Electrochemical Reduction of CO₂ to Formate on Glacial Acetic Acid-Refluxed Pd Nanoclusters

Abstract

The electrochemical reduction of CO 2 (CO 2 ER) to formate on Pd has attracted the broad interest in the chemical energy storage/ conversion systems. However, this reaction is commonly constrained to a narrow potential range (positive to −0.25 V (vs RHE)) and low reactivity due to CO poisoning on the Pd surface. Here, the Pd/carbon catalyst was refluxed in glacial acid (A-Pd/XC72) to enhance the CO tolerance and the formate forming activity of Pd. The results demonstrate that the faradaic efficiency (F.E.) and charges for formate formation are over 95% and 60 coulombs over 1 h of electrolysis at −0.3 V (vs RHE) in the CO 2 -saturated 0.5 M KHCO 3 solution, which are 4 times as high as original Pd/XC72. The F.E. of formate formation remains around 80% when the applied potential is shifted to −0.5 V (vs RHE). Both i-t and cyclic voltammetric (CV) analyses indicate the low rate of CO self-poisoning on A-Pd/XC72. The UV-vis spectra recording the surface change of Pd NPs in the glacial acetic acid suggest the adsorption of acetate species onto the surface of Pd, which are decomposed into carbonaceous species after heating, enhancing the CO 2 ER selectivity toward the formate formation.

Thiophene Functionalized Porphyrin for Electrochemical Carbon Dioxide Reduction

“…4,5 Traditional catalytic techniques for CO 2 absorption, conversion and activation still have several limitations, such as high energy demands for transferring CO 2 molecules to active sites, low conversion rates for obtaining high-value carbon containing compounds, and so on. To convert CO 2 into other compounds, a variety of techniques, such as biocatalysis, 6 organic reactions lead to chemical transformations, 7 electrocatalytic or photocatalytic reduction [8][9][10][11] etc., have been used.…”