Electrocatalytic reduction of CO₂by thiophene-substituted rhenium(i) complexes and by their polymerized films

Abstract

Three novel thiophene substituted bipyridine ligands and their corresponding rhenium complexes were synthesized and tested for the electrocatalytic reduction of CO2. Two complexes underwent oxidative electropolymerization on a glassy carbon electrode (GCE) surface. The conductive polymers chemically deposited on the GCE allow electron transport from the surface to the polymer-attached rhenium catalytic center in contact with the solution. The chemically modified electrodes show significant catalytic activities for CO2 reduction, and moderate relative higher stabilities when compared with the homogeneous solution counterparts.

Organic, Organometallic and Bioorganic Catalysts for Electrochemical Reduction of CO2

“…Nervi andc o-workers investigated three thiophened erivatives (Figure 23) with Re pendant groupsa sc on- www.chemphyschem.org jugated polymer building blocks for electrocatalytic reduction of CO 2 . [113] The authors investigated the catalytic properties of monomers 2 and 3 as well as their corresponding polymers. The monomers showed adecrease in the catalytic activity after 60 min.…”

“…Af aradaic efficiency of 84 %w as achieved with ap olymer of 2 and3 4% with ap olymer of 3 at ap otential of À2100 mV (vs. Fc/Fc + ). [113] Apaydin et al investigated polythiophene structures with pendantc atalyst groups for the photoelectrochemicalr eduction of CO 2 . [114] This is of particulari nterest because previous studies addressing the use of conjugated polymers lacked the information on how ap -type materialc an drive electrons through its backbone unlesst unneling wast he main driving force.…”

“…Threegenerations of conjugated polymers.a )Polymerswith good conductivity but low processability;b)polymers with alkyl chains allowing solubility and hence processability;c)polymers with improved and/ or new physical/chemical and catalyticp roperties.R eproducedw ith permission from Ref [113]…”

“…Structureso f[Re(bpy)(CO)3 Cl]-functionalized thiophene monomers. Reproduced with permission from Ref [113]…”

Highly Photoactive Polythiophenes Obtained by Electrochemical Synthesis from Bipyridine-Containing Terthiophenes

“…In this way, light absorption is guaranteed for both cell compartments and a sufficient driving force would also be assured to activate the molecular catalyst responsible for CO 2 reduction. Furthermore, Re complexes with a terthiophene-containing ligand have demonstrated high activity in CO 2 reduction, even when immobilized, with remarkable turn-over number larger than 500, demonstrating the feasibility of a polythiophene-based photocathode for CO 2 reduction [34].…”