posted on 2021-12-27, 14:39authored byXiaoyuan Ye, Changgeng Wei, Sikang Xue, Wandong Xing, Xiaocong Liang, Hongbo Nie, Min Shen, Yong Du, Jinshui Zhang, Xinchen Wang, Wei Lin, Zhiyang Yu
Tunable
crystalline defects endow WO3–x catalysts with extended functionalities for a broad range
of photo- and electric-related applications. However, direct visualization
of the defect structures and their evolution mechanism is lacking.
Herein, aberration-corrected and in situ transmission
electron microscopy was complemented by theoretical calculations to
investigate the effect of temperature on the defect evolution behavior
during hydrogenation treatment. Low processing temperature (100–300
°C) leads to the occurrence of randomly distributed oxygen vacancies
within WO3–x nanosheets. At higher
temperatures, oxygen vacancies become highly mobile and aggregate
into stacking faults. Planar defects are prone to nucleate at the
surface and develop in a zigzag form at 400 °C, while treating
at 500 °C promotes the growth of {200}-type stacking faults.
Our work clearly establishes that the atomic configuration of the
defects in WO3–x samples could
be manipulated by regulating the hydrogenation temperature. This study
not only expands our understanding of the structure–function
relationships of sub-stoichiometric tungsten oxides but also unlocks
their full potential as advanced catalysts by tuning stoichiometry
in a controlled manner.