Abstract
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 at 423 K, diffuse reflectance infrared Fourier transform spectroscopy measurements show that both molecular and dissociative adsorption occur on TiO2(101), while dissociative adsorption dominates on TiO2(001). During methanol temperature-programmed desorption, TiO2(001) mainly generates the 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).
| Original language | English |
|---|---|
| Pages (from-to) | 3988-4000 |
| Number of pages | 13 |
| Journal | Journal of Physical Chemistry C |
| Volume | 125 |
| Issue number | 7 |
| DOIs | |
| State | Published - Feb 25 2021 |
| Externally published | Yes |
Funding
The authors acknowledge the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences for funding this project. Part of this work was conducted in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for the DOE by Battelle under Contract DE-AC05-76RL01830. The authors are grateful to fruitful discussions with Drs. Roger Rousseau, Zdenek Dohnalek, and Janos Szanyi from PNNL.