Millimeter-level nitrogen modified activated carbon spheres assisted Bi4Ti3O12 composites for bifunctional adsorption/photoreduction of CO2

The increase of CO 2 adsorption and separation efficiency of photo-induced carriers are two crucial factors for achieving effective CO 2 reduction into solar fuels. Here, novel millimeter-level nitrogen modified resin-based activated carbon spheres (N-ACSs), as desired support to immobilize and tailor Bi 4 Ti 3 O 12 catalyst (Bi 4 Ti 3 O 12 /N-ACSs) for improving CO 2 photoreduction activities, have been constructed via simple suspension polymerization and impregnation method. The involved TG, FTIR, XRD, XPS, EA, SEM, EDS, N 2 adsorption/desorption, CO 2 adsorption, UV–vis DRS, MS, PC, EIS, PL spectra and in-situ FTIR were characterized. Bi 4 Ti 3 O 12 /N-ACSs displayed the highest photocatalytic CO 2 reduction activity to CO of 142.76 μmol/g under 8 h simulated sunlight irradiation in pure H 2 O phase, approximately 1.45 times and 1.24 times higher than that of pristine Bi 4 Ti 3 O 12 and Bi 4 Ti 3 O 12 /ACSs, respectively. The introduction of N-ACSs played four roles: (i) the increase of CO 2 adsorption, (ii) the red-shift of optical absorption range, (iii) the consummate separation and transfer of photo-induced carriers, (iv) more CO 2 active sites. Finally, the possible mechanism photocatalytic CO 2 reduction for Bi 4 Ti 3 O 12 /N-ACSs was proposed. Our findings should provide noteworthy promising strategy to immobilize powder photocatalyst on the surface of millimeter-level carbon spheres for achieving the high-efficient CO 2 adsorption and photoreduction to CO.