Preparation and photocatalytic CO2 reduction performance of silver nanoparticles coated with coal-based carbon dots

Currently, the best approach to solve the increasing CO2 emission and energy shortage problems comes from catalytic CO2 reduction into organic fuels using solar radiation. Using inexpensive coal samples, here we synthesized coal-based luminescent carbon dots (CDs) by H2O2 oxidation method. Coated composite nanoparticle Ag/CDs were then fabricated using a simple silver mirror reaction to attach CDs in situ to Ag surface. The lattice structure of Ag/CDs was characterized, and the performance of photocatalytic CO2 reduction into hydrocarbons was investigated. The surface of the composite contains a large number of oxygen groups and mesoporous interface from accumulation of uniform-sized particles, demonstrating good adsorption capability for CO2. Thanks to the broad absorption spectra extending into the visible range and low recombination rate of photogenerated electron-hole pairs, the composite nanoparticles can be applied in the photocatalytic CO2 reduction. Compared with individual Ag and CDs, Ag/CDs exhibit enhanced photocatalytic activity for CO2 reduction.