Boosting the Productivity of Electrochemical CO₂Reduction to Multi‐Carbon Products by Enhancing CO₂Diffusion through a Porous Organic Cage

Abstract

Electroreduction of CO 2 into valuable fuels and feedstocks offers a promising way for CO 2 utilization. However, the commercialization is limited by the low productivity. Here, we report a strategy to enhance the productivity of CO 2 electroreduction by improving diffusion of CO 2 to the surface of catalysts using porous organic cages (POCs) as an additive. It was noted that the Faradaic efficiency (FE) of C2 + products could reach 76.1 % with a current density of 1.7 A cm À 2 when Cu-nanorod(nr)/CC3 (one of the POCs) was used, which were much higher than that using Cu-nr. Detailed studies demonstrated that the hydrophobic pores of CC3 can adsorb a large amount of CO 2 for the reaction, and the diffusion of CO 2 in the CC3 to the nanocatalyst surface is easier than that in the liquid electrolyte. Thus, more CO 2 molecules make contact with the nanocatalysts in the presence of CC3, enhancing CO 2 reduction and inhibiting generation of H 2 .

A Porous π–π Stacking Framework with Dicopper(I) Sites and Adjacent Proton Relays for Electroreduction of CO2 to C2+ Products

“…Based on the obtained FE and current density, the reaction rate and turnover frequency for C 2+ products were calculated as 5639 μmol m –2 s –1 and 0.16 s –1 [ i.e., ethylene (0.056 s –1 ), ethanol (0.058 s –1 ) and acetate (0.044 s –1 )], respectively. Notably, CuBtz exhibits the highest reaction rate for yielding C 2+ products among almost all of the ECR catalysts (Table S2) except three metallic copper-based materials Cu/Fe–N–C , Cu-nr/CC3 , and F–Cu with reaction rates of ∼9380, ∼10 030, and 11 147 μmol m –2 s –1 , respectively. ,, By comprehensively considering the reaction rate, current density, and FE­(C 2+ ) (Figure e), CuBtz exhibits the highest performance for yielding C 2+ products among almost all of the coordination compounds.…”

“…Notably, CuBtz exhibits the highest reaction rate for yielding C 2+ products among almost all of the ECR catalysts (Table S2) except three metallic copper-based materials Cu/Fe−N−C, Cu-nr/CC3, and F−Cu with reaction rates of ∼9380, ∼10 030, and 11 147 μmol m −2 s −1 , respectively. 5,43,44 By comprehensively considering the reaction rate, current density, and FE(C 2+ ) (Figure 2e), CuBtz exhibits the highest performance for yielding C 2+ products among almost all of the coordination compounds.…”

Selective CO2 Reduction to Ethylene Using Imidazolium-Functionalized Copper

“…The reduction of CO 2 (CO 2 RR) into value-added chemicals using renewable sources provides a sustainable way for energy conversion. , For the electrochemical approach, Cu-based catalysts have drawn great attention due to their activities of converting CO 2 into multicarbon products . A major challenge is improving the selectivity of products with high industrial value such as ethylene and alcohols, from the 16 products observed during catalysis. , Recent studies on catalyst development have shown high selectivity for C ≥2 products. − However, the selectivity of a particular multicarbon product on less-expensive polycrystalline Cu is relatively low. Thus, developing methods, especially the ones that are able to shift the reaction pathways between ethylene and ethanol, would be of great value for achieving highly selective CO 2 reduction systems.…”

In Situ Reconstruction of Cu–N Coordinated MOFs to Generate Dispersive Cu/Cu2O Nanoclusters for Selective Electroreduction of CO2to C2H4

“…Electrochemical CO 2 reduction provides a promising strategy to convert CO 2 into high-value-added fuels and industrial feedstocks. , Up to now, the known products of CO 2 electroreduction include CO, HCOOH, CH 4 , C 2 H 4 , C 2 H 5 OH, etc. − Compared with C 1 products, C 2+ products have higher energy density and higher market value. − It is well known that great breakthrough has been made in the design and research of electroreduction catalysts to obtain hydrocarbons, but the reaction is still limited by the poor C 2+ selectivity and low activity. − Among the developed and used electrocatalysts, Cu-based materials are the most promising for the synthesis of multi-carbon products in the CO 2 RR because of the moderate binding energy of the *CO intermediate, which provides favorable conditions for the C–C coupling step. − However, the low selectivity and activity of C 2+ products and low current densities limit the wide application of Cu-based catalysts, which are still worthy of further study.…”