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The catalytic properties of monometallic and bimetallic Ru and Mo phosphides were evaluated for their ability to selectively hydrogenate furfural to furfuryl alcohol. Monometallic MoP showed high selectivity (98%) towards furfuryl alcohol, while RuP and Ru 2 P exhibited lower selectivity at comparable conversion. Bimetallic promotional effects were observed with Ru 1.0 Mo 1.0 P, as the pseudo-first order reaction rate constant for furfural hydrogenation to furfuryl alcohol, k 1 , was at least 5× higher than MoP, RuP, and Ru 2 P, while maintaining a 99% selectivity. Composition-directed catalytic studies of Ru x Mo 2−x P (0.8 < x < 1.2) provided evidence that Ru rich compositions positively influence k 1 , but not the selectivity. The rate constant ratio k 1 /( k 2 + k 3 ) for furfuryl alcohol production compared to methyl furan ( k 2 ) and tetrahyrofurfuryl alcohol ( k 3 ) followed the trend of Ru 1.0 Mo 1.0 P > Ru 1.2 Mo 0.8 P > MoP > Ru 0.8 Mo 1.2 P > RuP > Ru 2 P. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to examine the configuration of adsorbed furfural on the synthesized catalysts, but themore »results were inconclusive and no correlation could be found with the selectivity due to the possible IR inactive surface modes with furfural adsorption. However, gas phase density functional theory calculations suggested the x = 1.0 material in Ru x Mo 2−x P (0.8 < x < 1.2) had the most favorable furfural adsorption energy. Experimentally, we also observed that the solvent greatly influenced both the conversion and selectivity, where isopropanol provided the highest selectivity to furfuryl alcohol. Finally, recycling experiments showed a 12% decrease in k 1 after 3 cycles without any regeneration, but the activity could be fully recovered through a re-reduction step.« less

Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO₂conversion into value-added chemicals and fuels, CH₄activation into hydrogen, higher hydrocarbons or oxygenates, and NH₃synthesis. Other applications are already more established, such as for air pollution control, e.g. volatile organic compound remediation, particulate matter and NO_xremoval. In addition, plasma is also very promising for catalyst synthesis and treatment. Plasma catalysis clearly has benefits over ‘conventional’ catalysis, as outlined in the Introduction. However, a better insight into the underlying physical and chemical processes is crucial. This can be obtained by experiments applying diagnostics, studying both the chemical processes at the catalyst surface and the physicochemical mechanisms of plasma-catalyst interactions, as well as by computer modeling. The key challenge is to design cost-effective, highly active and stable catalysts tailored to the plasma environment. Therefore, insight from thermal catalysis as well as electro- and photocatalysis is crucial. All these aspects are covered in this Roadmap paper, written by specialists in their field, presenting the state-of-the-art, the current and future challenges, as well as the advances in science and technology needed to meet these challenges.

Catalytic hydrodeoxygenation (HDO) of phenolics is a necessary step for upgrading bio-oils to transportation fuels. Bimetallic catalysts offer the potential of increased activities and selectivities for desired products. Adding non-metallic elements, such as phosphorous, allows for charge distribution between the metal and nonmetal atoms, which improves Lewis acid character of catalytic surfaces. This work utilizes experimental and density functional theory (DFT) based calculations to identify potential C–O bond cleavage pathways and product selectivities for HDO reactions on FeMoP, RuMoP, and NiMoP catalysts. Our work demonstrates that FeMoP catalyst favors direct deoxygenation pathway due to a lower activation energy barrier for C–O bond cleavage whereas RuMoP and NiMoP catalysts promote ring hydrogenation first, followed by the cleavage of C–O bond. The Bader charge analysis indicates that for these catalytic systems Mo δ+ site bears a large positive charge which acts as a Lewis acid site for HDO reactions. Overall, we find that trends in the experimental product selectivities are in good agreement with that predicted with DFT calculations.