Toward Excellence of Transition Metal‐Based Catalysts for CO₂ Electrochemical Reduction: An Overview of Strategies and Rationales

Abstract

Rational modulations of interactions between catalyst surface and intermediates are challenging but extremely important to achieve an efficient and selective electrochemical CO 2 reduction (CO 2 R). Current CO 2 R catalyst design remains inefficient because of a gap between existing practical design paradigms and theoretical studies in catalysis. This review attempts to mitigate this gap through a critical discussion of the correlations between recent strategies to develop transition metal-based catalysts and the underlying rationales and mechanisms. These strategies include surface engineering, the introduction of heterogeneous atoms, and dimension control, and can be implemented by tactics such as controlling catalysts surface facets, surface tethering, alloying, inducing strains, oxide derivation, molecular scaffolding, and nanostructuring. Just how these tactics are able to tailor the electronic structure, adsorption geometry, density of active sites, and local environment of catalyst to achieve an efficient and selective CO 2 R, is described. This review concludes with a discussion of the key research needs in this field such as the surface proton formation and transfer involved in CO 2 R, the roles of mass-transfer or electrode kinetics in CO 2 R catalysis, development of robust, standardized catalyst testing protocols, and application of machine learning and high-throughput experiment to accelerate catalysts screening processes.

Recent Progress in Electrocatalytic Methanation of CO2 at Ambient Conditions

“…Alloying is an effective pathway to tune the electronic properties of a host element through introducing a foreign element. [95] Changes of the electronic properties can reflect the changing of the binding energies of *H and various intermediates formed in the electrochemical CO 2 RR. [82,96] Therefore, forming an alloy can enhance catalytic activity and selectivity of CO 2 RR through tuning the binding strength of intermediates, resulting in an enhanced reaction kinetics for CO 2 reduction.…”

Fundamentals of Gas Diffusion Electrodes and Electrolysers for Carbon Dioxide Utilisation: Challenges and Opportunities

“…Although aqueous-fed electrolysers can provide critical information on key factors affecting CO 2 R-such as catalyst composition, structure, surface tailoring, and electrolysis environment-their commercialisation is inconceivable since industrial application is only viable at high conversion rates, i.e., current densities above 250 mA/cm 2 . Aqueous-fed electrolysers cannot fulfil this requirement due to limited CO 2 mass transport restricting current densities to values up to 35 mA/cm 2 , for two-electron reduction processes in bulk liquid phase [58,59]. In particular, CO 2 R kinetics in batch-type electrolysis is limited by the slow diffusion and low solubility of CO 2 in the aqueous media.…”

Nanostructured Cobalt‐Based Electrocatalysts for CO2Reduction: Recent Progress, Challenges, and Perspectives

“…A Tafel slope value of around 40 mV dec −1 suggests that the rate-determining step is the formation of *CO (Equation 21, Figure 2b) that is following the *COOH formation during ECO 2 RR to CO. [18] In recent years, researchers have put great effort into fabricating the highly efficient electrocatalysts for ECO 2 RR. Many reviews have discussed different aspects in the field, such as heterogeneous molecular catalysts, [31] atomic-level nanostructured catalysts, [32] catalyst design engineering, [33] carbon-based materials, [34] TM-based catalysts, [35] and Cu-based materials [36] . Among TM elements, Co with promising catalytic activity shows great potential toward CO 2 RR.…”