In the present study, we investigate the surface acid-base properties of anatase TiO2 nanomaterials with dominant {101} and {001} facets via methanol titrations. Two anatase nanoparticles, TiO2(101) and TiO2(001), with well-defined morphology are prepared. TiO2(101) is predominantly enclosed by the {101} facets (> 90%), and TiO2(001) contains ~46% {001} facets and ~54% {101} facets. Upon adsorption of methanol 423 K, DRIFTS measurements show that both molecular and dissociative adsorption occurs on TiO2(101), while dissociative adsorption dominates on TiO2(001). During methanol TPD, TiO2(001) mainly generates acid-base product dimethyl ether and thermal cracking products CO and H2, as anticipated. In contrast, substantial amounts of formaldehyde and methane also desorb from TiO2(101), suggesting strong participation of surface defects (e.g., oxygen vacancies).
Published: August 24, 2023
Citation
Wu Y., F. Gao, H. Wang, L. Kovarik, B.J. Sudduth, and Y. Wang. 2021.Probing acid-base properties of anatase TiO2 nanoparticles with dominant {001} and {101} facets using methanol chemisorption and surface reactions.Journal of Physical Chemistry C 125, no. 7:3988-4000.PNNL-SA-158674.doi:10.1021/acs.jpcc.0c11107