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

Abstract

million (ppm), which is ≈50% higher than that of the pre-industrial level (280 ppm). [1] The consequent climate change (the average temperature increase of 0.8 °C above the pre-industrial level) causes global warming, one of the top environmental concerns. [2] To maintain the sustainable development of the society, the Intergovernmental Panel on Climate Change (IPCC) recently recommended the warming limit to 1.5 °C rather than 2.0 °C to reduce catastrophic climate change issues, requiring the commitment to take action to control global carbon emission. [3] Under the Paris Agreement, many countries endeavor to reduce greenhouse gas emissions gradually by 2030. [4] The carbon capture and storage (CCS) is a feasible strategy to lower the CO 2 emissions substantially. Long-term storage issues related to the leakage of CO 2 and the lack of economic incentives limited its development. [5] The CO 2 reduction reactions (CO 2 RR) that convert CO 2 into other value-added carbon products could provide a well alternative to the utilization of the captured CO 2 , which not only contributes to the mitigation of CO 2 emission but also offers useful products that can serve as fuels such as CO, HCOOH, CH 3 OH, and CH 4. [6] Moreover, the drive power of CO 2 RR could come from renewable energy resources, such as solar, wind, and hydraulic resources, which indicates that in a green concept, CO 2 RR could complete the carbon loop and potentially solve the issues of global warming and energy crisis simultaneously. [7] 1.1. Fundamental Reaction Pathways of CO 2 RR CO 2 RR is not thermodynamically and kinetically favorable. Every reduction pathway demands a certain amount of energy input. Equations (1-13) shows the reaction steps involved in CO 2 RR (in pH = 7 aqueous solution, vs Normal Hydrogen Electrode (NHE)). [8] As illustrated, it requires a significant amount of reorganizational energy between the linear molecule CO 2 and the bent radical anion − CO 2 • (Equation (1)). When coupling with proton in the reaction, the required reaction energy decreases (Equations (2-12)). Aqueous media with H 2 O molecules become ideal for providing proton into the CO 2 RR system. The reduction potential of hydrogen evolution reaction (HER) (Equation (13)) is close to that of CO 2 RR. It makes HER a competitive reaction against CO 2 RR during the reduction CO 2 reduction reaction (CO 2 RR) provides a promising strategy for sustainable carbon fixation by converting CO 2 into value-added fuels and chemicals. In recent years, considerable efforts are focused on the development of transition-metal (TM)-based catalysts for the selectively electrochemical CO 2 reduction reaction (ECO 2 RR). Co-based catalysts emerge as one of the most promising electrocatalysts with high Faradaic efficiency, current density, and low overpotential, exhibiting excellent catalytic performance toward ECO 2 RR for CO and HCOOH productions that are economically viable. The intrinsic contribution of Co and the synergistic effects in Co-hybrid catalysts play essential roles for ...

Atomically Dispersed Ni/Cu Dual Sites for Boosting the CO2 Reduction Reaction

“…Potentiostatic electrolysis was further conducted to evaluate the reduction products in an electrochemical hydrogen pump reactor. , The liquid and gaseous products were examined by off-line 1 H NMR and online GC, respectively. The onset potential (defined as the potential at which CO was first detected by GC , ) of Ni/Cu–N–C is as low as −0.19 V vs RHE. As observed in Figure b, Ni/Cu–N–C reaches a maximum FE CO of 99.2% at −0.79 V vs RHE and over 95% from −0.39 to −1.09 V vs RHE.…”

Atomically Dispersed Fe-Co Bimetallic Catalysts for the Promoted Electroreduction of Carbon Dioxide

“…The electroreduction reaction of CO 2 (ECO 2 RR) contains advantages because of the great potential in future commercialization including renewable energy-generated electricity and easy scale-up. One of the most economic reduction products from ECO 2 RR, carbon monoxide (CO) that is the main component of syngas (gas mixture of CO and H 2 ) attracts considerable attention [2]. CO or syngas produced from ECO 2 RR can be applied as feedstock in established industrial processes (e.g., Fischer − Tropsch synthesis) for the production of various important chemicals, such as long-chain hydrocarbons, methanol, higher alcohols, and fuels [3][4][5].…”

2D/2D Heterostructures: Rational Design for Advanced Batteries and Electrocatalysis

“…The combination of the different 2D materials into 2D/2D heterostructures provides us vast space to design distinct catalysts to meet different requirements to trigger the various sustainable energy storage and green fuel generation reactions, as demonstrated in Table 1. [189][190][191][192] More future work should be conducted to identify the possible permutations and combinations for efficient 2D/2D heterostructure catalysts. Moreover, the mechanism understandings at an atomic or molecular level on the above-mentioned catalytic activity originations within the 2D/2D heterostructures through advanced in situ/operando characterization techniques and theoretical calculation and simulation approaches are urgently needed.…”