Rational Design of Non-noble-metal Heterogeneous Catalysts for the Production of Renewable Fuels and Valuable Chemicals via a Combined Experimental and Theoretical Approach

The aim of this study was to utilize a combination of quantum chemical modeling calculation and state of the art experimental techniques to develop inexpensive non-noble metal catalysts for contemporary reactions. Specific focus was placed on understanding how to systematically tune the surface chemical reactivity as a function of the compositional constitution within the solids, e.g. transition metal + post-transition metal and transition metal + p-block element materials. The efforts upon developing fundamental understandings on surface chemistry drive the discovery of catalysts that exhibit appropriate reactivity to enable selectively activating C–C, C–O, and C–H bonds within linear and aromatic unsaturated hydrocarbons.The work presented here provides two unique platforms to show how to rationally design in-expensive non-noble metal catalysts. In the first example, a computational surface science study was performed upon understanding several fundamental bonding and surface chemistry factors of TM ceramics and their connections to reaction mechanisms of biomass transformation towards benzene production. Our studies show that the general surface reactivity towards carbon, oxygen, and hydrogen can be systematically manipulated as a function of composition change within TM ceramics and can dictate catalytic activity and selectivity. For selective biomass deoxygenation catalysts, an enhanced surface reactivity towards oxygen and a balanced reactivity towards carbon and hydrogen are needed. Our calculations demonstrated that several 1st row transition metal (TM) nitrides and phosphides that display relatively appropriate surface reactivity exhibited more reasonable energetics in the deoxygenation of biomass-model compound, guaiacol.In the second example, we utilized a combination of DFT calculations and surface composition controlled synthesis approach to design highly selective (up 95%) supported Ni+Ga intermetallic compounds for propane dehydrogenation. Our studies demonstrated that the surface composition of supported Ni+Ga IMCs can be manipulated as a function of support selection, actual loading of Ni and Ga, chemical potential of reduction gas, and annealing condition. These aspects allowed us to investigate how the surface composition change affects catalytic activity and selectivity experimentally as well as to model the surface in the theoretical study to understand the effect of surface composition change on local electronic structure and on the general surface chemistry towards carbon that can affect the energetics of reaction mechanisms.