Concurrently Gathering Catalyst And Reactant On The Surface Of β-cyclodextrin-decorated CdS Nanocrystals Via Host-guest Interactions For Promoting CO₂ Photoreduction

The greenhouse effect caused by excessive carbon dioxide emissions is the main problem affecting the sustainable development of human economy and society.With the increasing impact of greenhouse gases on global climate and environment,more and more attention has been paid to reduce the emission of carbon dioxide.Incorporating CO₂ reduction and organics oxidation into a photocatalytic system while achieving high selectivity is a challenging task,especially in acqueous system.Here,we exploit the host-guest interactions in constructing a photocatalytic supramolecular assembly,in which the water-solubleβ-cyclodextrin（β-CD）decorated Cd S nanocrystals（Cd S-CD）and cobalt meso-tetraphenylporphyrin（Co TPP）are employed as the light absorber and catalyst,respectively.The noncovalent host-guest interactions between theβ-CD modules and Co TPP/furfuryl alcohol have been demonstrated by control experiments with ¹H NMR titration,UV-vis absorption titration,TEM images and transient spectroscopy.The host-guest interactions can facilitate the bidirectional charge transfer processes,one for CO₂-to-HCOOH conversion with a high selectivity of 96.5%and a remarkable yield of about 1609.9μmol g^-1 h^-1,and the other one for furfuryl alcohol oxidation to furfural with a yield of 1567.0μmol g^-1 h^-1 and nearly 100%selectivity,respectively.The double application of host-guest interactions in an integrated photocatalytic system provides an effective strategy for constructing cost-efficient artificial photosynthetic systems.