First-Principles Investigation of Hydroxyl Species Formation on β-MnO₂(110) for Catalytic Oxidation Applications

Hydroxyl (OH) species play a critical role in several oxidative catalysis processes, including the oxidation of 5-hydroxymethylfurfural (HMF) to produce valuable compounds like 2,5-furandicarboxylic acid (FDCA). High OH coverage on metal oxide surfaces significantly enhanced catalytic activity. Herein, we investigated OH coverage on the β-MnO₂(110) surface generated through the decomposition of oxidant molecules (O₂, H₂O₂, and tert-butyl hydroperoxide, TBHP) using density functional theory (DFT) calculations and ab initio thermodynamic modeling. We studied the kinetics and thermodynamics aspects of OH formation pathways, focusing on direct O-O and C-O bond cleavages and reactions with H₂O, both in gas and solvent environments. Computations reveal that TBHP and H₂O₂ exhibit lower dissociation barriers and favorable thermodynamics than O₂, yielding higher OH coverage under relevant reaction conditions. Phase diagrams constructed from thermodynamic models reveal that TBHP maintains high OH coverage across a broader temperature range, suggesting its potential as an efficient oxidant for catalytic applications. These insights support the development of β-MnO₂ catalysts tailored for oxidation processes by guiding oxidant selection and reaction conditions.