Photoreduction of CO2 over the well-crystallized ordered mesoporous TiO2 with the confined space effect

• Published in: Nano energy 2014-10, Vol.9, p.50-60
• Main Authors: Wang, Tao, Meng, Xianguang, Li, Peng, Ouyang, Shuxin, Chang, Kun, Liu, Guigao, Mei, Zongwei, Ye, Jinhua
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Confined space effect; Cross-disciplinary physics: materials science; rheology; Diffusion in nanoscale solids; Diffusion in solids; Exact sciences and technology; Materials science; Methods of nanofabrication; Ordered mesoporous structure; Photoreduction of carbon dioxide; Physics; Self-assembly; Solid surfaces and solid-solid interfaces; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Transport properties of condensed matter (nonelectronic); Well-crystallized titanium dioxide
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2014.06.027

Ordered mesoporous titanium dioxide with crystalline wall was successfully synthesized by combining evaporation induced self-assembly process with two-step calcination processes. The ordered mesoporous titanium dioxide not only shows a higher production efficiency of CH4, which is 71 times and 53 times higher than that of commercial titanium dioxide (P25) and disordered mesoporous titanium dioxide, respectively, but also exhibits a better stability for CO2 photoreduction. The remarkable performance of the ordered mesoporous titanium dioxide for CO2 photoreduction probably benefits from the confined space effect of ordered mesoporous structure because (1) the active sites exist not only on the surface of the particles, but also exist in the pores; (2) gas molecules collide with the pore walls more frequently in the case of Knudsen diffusion; (3) the highly ordered mesoporous structure develops a high-efficient CO2 adsorption ability, smooth flow of gas molecules and improved separation and transport of electron–hole. Ordered mesoporous TiO2 not only shows a higher production efficienty of CH4, which is 71 times and 53 times higher than that of P25 and disordered mesoporous TiO2, but also exhibits a better photocatalytic stability. And we proved that the 13CH4 was generated by the reduction of 13CO2, and the CD4 was generated by the reforming of CO2 and D2O. [Display omitted] •The confined space effect of ordered mesoporous structure for CO2 photoreduction.•A simple and reproducible route to synthesize well-crystallized ordered mesoporous TiO2.•Higher production efficiency and better stability for CO2 photoreduction.•Confirmed that the H and C atoms of CH4 are from CO2 and H2O by using the 13CO2 and D2O detection technique.