Journal of Physical Chemistry C
Journal of Physical Chemistry C
5 years ago

Computational Investigation on Hydrodeoxygenation (HDO) of Acetone to Propylene on α-MoO3 (010) Surface

Computational Investigation on Hydrodeoxygenation (HDO) of Acetone to Propylene on α-MoO3 (010) Surface
Beat Buesser, William H. Green, Yuriy Román-Leshkov, Manish Shetty
Density functional theory (DFT) calculations were performed on the multistep hydrodeoxygenation (HDO) of acetone (CH3COCH3) to propylene (CH3CHCH2) on a molybdenum oxide (α-MoO3) catalyst following an oxygen vacancy-driven pathway. First, a perfect O-terminated α-MoO3 (010) surface based on a 4 × 2 × 4 supercell is reduced by molecular hydrogen (H2) to generate a terminal oxygen (Ot) defect site. This process occurs via a dissociative chemisorption of H2 on adjacent surface oxygen atoms, followed by an H transfer to form a water molecule (H2O). Next, adsorption of CH3COCH3 on the oxygen-deficient Mo site forms an O–Mo bond and then the chemisorbed CH3COCH3 forms CH3COCH2 by transfer of an H atom to an adjacent Ot site. The surface bound hydroxyl (OH) then transfers the H atom to the immobilized O atom to form surface-bound enol, CH3CHOCH2. The next step releases CH3CHCH2 into the gas phase, while simultaneously oxidizes the surface back to a perfect O-terminated α-MoO3 (010) surface. The adsorption of H2, and the formation of a terminal oxygen (Ot) vacancy, moves the conduction band minimum (CBM) from 1.2 eV to 0 and 0.3 eV, respectively. Climbing image-nudged elastic band (CI-NEB) calculations using a Perdew–Burke–Ernzerhof (PBE) functional in combination with double-ζ valence (DZV) basis sets indicate that the dissociative adsorption of H2 is the rate-limiting step for the catalytic cycle with a barrier of 1.70 eV. Furthermore, the lower barrier for surface-mediated H transfer from primary-to-secondary carbon atom (0.63 eV) compared to that of a concerted direct H transfer to the secondary C atom with simultaneous desorption (2.02 eV) emphasizes the key role played by the surface in H transfer for effective deoxygenation.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b02942

DOI: 10.1021/acs.jpcc.7b02942

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.