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Download filePhase-Selective Disordered Anatase/Ordered Rutile Interface System for Visible-Light-Driven, Metal-Free CO2 Reduction
journal contribution
posted on 2019-09-23, 12:06 authored by Hee Min Hwang, Simgeon Oh, Jae-Hyun Shim, Young-Min Kim, Ansoon Kim, Doyoung Kim, Joosung Kim, Sora Bak, Yunhee Cho, Viet Q. Bui, Thi Anh Le, Hyoyoung LeeVisible-light-driven
photocatalytic CO2 reduction using TiO2 that
can absorb light of all wavelengths has been sought for over half
a century. Herein, we report a phase-selective disordered anatase/ordered
rutile interface system for visible-light-driven, metal-free CO2 reduction using a narrow band structure, whose conduction
band position matches well with the reduction potential of CO2 to CH4 and CO. A mixed disordered anatase/ordered
rutile (Ad/Ro) TiO2 was prepared
from anatase and rutile phase-mixed P25 TiO2 at room temperature
and under an ambient atmosphere in sodium alkyl amine solutions. The
Ad/Ro TiO2 showed a narrow band
structure due to multi-internal energy band gaps of Ti3+ defect sites in the disordered anatase phase, leading to high visible
light absorption and simultaneously providing fast charge separation
through the crystalline rutile phase, which was faster than that of
pristine P25 TiO2. The band gap of Ad/Ro TiO2 is 2.62 eV with a conduction band of −0.27
eV, which matches well with the reduction potential of −0.24
VNHE of CO2/CH4, leading to effective
electron transfer to CO2. As a result, the Ad/Ro TiO2 provided the highest CH4 production (3.983 μmol/(g h)), which is higher than that of
even metal (W, Ru, Ag, and Pt)-doped P25, for CO2 reduction
under visible light.