Boosting C–C coupling to multicarbon products via high-pressure CO electroreduction

Electrochemical CO reduction reaction(CORR) provides a promising approach for producing valuable multicarbon products(C_(2+)), while the low solubility of CO in aqueous solution and high energy barrier of C–C coupling as well as the competing hydrogen evolution reaction(HER) largely limit the efficiency for C_(2+)production in CORR. Here we report an overturn on the Faradaic efficiency of CORR from being HER-dominant to C_(2+)formation-dominant over a wide potential window, accompanied by a significant activity enhancement over a Moss-like Cu catalyst via pressuring CO. With the CO pressure rising from 1 to 40 atm, the C_(2+)Faradaic efficiency and partial current density remarkably increase from 22.8%and 18.9 mA cm^(-2)to 89.7% and 116.7 mA cm^(-2), respectively. Experimental and theoretical investigations reveal that high pressure-induced high CO coverage on metallic Cu surface weakens the Cu–C bond via reducing electron transfer from Cu to adsorbed CO and restrains hydrogen adsorption, which significantly facilitates the C–C coupling while suppressing HER on the predominant Cu(111) surface, thereby boosting the CO electroreduction to C_(2+)activity.

Rational Manipulation of Intermediates on Copper for CO_(2)Electroreduction Toward Multicarbon Products

Excess greenhouse gas emissions,primarily carbon dioxide(CO_(2)),have caused major environmental concerns worldwide.The electroreduction of CO_(2)into valuable chemicals using renewable energy is an ecofriendly approach to achieve carbon neutrality.In this regard,copper(Cu)has attracted considerable attention as the only known metallic catalyst available for converting CO_(2)to high-value multicarbon(C_(2+))products.The production of C_(2+)involves complicated C-C coupling steps and thus imposes high demands on intermediate regulation.In this review,we discuss multiple strategies for modulating intermediates to facilitate C_(2+)formation on Cu-based catalysts.Furthermore,several sophisticated in situ characterization techniques are outlined for elucidating the mechanism of C-C coupling.Lastly,the challenges and future directions of CO_(2)electroreduction to C_(2+)are envisioned.

Synergetic effects of gold-doped copper nanowires with low Au content for enhanced electrocatalytic CO_(2)reduction to multicarbon products

As efficient catalysts of electrochemical CO_(2)reduction reaction(CO_(2)RR)towards multicarbon(C_(2+))products,Cu-based catalysts have faced the challenges of increasing the reactive activity and selectivity.Herein,we decorated the surface of Cu nanowires(Cu NWs)with a small amount of Au nanoparticles(Au NPs)by the homo-nucleation method.When the Au to Cu mass ratio is as little as 0.7 to 99.3,the gold-doped copper nanowires(Cu-Au NWs)could effectively improve the selectivity and activity of CO_(2)RR to C_(2+)resultants,with the Faradaic efficiency(FE)from 39.7%(Cu NWs)to 65.3%,the partial current density from 7.0(Cu NWs)to 12.1 mA/cm^(2) under−1.25 V vs.reversible hydrogen electrode(RHE).The enhanced electrocatalytic performance could be attributed to the following three synergetic factors.The addition of Au nanoparticles caused a rougher surface of the catalyst,which allowed for more active sites exposed.Besides,Au sites generated*CO intermediates spilling over into Cu sites with the calculated efficiency of 87.2%,which are necessary for multicarbon production.Meanwhile,the interphase electron transferred from Cu to Au induced the electron-deficient Cu,which favored the adsorption of*CO to further generate multicarbon productions.Our results uncovered the morphology,tandem,electronic effect between Cu NWs and Au NPs facilitated the activity and selectivity of CO_(2)RR to multicarbons.

Tandem engineering for CO_(2)electrolysis toward multicarbon products

Electrocatalysis of CO_(2)toward multicarbon(C_(2+))products have multifaceted applications in the energy and chemical industries,offers an attractive route to mitigate carbon emissions and abate the depletion of fossil fuels.However,the productivity of CO_(2)-to-C_(2+)products suffers from a low selectivity and reaction rate owing to the difficulty in C-C coupling and the multiple electronproton transfer steps.Recently,numerous tandem catalysts have been developed to improve the selectivity and formation rate of CO_(2)-to-C_(2+)products via coupled multiple reaction steps,exhibiting high industrial practicability.This review summarized recent progresses in the formation of C_(2+)products from CO_(2)electrolysis on tandem catalysts.In this review,we highlight the cooperative regulation strategy of tandem catalysts formed by introducing different types of new components and reveal the relationships between*CO intermediate mass transport and the selectivity of C_(2+)products.Moreover,theoretical insight into the tandem catalytic mechanisms underlying the enhanced C_(2+)selectivity is also provided.Finally,the remaining challenges and opportunities for the electrocatalytic CO_(2)toward C_(2+)products are discussed.

