Energy-efficient CO2/CO interconversion by homogeneous copper-based molecular catalysts

Abstract

Facile conversion of CO2 to commercially viable carbon feedstocks offer a unique way to adopt a net-zero carbon scenario. Synthetic CO2-reducing catalysts have rarely exhibited energy-efficient and selective CO2 conversion. Here, the carbon monoxide dehydrogenase (CODH) enzyme blueprint is imitated by a molecular copper complex coordinated by redox-active ligands. This strategy has unveiled one of the rarest examples of synthetic molecular complex-driven reversible CO2reduction/CO oxidation catalysis under regulated conditions, a hallmark of natural enzymes. The inclusion of a proton-exchanging amine groups in the periphery of the copper complex provides the leeway to modulate the biases of catalysts toward CO2 reduction and CO oxidation in organic and aqueous media. The detailed spectroelectrochemical analysis confirms the synchronous participation of copper and redox-active ligands along with the peripheral amines during this energy-efficient CO2reduction/CO oxidation. This finding can be vital in abating the carbon footprint-free in multiple industrial processes.

CCUS in India: bridging the gap between action and ambition

“…Development of catalysts has been another area of research in the Indian context [40][41][42]. This has been carried out in the context of CO 2 hydrogenation to produce formic acid and methanol.…”

Connecting Biological and Synthetic Approaches for Electrocatalytic CO2 Reduction

“…Although precise structural biomimics of FDH and CODH are not yet synthetically available, the inspiration derived from the active sites of enzymes fuels the preparation of bioinspired small molecule catalysts (Figures 2b-e). [6,15,62,63] The development of small molecule systems for CO 2 R is a strong and topical research area, annually yielding hundreds of new [87] (c) CODH-inspired [(bdt)Mo(O)S 2 CuCN] 2À , [63] (d) CODH-inspired [Fe(bpy NHEt PY 2 Me)], [15] (e) CODH-inspired [Cu(phenylazopyridine) 2 ], [88] (f) cobalt porphyrins, [72,89] (g) phosphonate-containing cobalt terpyridine, [90] (h) cobalt phthalocyanines, [91][92][93][94] and (i) iron porphyrins. [16] systems either operating in homogeneous conditions or, more recently, heterogenized onto electrodes.…”

“…[15,16] Incorporation of a Lewis acidic moiety near the catalytic center can mimic some of the key features of the enzymatic active site in NiFe-CODH enzymes and this strategy has demonstrated to benefit catalytic activity and CO selectivity in iron polypyridine complexes, and even enable catalytic CO 2 /CO bidirectionality in copper (phenylazo)pyridine complexes (Figure 2e). [15,88] The integration of cationic groups in iron porphyrins demonstrated that proximal coulombic interactions stabilized the negatively charged Fe-CO 2 intermediates, affording much lower overpotentials (220 vs � 800 mV) and high CO turnover frequencies (> 300 s À 1 ) compared to the unfunctionalized analogues (Figure 2i). [16] Beyond these examples, there are exciting opportunities to enhance small molecule catalysts' performance: (i) by incorporating enzyme-like features, e.g.…”

“…Figure 2. Structures of FDH enzyme's active site and small molecule catalysts: (a) active site of Desulfovibrio vulgaris Hildenborough (DvH) W-containing formate dehydrogenase (W-FDH), (b) FDH/CODH-inspired trans-[Mo(O)(2H-qpdt) 2 ] À ,[87] (c) CODH-inspired [(bdt)Mo(O)S 2 CuCN] 2À ,[63] (d) CODH-inspired [Fe(bpy NHEt PY 2 Me)],[15] (e) CODH-inspired [Cu(phenylazopyridine) 2 ],[88] (f) cobalt porphyrins,[72,89] (g) phosphonate-containing cobalt terpyridine,[90] (h) cobalt phthalocyanines,[91][92][93][94] and (i) iron porphyrins [16]. …”

Noble Metal Plasmon–Molecular Catalyst Hybrids for Renewable Energy Relevant Small Molecule Activation

“…54 Inspired by this natural and extremely effective catalyst design, continuous efforts have been put in by the scientific community to pursue efficient artificial CO 2 reduction. 55 Therefore, combining plasmonic nanomaterials with molecular catalysts is a new strategy to fabricate catalysts with high catalytic activity and selectivity. Molecular catalysts can act as functional mimics of natural metalloenzymes by incorporating unique enzymatic features in their framework.…”