Hydrogen-Mediated Synthesis of 3D Hierarchical Porous Zinc Catalyst for CO₂ Electroreduction with High Current Density

Abstract

Zn-based catalyst is promising for electrochemical CO2 reduction (CO2RR) because of the abundant reserves and good activity. However, a major challenge still remains in simultaneously achieving both large current density and high Faradaic efficiency. Herein, we report a three-dimensional porous Zn catalyst (HP-Zn) for CO2RR via a simple hydrogen-mediated method, where hydrogen gas bubbles have been utilized as soft templates to generate a series of hierarchical pores in the sample. Benefiting from the high specific surface area (97.2 m2 g–1) and rich mesoporous structure, the as-prepared HP-Zn catalyst displays excellent catalytic activity with a maximum CO Faradaic efficiency of 91.3%, corresponding to a current density of −10.0 mA cm–2, as well as long-term stability, demonstrating a promising potential for the practical application of CO2RR.

Zn-Based Catalysts for Selective and Stable Electrochemical CO2Reduction at High Current Densities

“…The NP- and NS-ZnO-GDEs exhibit even lower contact angle values after ECR. The conversion of the oxide phase to a metallic phase is a non-Faradaic process that has been shown to be responsible for the change in the catalyst surface area. , Although the catalyst morphology changes during ECR, the ZnO-NR catalyst undergoes changes that tend to maintain a uniform catalyst layer that retains its hydrophobic properties to some extent (Figure S6E).…”

Layer-Stacked Zn with Abundant Corners for Selective CO2 Electroreduction to CO

“…(d) Catalytic stability for layer-stacked Zn. (e) Stability comparison of Zn-based catalysts, such as Zn dendrites, LiET Zn, ZnO nanosheets/Zn, 3D hierarchical porous Zn, porous Zn, hexagonal Zn nanoplates, hexagonal Zn, sharp-tipped Zn nanowires, and the layer-stacked Zn in this work. (f) Reactivation of layer-stacked Zn.…”

“…CO 2 reduction experiments were carried out in an H-type electrochemical cell comprising working and counter-electrode compartments, separated by a proton exchange membrane. In the working compartment, the 33 LiET Zn, 52 ZnO nanosheets/Zn, 53 3D hierarchical porous Zn, 54 porous Zn, 34 hexagonal Zn nanoplates, 38 hexagonal Zn, 35 sharp-tipped Zn nanowires, 55 catholyte was continuously purged with CO 2 at a constant flow rate and vented directly into the gas-sampling loop of a gas chromatograph (GC) for the periodic quantification of the gasphase products.…”

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

“…Copyright 2017. Elsevier Inc. (c) CV curves for the HP-Zn catalyst at various scan rates; (d) charging current density differences plotted against scan rates 56. Copyright 2021.…”