Recent Progress in Two-Dimensional Materials for Electrocatalytic CO2 Reduction

Abstract

Electrocatalytic CO2 reduction (ECR) is an attractive approach to convert atmospheric CO2 to value-added chemicals and fuels. However, this process is still hindered by sluggish CO2 reaction kinetics and the lack of efficient electrocatalysts. Therefore, new strategies for electrocatalyst design should be developed to solve these problems. Two-dimensional (2D) materials possess great potential in ECR because of their unique electronic and structural properties, excellent electrical conductivity, high atomic utilization and high specific surface area. In this review, we summarize the recent progress on 2D electrocatalysts applied in ECR. We first give a brief description of ECR fundamentals and then discuss in detail the development of different types of 2D electrocatalysts for ECR, including metal, graphene-based materials, transition metal dichalcogenides (TMDs), metal–organic frameworks (MOFs), metal oxide nanosheets and 2D materials incorporated with single atoms as single-atom catalysts (SACs). Metals, such as Ag, Cu, Au, Pt and Pd, graphene-based materials, metal-doped nitric carbide, TMDs and MOFs can mostly only produce CO with a Faradic efficiencies (FE) of 80~90%. Particularly, SACs can exhibit FEs of CO higher than 90%. Metal oxides and graphene-based materials can produce HCOOH, but the FEs are generally lower than that of CO. Only Cu-based materials can produce high carbon products such as C2H4 but they have low product selectivity. It was proposed that the design and synthesis of novel 2D materials for ECR should be based on thorough understanding of the reaction mechanism through combined theoretical prediction with experimental study, especially in situ characterization techniques. The gap between laboratory synthesis and large-scale production of 2D materials also needs to be closed for commercial applications.

Exploring anodes for calcium-ion batteries

“…2D carbon materials have been applied to many forms of technology, including that of carbon capture, catalysis and most crucially, metal ion batteries (MiB). 73,74 Graphite remains the most stable and fundamental carbon anode but there have been Li + ion batteries with carbon anode allotropes such as popgraphene, pentagraphene, c-graphene, phagraphene, and Y-graphene, with capacities that range between 372 to 1489 mA h g À1 . 75 These allotropes have a greater success with Na + ion batteries, with Y-graphene and pentagraphene possessing capacities of 1489 to 1275 mA h g À1 .…”

Engineering strategies and active site identification of MXene-based catalysts for electrochemical conversion reactions

“…19–27 Amongst all the promising catalysts, two-dimensional (2D) materials have drawn intensive attention due to their unique chemical, electrochemical, and physical properties, thus often showing improved properties and performance compared to bulky competitors. 28,29 2D materials are defined as single-layer or multi-layer materials, which mostly consist of one or several layers of bonded atoms. 2D materials such as graphene, phosphorene, transition metal dichalcogenides, metal oxides, layered double hydroxides and metal–organic frameworks have been used for various electrochemical conversion reactions and proven to improve electrochemical performance.…”

Assembly of highly efficient overall CO2 + H2O electrolysis cell with the matchup of CO2 reduction and water oxidation catalyst

“…[1][2][3] To solve these problems, it is especially urgent and important to convert CO 2 to value-added fuels or chemicals via different CO 2 fixation technologies. [4][5][6] Using photosynthesis as an example, 7,8 it has been proposed to engage in artificial photosynthesis by using a combination electrochemical CO 2 reduction and water splitting coupled electrocatalytic system. In a typical overall coupled electrocatalytic reaction of CO 2 + H 2 O, the anode participates in the half reaction of water splitting into the oxygen evolution reaction (OER), and at the cathode, the carbon dioxide reduction reaction (CO 2 RR) occurs to produce fuels such as CO, CH 3 OH, HCOOH, CH 4 , and other high energy/density chemical fuels (CFs), [9][10][11][12] which can be expressed as an overall reaction of CO 2 + H 2 O → CF + O 2 .…”