Adsorption of Biomass-Derived Products on MoO₃: Hydrogen Bonding Interactions under the Spotlight

We performed a computational study on the interaction of O-containing compounds coming from biomass with a catalytic surface of MoO₃. The addition of H atoms on the metal oxide surface mimics different scenarios of its exposure to the ambient or protons coming from biomass. Representative compounds from fatty acids (from triacylglycerides) and aromatics (from lignin) were adsorbed on the metal oxide surfaces. We covered the complete H surface coverage, and the adsorbed molecules showed structural changes due to the interactions in turn. The driven force interactions in this process is hydrogen bonding, which reveals the complexity in biomass processing. H-bonds were fully characterized by the electron density and its Laplacian where bond critical points are present. These topological properties allow us to understand the correlation between the adsorption energies and the strength on each adsorption site. We also computed the relative Gibbs energies and harmonic oscillator model of aromaticity index of the adsorbed molecules to get more insights into their stability.