Graphdiyene Enables Ultrafine Cu Nanoparticles To Selectively Reduce CO₂ To C₂₊ Products

The utilization of CO₂ resources can not only alleviate human dependence on traditional fossil resources,but also effectively reduce the concentration of CO₂ in the atmosphere.Among the many CO₂ conversion and utilization technologies,electrochemical reduction of CO₂ has aroused the research interest of the majority of scientific researchers because of its simple reaction conditions,high conversion efficiency,and ease of large-scale industrial production.Previous studies have shown that Cu is the only metal that can produce multicarbon products(C₂₊)by electrocatalytic CO₂ reduction,with a fairly high Faraday efficiency.In order to improve the CO₂RR performance of Cu-based catalysts in the production of C₂₊products,nano-modification of bulk copper catalysts through various methods has been extensively studied.Studies have shown that further nano-modification can effectively improve the performance of bulk copper catalysts to produce C₂₊products,because bulk copper with a flat surface is more likely to produce CH₄ and also produce a large amount of H₂ at the same time even at the best potential.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 reduction CO₂to C₂₊products,owing to the overly strong binding of intermediates on small-sized(<15 nm)Cu nanoparticles(NPs).Herein,by incorporating pyrenyl-graphdiyne(Pyr-GDY),we successfully endowed ultrafine(?2 nm)Cu NPs with a significantly elevated selectivity for CO₂-to-C₂₊conversion.The Pyr-GDY not only can 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 can stabilize the ultrafine Cu NPs through the high affinity between alkyne moieties and Cu NPs.The resulting Pyr-GDY-Cu composite catalyst gave a Faradaic 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,C₂₊FE,?18%),graphene oxide-supported Cu NPs(GO-Cu,C₂₊FE,?8%),and other reported ultrafine Cu NPs.Our results demonstrate the critical influence of graphdiyne on the selectivity of Cu-catalyzed CO₂ electroreduction,and showcase the prospect for ultrafine Cu NPs catalysts to convert CO₂ into value-added C₂₊products.