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Self‐Enhancing H 2 Evolution from TiO 2 Nanostructures under Illumination
Author(s) -
Wierzbicka Ewa,
Zhou Xuemei,
Denisov Nikita,
Yoo JeongEun,
Fehn Dominik,
Liu Ning,
Meyer Karsten,
Schmuki Patrik
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201900192
Subject(s) - electron paramagnetic resonance , anatase , photocatalysis , photochemistry , materials science , spectroscopy , aqueous solution , nanoparticle , nanostructure , resonance (particle physics) , visible spectrum , nanotechnology , chemistry , catalysis , nuclear magnetic resonance , optoelectronics , atomic physics , organic chemistry , physics , quantum mechanics
Abstract Illumination of anatase in an aqueous methanolic solution leads to the formation of Ti 3+ sites that are catalytically active for the generation of dihydrogen (H 2 ). With increasing illumination time, a light‐induced self‐amplification of the photocatalytic H 2 production rate can be observed. The effect is characterized by electron paramagnetic resonance (EPR) spectroscopy, reflectivity, and photoelectrochemical techniques. Combined measurements of H 2 generation rates and in situ EPR spectroscopic observation over the illumination time with AM 1.5G or UV light establish that the activation is accompanied by the formation of Ti 3+ states, which is validated through their characteristic EPR resonance at g =1.93. This self‐activation and amplification behavior can be observed for anatase nanoparticles and nanotubes.