Efficient bioelectrocatalytic CO2 reduction on gas-diffusion-type biocathode with tungsten-containing formate dehydrogenase

Abstract

A new gas-diffusion-type biocathode was constructed for carbon dioxide (CO 2) reduction. In this work, tungsten-containing formate dehydrogenase (FoDH1), which is a promising enzyme for interconversion of formate and CO 2 , was used as a catalyst and was absorbed on a Ketjen Black (KB)-modified electrode. We used 1,1'-trimethylene-2,2'-bipyridinium dibromide as a mediator, and the hydrophobicity of the FoDH1-absorbed electrode was optimized according to the weight ratio of the polytetrafluoroethylene binder to KB. We achieved cathodic current densities of about 20 mA cm −2 under mild and quiescent conditions (neutral pH, atmospheric pressure, and room temperature).

Molybdenum-Dependent Formate Dehydrogenase for Formate Bioelectrocatalysis in a Formate/O2Enzymatic Fuel Cell

“…2 Formic acid is also highly soluble in water and is liquid at room temperature. 2 Formate dehydrogenase (FDH) is an enzyme which can catalyze the reversible oxidation of formate to CO 2 according to the reaction: [3][4][5][6] HCOO − ← → CO 2 + 2e − + H + and different FDHs are classified into two major classes: metalindependent (nicotinamide adenine dinucleotide (NAD)-dependent enzymes) and metal-dependent enzymes. NAD-dependent FDHs have been used in the past for formic acid/formate EFCs, but they have been plagued by the poor electrooxidation of NADH and poor stability of NAD + .…”

Recent Enzymatic Electrochemistry for Reductive Reactions

“…demonstrated a bioelectrocatalytic system for HCOO − oxidation and CO 2 reduction with high catalytic current densities and small overpotentials by using FoDH1 as a bioelectrocatalyst and MV derivatives were used as electron mediators . Another article from the same team using the same enzyme reported MET with freely diffusing 1,1′‐trimethylene‐2,2′‐bipyridinium dibromide (PBV) and showed cathodic current densities of about 20 mA cm −2 . In contrast to MV (MV .+ /MV 2+ , E 0 ′=−0.45 V vs .…”

Strategies for Bioelectrochemical CO2 Reduction

“…In another DET design, a gold nanoparticle‐ embedded Ketjenblack‐modified glassy carbon electrode treated with 4‐mercaptopyridine facilitated the correct orientation of W‐FDH, improving interfacial electron transfer kinetics . The use of an artificial redox mediator (1,1′‐trimethylene‐2,2′‐bipyridinium dibromide) enabled highly efficient CO 2 reduction with current densities of approximately 20 mA cm −2 using a gas diffusion biocathode . For CO 2 reduction, the most exceptional metal‐dependent FDH yet discovered is found in Syntrophobacter fumaroxidans with a turnover rate of 282 s −1 , two orders of magnitude faster than any known catalyst for the same reaction .…”

“…[23] The use of an artificial redox mediator (1,1'-trimethylene-2,2'bipyridinium dibromide) enabledh ighly efficient CO 2 reduction with current densities of approximately 20 mA cm À2 using a gas diffusion biocathode. [24] For CO 2 reduction,the most exceptional metal-dependent FDH yet discoveredi sf ound in Syntrophobacter fumaroxidans with at urnover rate of 282 s À1 ,t wo orders of magnitude faster than any known catalyst for the same reaction. [25] When adsorbed to ap yrolytic graphite edge electrode, this FDHf acilitates CO 2 reduction with al ow onset potentialo fÀ0.41 Vv s. SHE with near 100 %f aradaic efficiency ( Figure 1B).…”