3 years ago

# A potential descriptor for the CO2 hydrogenation to CH4 over Al2O3 supported Ni and Ni-based alloy catalysts

Supported Ni, Cu, Fe, and Ni-M (M=Cu or Fe) catalysts of the same total metal loading and different Ni to M ratios are examined for the CO2 hydrogenation to CH4. Substituting Ni with Cu or Fe in a Ni/Al2O3 catalyst leads to smaller average particle size, sharper particle size distribution and alloy formation, which were determined from transmission electron microscopy (TEM) and X-ray diffraction (XRD). Surface properties of the Ni/Al2O3 and Ni-M/Al2O3 catalysts are found to be different as revealed by hydrogen temperature programmed desorption (H2-TPD). Furthermore, the surface of the supported Ni-Cu catalyst was enriched with Cu. The catalytic activity increases for 75Ni25Fe/Al2O3 relative to Ni/Al2O3, but decreases for 75Ni25Cu/Al2O3. In both these catalysts, the Ni to M ratio was 3:1. The supported Ni and the two Ni3M alloy catalysts are modelled successfully as the shift in 2θ between experimental and simulated XRD pattern were in accordance. Moreover, the trend in shifts in experimental and simulated optimized lattice constants relative to Ni was similar. Density functional theory (DFT) calculations revealed changes in the electronic properties. The electronic properties calculated based on the d-density of states (d-DOS) of surface Ni atoms are the d-band center (ε d ) and number of d-DOS at Fermi level ($N E F$). An excellent correlation between $TOF CH 4$and $N E F$exists, whereas ε d did not satisfactorily capture the trends in$TOF CH 4$. Thus, the $N E F$best describes the catalytic activity trend of the supported Ni and two Ni-based alloy catalysts.

Publisher URL: www.sciencedirect.com/science

DOI: S0926337317306495

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.

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.