Dynamic structure change of Cu nanoparticles on carbon supports for CO_(2) electro-reduction toward multicarbon products

Cu nanoparticles with different sizes,morphology,and surface structures exhibit distinct activity and selectivity toward CO_(2) reduction reaction,while the reactive sites and reaction mechanisms are very controversial in experiments.In this study,we demonstrate the dynamic structure change of Cu clusters on graphite-like carbon supports plays an important role in the multicarbon production by combining static calculations and ab-initio molecular dynamic simulations.The mobility of Cu clusters on graphite is attributed to the near-degenerate energies of various adsorption configurations,as the interaction between Cu atoms and surface C atoms is weaker than that of Cu-Cu bonds in the tight cluster form.Such structure change of Cu clusters leads to step-like irregular surface structures and appropriate interparticle distances,increasing the selectivity of multicarbon products by reducing the energy barriers of C-C coupling effectively.In contrast,the large ratio of edge and corner sites on Cu clusters is responsible for the increased catalytic activity and selectivity for CO and H_(2) compared with Cu(100)surface,instead of hydrocarbon products like methane and ethylene.The detailed study reveals that the dynamic structure change of the catalysts results in roughened surface morphologies during catalytic reactions and plays an essential role in the selectivity of CO_(2) electro-reduction,which should be paid more attention for studies on the reaction mechanisms.

CO_(2)-assisted formation of grain boundaries for efficient CO–CO coupling on a derived Cu catalyst

The electrochemical CO_(2)reduction reaction(CO_(2)RR)on Cu catalyst holds great promise for converting CO_(2)into valuable multicarbon(C_(2+))compounds,but still suffers poor selectivity due to the sluggish kinetics of forming carbon–carbon(C–C)bonds.Here we reported a perovskite oxide-derived Cu catalyst with abundant grain boundaries for efficient C–C coupling.These grain boundaries are readily created from the structural reconstruction induced by CO_(2)-assisted La leaching.Using this defective catalyst,we achieved a maximum C_(2+)Faradaic efficiency of 80.3%with partial current density over 400 mA cm−2 in neutral electrolyte in a flow-cell electrolyzer.By combining the structural and spectroscopic investigations,we uncovered that the in-situ generated defective sites trapped by grain boundaries enable favorable CO adsorption and thus promote C–C coupling kinetics for C_(2+)products formation.This work showcases the great potential of perovskite materials for efficient production of valuable multicarbon compounds via CO_(2)RR electrochemistry.

Graphdiyene enables ultrafine Cu nanoparticles to selectively reduce CO_(2) to C_(2+)products

Reducing the size of heterogeneous nanocatalysts is generally conducive to improving their atomic utilization and activities in various catalytic reactions.However,this strategy has proven less effective for Cu-based electrocatalysts for the reduction of CO_(2) to multicarbon(O2+)products,owing to the overly strong binding of intermediates on small-sized(<15 nm)Cu nanoparticles(NPs).Herein,by incorporating pyreny-graphdiyne(Pyr-GDY),we successfully endowed ultrafine(〜2 nm)Cu NPs with a significantly elevated selectivity for CO_(2)-to-C_(2+)conversion.The Pyr-GDY can not only help to relax the overly strong binding between adsorbed H*and CO*intermediates on Cu NPs by tailoring the d-band center of the catalyst,but also stabilize the ultrafine Cu NPs through the high affinity between alkyne moieties and Cu NPs.The resulting Pyr-GDY-Cu composite catalyst gave a Faradic efficiency(FE)for C2+products up to 74%,significantly higher than those of support-free Cu NPs(C2+FE.〜2%),carbon nanotube-supported Cu NPs(CNT-Cu,C_(2+)FE,〜18%),graphene oxide-supported Cu NPs(GO-Cu,C_(2+)FE,〜8%),and other reported ultrafine Cu NPs.Our results demonstrate the critical influence of graphdiyne on the selectivity of Cu-catalyzed CO_(2) electroreduction,and showcase the prospect for ultrafine Cu NPs catalysts to convert CO_(2) into value-added C_(2+)products.

多碳生成工厂:用于提高CO_(2)电催化生产率的CuO/Ni单原子串联催化剂

电化学CO_(2)还原反应(CO_(2)RR)的串联电催化策略是将CO_(2)到C_(2+)的多个步骤解耦为单独催化的CO_(2)到CO和CO到C_(2+)的两个步骤,以提高法拉第效率(FE).然而,由于CO从生成位点到反应位点的传质限制,这种策略对于C_(2+)的高速率生产仍然是挑战.本文设计了CuO/Ni单原子(SAs)串联催化剂,使得用于独立催化CO_(2)-到-CO和CO-到-C_(2+)的Ni和Cu的催化位点紧密相邻,能够原位产生和快速消耗CO.CuO/Ni SAs串联催化剂实现了高C_(2+)的部分电流密度(1220.8 mA/cm^(2)),同时仍然保持了优异的C_(2+)FE(81.4%).