Formic Acid Electro‐Synthesis by Concurrent Cathodic CO₂ Reduction and Anodic CH₃OH Oxidation

Abstract

The electrochemical conversion of carbon dioxide into energy‐carrying compounds or value‐added chemicals is of great significance for diminishing the greenhouse effect and the efficient utilization of carbon‐dioxide emissions, but it suffers from the kinetically sluggish anodic oxygen evolution reaction (OER) and its less value‐added production of O2. We report a general strategy for efficient formic‐acid synthesis by a concurrent cathodic CO2 reduction and anodic partial methanol‐oxidation reaction (MOR) using mesoporous SnO2 grown on carbon cloth (mSnO2/CC) and CuO nanosheets grown on copper foam (CuONS/CF) as cathodic and anodic catalysts, respectively. Anodic CuONS/CF enables an extremely lowered potential of 1.47 V vs. RHE (100 mA cm−2), featuring a significantly enhanced electro‐activity in comparison to the OER. The cathodic mSnO2/CC shows a rather high Faraday efficiency of 81 % at 0.7 V vs. RHE for formic‐acid production from CO2. The established electrolyzer equipped with CuONS/CF at the anode and mSnO2/CC at the cathode requires a considerably low cell voltage of 0.93 V at 10 mA cm−2 for formic‐acid production at both sides.

Anode Catalysts in CO2 Electrolysis: Challenges and Untapped Opportunities

“…The rest of the cited studies were carried out in stagnant electrolytes, employing a membrane-separated H-cell configuration. The list of both the studied substances and electrocatalysts are more diverse here: in addition to glycerol, 167 HMF, 167 , 170 methanol, 168 ethanol, 169 isopropanol, 171 1-phenylethanol, 171 4-methoxybenzyl alcohol, 171 and benzyl alcohol 162 were tested as potential oxidizable substance candidates (sometimes called fuels). Both heterogeneous (noble metals such as Pt and Pd, metal oxides such as CuO nanosheets and NiO nanoparticles, and a redox mediator (STEMPO)) and dissolved 162 electrocatalysts were considered.…”

Concentrated formate produced through co‐electrolysis of CO2 and methanol in a zero‐gap electrolyzer

“…Furthermore, MOR could produce HCOO À with high selectivity under alkaline condition through catalyst design. 22,32,36 Thus, we designed a CO 2 RR coupled with MOR system in zero-gap CO 2 electrolyzers, where HCOO À product of CO 2 RR can fast migrate to anode through an AEM and is then merged with formate generated by MOR at anode (Figure 1D). More important, we can obtain HCOO À product with high concentrations by cyclic accumulation, which will greatly reduce the downstream separation cost.…”

Co–Ni–P Nanoneedle Array Heterostructures with Built-In Potential for Selective Methanol Oxidation Coupled with H2 Evolution

“…Methanol as one of the most important C1 resources is cheap (about 350 € per ton) and abundant . Formate, the selected oxidation product of methanol, is an important industrial intermediate (about 539 € per ton) that finds extensive application in chemical industry fields (pharmaceutical, rubber, dyestuff, and hydrogen storage). , However, the traditional technology for formate production involves complicated processes and serious pollution issues . It would be very interesting to integrate the methanol oxidation reaction (MOR) with the HER under ambient conditions to gain high-purity H 2 and value-added formate.…”