Organic, Organometallic and Bioorganic Catalysts for Electrochemical Reduction of CO₂

Abstract

A broad review of homogeneous and heterogeneous catalytic approaches toward CO2 reduction using organic, organometallic, and bioorganic systems is provided. Electrochemical, bioelectrochemical and photoelectrochemical approaches are discussed in terms of their faradaic efficiencies, overpotentials and reaction mechanisms. Organometallic complexes as well as semiconductors and their homogeneous and heterogeneous catalytic activities are compared to enzymes. In both cases, their immobilization on electrodes is discussed and compared to homogeneous catalysts in solution.

Recent Trends, Benchmarking, and Challenges of Electrochemical Reduction of CO2 by Molecular Catalysts

“…[20,21] When electrochemistry is coupled in situ or ex situ to spectroscopic measurements, the results can be used to uncover the intrinsic mechanism and to infer deep mechanistic insights about the involved catalytic active species enabling a quantitative assessment and comprehensive understanding of the thermodynamic and kinetic parameters that govern the overall catalytic cycle. [26,27] This area of research has over the past couple of years been accelerating, with novel catalysts achieving excellent performances and durability. [25] The ability to control chemical functionality of molecular catalysts at nanoscale allows to establish the relationships between selectivity and catalyst structure.…”

“…In this aspect, the structure modification by synthetic chemistry enables rigorous catalytic control and any limitations diagnosed to be overcome by catalyst reengineering which is promising in performing on demand process conversion routes which minimize or eliminate by-products, while maximizing final product purity/Faradaic efficiency (FE) or selectivity. [26,27] This area of research has over the past couple of years been accelerating, with novel catalysts achieving excellent performances and durability. [28,29] Thus, in the present contribution, we review what has been achieved in this area in its very recent past, by focusing on the most promising catalyst results of developments in context of CO 2 reduction with discussion on their performance, efficiency, and stability data.…”

“…The ability to control chemical functionality of molecular catalysts at nanoscale allows to establish the relationships between selectivity and catalyst structure. In this aspect, the structure modification by synthetic chemistry enables rigorous catalytic control and any limitations diagnosed to be overcome by catalyst reengineering which is promising in performing on demand process conversion routes which minimize or eliminate by‐products, while maximizing final product purity/Faradaic efficiency (FE) or selectivity …”

Homogeneous and heterogeneous molecular catalysts for electrochemical reduction of carbon dioxide

“…62 This has been demonstrated previously using amino and pyridine-substituted compounds for electrochemical CO 2 RR in both homogeneous and heterogeneous media. 18,[63][64][65][66][67][68][69] Various catalysts have been developed as both homogeneous molecular catalysts 16,18,[70][71][72][73][74][75][76][77] and heterogeneous solid-state catalysts, 22,40,78 such as metal alloys, 79,80 non-metal catalysts 81 and single atoms. 82 The identity of the metal electrodes have also been shown to play a role in the product distribution.…”

Homogeneous hydrogenation of saturated bicarbonate slurry to formates using multiphase catalysis

“…3 Among the various CO 2 utilization strategies, its chemical conversion to C 1 building blocks have been the focus of intense research effort over the last decades. [4][5][6] The common utilization routes rely on CO 2 reduction that can be performed electrochemically 7,8 or utilize molecular hydrogen as a reducing agent. 9,10 The latter can be further split into heterogeneous processes that mainly target methanol as a main product and homogeneous reduction protocols that typically produce formic acid and its salts.…”