Robust Electroreduction of CO₂ at a Poly(4‐vinylpyridine)–Copper Electrode

Abstract

The development of efficient and robust catalysts based on earth‐abundant and nontoxic materials is critical for the viability of the electrocatalytic conversion of CO2 into useful chemicals. Herein, we report a new class of electrocatalysts with incorporated mechanisms of their stabilization. A Cu electrode coated with a poly(4‐vinyl pyridine) film synthesizes formate at a faradaic efficiency of 40 % at an overpotential of −0.67 V, and its catalytic activity does not degrade after 30 h of operation. We attribute the outstanding catalytic properties of the new hybrid material to the formation of Cu–polymer complexes, as well as to new intrinsic mechanisms of the electrode stabilization offered by the N‐heteroaromatic polymer. This is the first report of CO2 electroreduction with copper–N‐heteroaromatic ligand complexes. More generally, our study offers a new simple strategy to design and prepare robust CO2 reduction electrocatalysts based on earth‐abundant metals.

CO2 electroreduction on P4VP modified copper deposited gas diffusion layer electrode: pH effect

“…Early formic acid formation at these pH levels may be closely related with the change in the buffer strength of electrolyte on the electrode surface or proton stabilization or donation effect of P4VP [49] that encapsulates or neighbors copper catalyst centers. In fact, the results shown here are in agreement with high formic acid selectivity reported on P4VP modified copper foil electrode in 0.1 M KHCO 3 electrolyte (pH 6.8) [41]. At pH 1.46, no formic acid was detected.…”

“…Figure 8 shows that both faradaic efficiency and formic acid concentration increased after P4VP loading at pH 3.87. This means that P4VP could actively participate in formic acid production route by decoupled proton electron transfer mechanism at this pH level [41]. Highest formic concentration (2.6 mM) and highest faradaic efficiency (15 %) was also attained at pH 3.87.…”

“…Comparison of current densities of unmodified and P4VP modified Cu/GDL in both blank and CO 2 -purged electrolytes also indicates that P4VP could induce mass transport resistance unlike when it is loaded on planar surfaces like copper foil [41]. We believe that this is due to the blocking effect of P4VP on the electrode surface other than the pH sensitivity.…”

RETRACTED ARTICLE: An overview of CO2 electroreduction into hydrocarbons and liquid fuels on nanostructured copper catalysts

“…Nanostructured metals, a representative class of nanostructured materials, have attracted huge attention over the last decade due to their intriguing properties and promising potential for various typical applications, such as catalysis and energy conversion/storage systems (21)(22)(23)(24)(25)(26)(27)(28)(29). Due to their unique properties, such as enlarged specific surface area and 2-and 3-dimensional interpenetrating structures, nanostructured metals can provide easy diffusion pathways to the substrate to access the electrolyte ions and a large number of active sites for the catalysis, leading to a faster reaction with high efficiency (30)(31)(32). Recently, a very promising nanostructured material, namely, copper foam with hierarchical porosity, was reported for the reduction of CO 2 with high rate and selectivity for hydrocarbons (33).…”

Sustainable Membrane‐Coated Electrodes for CO2 Electroreduction to Methanol in Alkaline Media

“…[4,27] Also, high alkaline pH has been observed to influence CO 2 reduction on Cu catalyst surfaces, due to the hydroxide ions role in modulating the catalyst surface and suppressing the HER. Protective membrane layers composed of metal oxides [39,40] have been proposed for HER and Methanol Oxidation Reaction, and conductive polymers [41][42][43][44][45] have been studied for the CO 2 electroreduction at chemistry laboratories, where the polymer both protects the catalytic layer and boosts the ion transport to the active sites, thus reducing the required over potentials [42,46] and slightly improving the efficiency of the CO 2 electrochemical reduction in different media. In CO 2 electrolyzers working in alkaline conditions, OH À ions rapidly react in the presence of CO 2 to form HCO 3 À and CO 3 2À but the lower mobility of the latter ions compared to OH À usually inhibit ion transport and reduce CO 2 reduction efficiency.…”