Facile decoration of carbon fibers with Ag nanoparticles for adsorption and photocatalytic reduction of CO2

Carbon fibers (CFs) decorated with Ag nanoparticles (Ag NPs), hereafter denoted as Ag NPs/CFs, have been successfully synthesized via a simple solution dipping combined with an ultrasonic treatment. CFs are decorated by spherical Ag NPs with 20–50 nm diameters mainly consisted of the Ag nanocrystals, which is reduced from Ag+ by both CFs and polyviylpyrrolidone (PVP). The aggregation of Ag NPs on the surface of CFs via Ostwald ripening and from the solution are the primarily responsible for the formation of spherical Ag NPs. The as-prepared Ag NPs/CFs Exhibits 4-time higher of photocatalytic activity than the pure Ag NPs, meanwhile enhancing the selectivity to convert CO2 into CH3OH. A possible visible light photocatalytic mechanism for the better performance and selectivity of Ag NPs/CFs is discussed. The significant enhancement of the CO2 photocatalytic reduction is primarily attributed to the increase of CO2 adsorption and the efficient electron transfer to CO2 as well as the active site splitting of CO2 reduction and H2O decomposition.