to fabricate a heteronanobrush assembly (ZnO NRs grown on Cu 2 O nanoneedles) on a Cu substrate, and the sample exhibited enhanced field emission and photodegradation. 49 Kathalingam et al reported the hydrothermal fabrication of n-ZnO NRs on electrodeposited p-Cu 2 O films and studied the photosensing response of metallic -contact (Ag/ZnO NRs/Cu 2 O/ITO) and sandwich-type (ITO/ZnO NRs/Cu 2 O/ITO) devices.…”

“…employed a sol–gel method and an epitaxial shell growth approach to fabricate ZnO−Cu 2 O catalysts. Their excellent electrochemical reduction of CO 2 was attributable to the core‐shell structure and the enhanced kinetics for the formation of ethylene and ethanol 48 . Deo et al.…”