Size‐Dependent Activity and Selectivity of Atomic‐Level Copper Nanoclusters during CO/CO₂ Electroreduction

Abstract

As af avorite descriptor,t he size effect of Cu-based catalysts has been regularly utilized for activity and selectivity regulation toward CO 2 /CO electroreduction reactions (CO 2 / CORR). However,l ittle progress has been made in regulating the sizeofCunanoclusters at the atomic level. Herein, the sizegradient Cu catalysts from single atoms (SAs) to subnanometric clusters (SCs,0.5-1 nm) to nanoclusters (NCs,1-1.5 nm) on graphdiyne matrix are readily prepared via an acetylenicbond-directed site-trapping approach.E lectrocatalytic measurements showasignificant sizeeffect in both the activity and selectivity towardC O 2 /CORR. Increasing the sizeo fC u nanoclusters will improve catalytic activity and selectivity towardC 2+ productions in CORR. Ahigh C 2+ conversion rate of 312 mA cm À2 with the Faradaic efficiency of 91.2 %a re achieved at À1.0 Vv ersus reversible hydrogen electrode (RHE) over Cu NCs.T he activity/selectivity-sizer elations provideaclear understanding of mechanisms in the CO 2 / CORR at the atomic level.

Recent Advances in Catalyst Structure and Composition Engineering Strategies for Regulating CO2 Electrochemical Reduction

“…The surface facet composition is also a function of particle size. [69] Usually, CO and H 2 were dominant products on ultrafine Cu nanoparticles (<2 nm) [69,70] due to the high population of low-coordinated surface sites (CN < 8) and their strong adsorption for *H and *CO. Recently, ≈1 nm Cu clusters confined in defective carbon enabled a maximum methane FE of 81.7%, which was ascribed to the combined fine size and strong metal-support interaction effects that optimizing the *H and *CO adsorption.…”

Study on the Structure‐Activity Relationship Between Single‐Atom, Cluster and Nanoparticle Catalysts in a Hierarchical Structure for the Oxygen Reduction Reaction

“…[6][7][8][9][10] Literature reports confirmed in primary structures SACs exhibit superior catalytic efficiency when compared with their cluster and nanoparticles (NPs) counterparts. [11,12] The better catalytic performance has been reasoned as follows: (1) SACs have the highest metal atom utilization efficiency; [13][14][15] (2) SACs could facilitate generation and conversion of intermediates, resulting in different reactivities; [6,7] (3) SACs could benefit precise tuning of metal-adsorbate interactions and the adsorption strength of O 2 to achieve an optimal energetic profile for the overall process. [16] Compared with a primary structure, a chemically identical hierarchical structure could increase active sites, enhance the accessibility of active sites and electrolytes as well as oxygen molecules, accelerate mass/charge transfer ability and improve the stability, especially in some NPs catalytic research.…”

Size Dependent CO2 Reduction Activity of Ag Nanoparticle Electrocatalysts

“…Size-dependent CO2RR vs. HER is well understood at Au and Cu nanoparticles thanks to agreement between experimental and theoretical investigations, [15][16][17][18] and it is generally agreed that a higher density of undercoordinated corner sites on smaller diameter nanoparticles can increase H2 production and reduce selectivity toward CO. However, there is still a lack of fundamental consensus on how size-dependent CO selectivity and activity evolve for pristine Ag nanoparticles because the ligands, capping agents, and/or stabilizers often used to control nanoparticle size, shape, and crystallographic orientation can block, passivate, or modify specific surface sites.…”

“…Interestingly, it was the Ag edge sites that impacted HER, whereas undercoordinated corner sites are believed to most strongly impact HER from Au and Cu nanoparticles. [15][16][17][18] Finally, we directly validated our computational results by preparing and evaluating the CO2RR performance of a series of pristine Ag nanocatalysts with well-controlled diameters.…”