It is essential to develop a cheap, recyclable, and efficient photocatalyst to help degrade pollutants contaminating the environment. Herein, mesoporous molecular sieve titanium phosphate (MMS-TiP) was used as an efficient nano-photocatalyst to degrade 2, 4-dichlorophenol (2, 4-DCP) and to oxidize CO. The catalyst was successfully synthesized by a simple and convenient hydrothermal method in the presence of a tri-block copolymer surfactant. Exceptional photoactivity of the optimized MMS-TiP mainly depends on its porous structure, with a large surface area by means of O₂ temperature-programmed desorption curves and fluorescence spectra related to the amounts of produced hydroxyl radical. Interestingly, the photocatalytic activity of the prepared MMS-TiP could be greatly improved by coupling with nanocrystalline SnO₂. This is likely due to the increase in the lifetime and separation of photogenerated charges by transferring electrons to SnO₂ and was observed by steady-state surface photovoltage spectra and time-resolved surface photovoltage responses. The SnO₂-coupled MMS-TiP exhibits better photocatalytic performance for 2, 4-DCP degradation and better self-settlement than those of the commercial catalyst P25 TiO₂. Moreover, it was confirmed by radical-trapping experiments that ·O₂–is the main activated species for the photocatalytic degradation of 2, 4-DCP, and is photogenerated by electron transfer from MMS-TiP to SnO₂. Furthermore, the main intermediates in the degradation of 2, 4-DCP, like parachlorophenol superoxide and 1, 2-benzenediol superoxide radicals, were detected, and a possible decomposition pathway related to ·O₂–attack is proposed. These experimental results provide new strategies for developing a recyclable molecular sievebased nano-photocatalyst with high photocatalytic activity for environmental remediation.

To develop efficient visible-light photocatalysis on α-Fe₂O₃, it is highly desirable to promote visible-light-excited high-energy-level electron transfer to a proper energy platform thermodynamically. Herein, based on the transient-state surface photovoltage responses and the atmosphere-controlled steady-state surface photovoltage spectra, it is demonstrated that the lifetime and separation of photogenerated charges of nanosized α-Fe₂O₃ are increased after coupling a proper amount of nanocrystalline SnO₂. This naturally leads to greatly improved photocatalytic activities for CO₂ reduction and acetaldehyde degradation. It is suggested that the enhanced charge separation results from the electron transfer from α-Fe₂O₃ to SnO₂, which acts as a proper energy platform. Based on the photocurrent action spectra, it is confirmed that the coupled SnO₂ exhibits longer visible-light threshold wavelength (~590 nm) compared with the coupled TiO₂ (~550 nm), indicating that the energy platform introduced by SnO₂ would accept more photogenerated electrons from α-Fe₂O₃. Moreover, electrochemical reduction experiments proved that the coupled SnO₂ possesses better catalytic ability for reducing CO₂ and O₂. These are well responsible for the much efficient photocatalysis on SnO₂-coupled α-Fe₂O₃.