Nonprecious Catalyst for Three-Phase Contact in a Proton Exchange Membrane CO₂ Conversion Full Cell for Efficient Electrochemical Reduction of Carbon Dioxide

Abstract

Development of a cost-effective and highly efficient electrocatalyst is essential but challenging in order to convert carbon dioxide to value-added chemicals at ambient conditions. In the current work, the activity of a full electrochemical cell has been demonstrated, utilizing a proton exchange membrane CO 2 conversion cell that can selectively convert carbon dioxide to a value-added chemical (formic acid) at room temperature and pressure. A cost-effective, nonprecious-metal-based electrocatalyst, nitrogen-doped carbon nanotubes encapsulating Fe 3 C nanoparticles (Fe 3 C@ NCNTs), has been reported to exhibit superior catalytic activity toward the electrochemical CO 2 reduction reaction (CO 2 RR). A facile one-step synthesis procedure has been undertaken to synthesize Fe 3 C@NCNTs. CO 2 adsorption takes place via sharing of charge between the nucleophilic anchoring site (Fe 3 C) and the electrophilic C site of CO 2 , as shown by the DFT studies. The porous architecture, unique tubular structure, high graphitization degree, and appropriate doping of the Fe 3 C-encapsulating NCNTs allow better three-phase contact of CO 2 (gas), H 2 O (liquid), and catalyst (solid), which can enhance the electrocatalytic activity of the cell, as demonstrated by the experimental findings. The cell was tested under a continuous flow of CO 2 gas and has been demonstrated to produce a good amount of formic acid (HCOOH). The production of formic acid was examined by utilizing UV−vis spectroscopy and high-performance liquid chromatography (HPLC). A series of designed experiments disclosed that the maximum yield of formic acid was as high as 90% with Fe 3 C@NCNTs as both anode and cathode catalysts. Technology to scale up the reduction procedure has also been proposed and shown in this particular work. These unique observations open a route for the development of cost-effective and highly active platinum-free electrocatalysts for the CO 2 RR.

Selective electrochemical reduction of CO2 on compositionally variant bimetallic Cu–Zn electrocatalysts derived from scrap brass alloys

“…Another challenge is by converting CO 2 directly into CH 4 one faces high overpotentials, which can be a significant source of inefficiency 16 . Techno-economic models suggest an indirect pathway for the production of hydrocarbons via carbon monoxide (CO) can be more practical in light of commercial viability 17 – 19 . Moreover, well-established industrial processes, such as Fischer–Tropsch, utilize direct CO-based feedstock 20 .…”

Electroreduction of CO2: Advances in the Continuous Production of Formic Acid and Formate

“…144 Furthermore, porous support materials can effectively increase the reaction-specific surface (based on carbon materials). For example, carbon nanotubes employed as support for catalyst nanoparticles, 149,175,178 and other complex structures based on the metal−organic frames with different metallic catalysts, such as Bi 157,158 and In, 186 have demonstrated great performance. These structures achieved FEs of up to 90% for the target product at current densities >200 mA• cm −2 .…”

Fundamentals of Gas Diffusion Electrodes and Electrolysers for Carbon Dioxide Utilisation: Challenges and Opportunities

“…Originally, CO 2 reduction at gas diffusion electrodes was considered a three-phase interface process, considering that CO 2 conversion took place at the gas-liquid-solid interface of CO 2 , electrolyte, and catalyst, respectively [63]. No explicit evidence was provided in support of this theory, but since then, it has been referenced in various research papers [135,[165][166][167]. Burdyny et al have recently proposed a different perspective in support of a two-phase reaction interface involving dissolved CO 2 as the reagent [58].…”

“…theory, but since then, it has been referenced in various research papers [135,[165][166][167]. Burdyny et al have recently proposed a different perspective in support of a two-phase reaction interface involving dissolved CO2 as the reagent [58].…”