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Adjustment and Matching of Energy Band of TiO2-Based Photocatalysts by Metal Ions (Pd, Cu, Mn) for Photoreduction of CO2 into CH4

Yan, Yabin, Yu, Yanlong, Huang, Shaolong, Yang, Yajun, Yang, Xiaodan, Yin, Shougen, Cao, Yaan
The Journal of Physical Chemistry C 2017 v.121 no.2 pp. 1089-1098
Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, absorption, carbon dioxide, copper, energy, energy-dispersive X-ray analysis, manganese, metal ions, methane, palladium, photocatalysis, photocatalysts, photoluminescence, redox potential, sol-gel processing, titanium dioxide, ultraviolet-visible spectroscopy
A series of the metal ions (Pd, Cu, and Mn) modified TiO₂ photocatalysts are synthesized via simple sol–gel method. Characterized by X-ray diffraction, Raman, UV–vis absorption spectra, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, time-resolved photoluminescence (PL) decay curves, and PL, it was revealed these introduced metal ions existed as O–Me–O species (Me: Pd, Cu, and Mn) on the surface of TiO₂. The corresponding theory calculation is used to investigate the electronic density of states and band structure of the metal ions (Pd, Cu, and Mn) modified TiO₂. The modified TiO₂ photocatalysts exhibit an improved photocatalytic performance on reduction of CO₂ and H₂O into methane (CH₄), attributed to the contribution of surface species by enhancing the visible absorption efficiently, separating charge carriers, and matching of the redox potential on the photoreduction of CO₂ into CH₄. This article could provide a wider understanding about the adjustment and matching of the energy level for the synthesis and design of functional materials with excellent photocatalytic performance.