Powder-precursor integrated 3D-printed TiO2 photocatalyst and adsorption-degradation synergy effect

Abstract

The practicability of nano-powder photocatalyst is limited by the difficulty of its recovery. 3D monolithic TiO2 photocatalyst (MTP) was printed by direct ink writing (DIW) using TiO2 nanoparticles as solutes of tetrabutyl titanate precursor to configure printing slurry to achieve integrated regulation of microscopic and macroscopic pore structure. The SEM verified that the surfaces of skeleton-TiO2 particles were uniformly covered by the TiO2 nanoparticles derived from calcining gel. And a highly connected hierarchical pore structure was formed by the skeleton-TiO2 particles and the designed 3D printing macroscopic pores, which laid the foundation for rapid capture and efficient in situ degradation of antibiotics. The nano TiO2 powders prepared by calcined gel have narrow band gap width, which is easier to generate electrons and holes and have low recombination rate. Therefore, the core-shell structure constructed by nanoparticles derived from gel and commercial TiO2 can effectively optimize the photocatalytic performance of MTP. The removal of tetracycline hydrochloride (TCCH) in water by MTP was used to verify the application effect of macro structure in practice, and the synergistic effect of adsorption and degradation kinetics was summarized. The dynamic adsorption effect of MTP reached 97.44 % at pH 7 for 5 h. Under simulated sunlight, MTP exhibited a synergistic adsorption-degradation effect, reaching equilibrium at 210 min. The cycle test shows that the removal rate of TCCH by MTP remains 91 % after 4 cycles. This strategy provides a good reference for the assembly of nanosemiconductor materials into environmentally friendly 3D structured systems.