Dual structure cobalt sites on surface hydroxyl and oxygen vacancy of BiOCl for cooperative CO2 reduction and tetracycline oxidation

Abstract

Metal ion cocatalysts have huge prospect for photocatalytic CO2 reduction coupled with organic decomposition because of their cost effectiveness and abundant active sites. Herein, we exploit a defect−group oriented tactic to induce dual−structured Co sites on BiOCl with rich surface hydroxyls (OHs) and oxygen vacancies (OVs) (labeled as BiO1−xCl−OH), in which the surface OHs and OVs acted as anchoring points to anchor Co2+ ions. Density functional theory calculations manifested that surface OHs anchored Co2+ ions via hydrogen bonding to produce tight OH−Co sites, meanwhile, surface OVs with unsaturated metal sites and unpaired electrons captured Co2+ ions through chemical bonding to form close−knit OV−Co site. The as−generated OV−Co and OH−Co site served as reductive and oxidative cocatalyst for CO2 reduction and tetracycline oxidation, respectively, thereby achieving high−efficiency redox activity. This work provided a novel strategy to devise progressive dual functional metal ions cocatalysts for high−efficiency CO2 reduction and organic pollutants oxidation.