Introducing O vacancies into the lattice of a semiconductor photocatalyst can alter its intrinsic electronic properties and band gap, thus enhancing the visible light absorption, promoting the separation/transfer of photogenerated charge carriers, and resultantly elevating the photocatalytic activity of oxide semiconductors. Moreover, O vacancies can help adsorb and activate CO 2 on photocatalyst surfaces, which, however, are prone to being filled by O atoms during the photoreduction reaction. In this work, Cu was introduced to increase the O vacancy concentration in CeO 2−x and promote the photocatalytic activity of CeO 2−x . The sample Cu/CeO 2−x -0.1 showed the highest photocatalytic activity with a CO yield of 8.25 μmol g −1 under 5 h irradiation, which is ∼26 times that on CeO 2−x . According to the analysis of Raman and X-ray photoelectron spectroscopy (XPS) spectra, it has been evidenced that Cu introduction benefits the chemical stabilization of O vacancies in CeO 2−x during photocatalytic CO 2 reduction, which is responsible for the improved and sustained photocatalytic activity.

P-doped g-C3N4 has been successfully synthesized using hexachlorocyclotriphosphazene, a low cost and environmentally benign compound, as phosphorus source, and guanidiniumhydrochloride as g-C3N4 precursor, via a thermally induced copolymerization route.

A stability-difference-selective bond-breakage strategy for the fabrication of largepore-sized hollow mesoporous organosilica nanoparticles (HMONs) is successfully developed. Moreover, surfacefunctionalized HMONs are successfully constructed to simultaneously deliver P-gp modulator siRNA and anticancer drug doxorubicin to reverse the multidrug resistance of cancer cells.