Alcoholamine-Grafted Zinc Oxide Enhances CO₂ Electroreduction at Elevated Temperatures

Abstract

Electrocatalytic reduction of CO 2 is an effective way to solve environmental issues. In this article, we report an inexpensive, readily available zinc oxide catalyst (TEA-ZnO) functionalized using alkanolamine, which is highly active and selective for the reduction of CO 2 to generate CO at elevated temperatures. Triethanolamine-modified zinc oxide (TEA-ZnO) shows ca. 88.8% CO Faradaic efficiency at −0.84 V vs RHE. The amine groups of triethanolamine could increase the adsorption capacity of CO 2 , expose more CO 2 -specific active sites, and mitigate the high-temperature decrease of CO 2 solubility, which enables TEA-ZnO to maintain high CO 2 selectivity in the temperature range of 0−60 °C.

Differential Pressure Across a Gas Diffusion Electrode Controls Efficiency of Liquid-Fed Electrolyzers for CO2 Electroreduction at Elevated Temperatures

“…While most lab-scale electrochemical CO 2 reduction (eCO 2 R) experiments are conducted at ambient temperatures (20–25 °C), maintaining such low temperatures on an industrial scale will become challenging due to Joule heating, which is the energy dissipated in the form of heat due to electrical resistances of the various system components . In recent years, interest in the effects of higher operating temperatures on the performance of electrochemical CO 2 reducing systems has increased. , For example, Löwe et al proposed that elevating the temperature could (1) favorably influence the required reduction potential, (2) accelerate transfer of CO 2 from gas to liquid and/or solid interface; (3) increase reaction kinetics of CO 2 reduction, and (4) lower the total cell resistance (Figure S1), resulting in a lower energy requirement. On the other hand, they stated that higher temperatures negatively impact the CO 2 solubility, could reduce the catalyst’s stability, and increase the reaction kinetics of the homogeneous acid–base reaction of CO 2 with (bi)­carbonate species in the electrolyte, resulting in a low carbon efficiency.…”