Oxygen content as a variable to control product selectivity in hydrodeoxygenation reactions on molybdenum carbide catalysts

Oxygen-treatment of as-synthesized molybdenum carbide at 296 K-423 K and subsequent temperature-programmed-surface-reaction with hydrogen was utilized to obtain oxygen-modified Mo2C (O:Mo-bulk = 0.002 for Fresh-Mo2C to O:Mo-bulk = 0.276 for Mo2C oxygen treated at 423 K) formulations. Benzene selectivity decreased from 97% at O:Mo-bulk = 0.002 to 18% at O:Mo-bulk = 0.276 while phenol selectivity concurrently increased from 0.2% at O:Mo-bulk = 0.002 to 81% at O:Mo-bulk = 0.276 in reactions of anisole/hydrogen mixtures at atmospheric pressure and 423 K showing that O* content can be used to tune the product selectivity in hydrodeoxygenation reactions on transition metal carbides. This change in selectivity can plausibly be ascribed to the formation of MoOx/MoOxCy species that disrupts ensembles required for selective aromatic C-O bond cleavage. (C) 2018 Elsevier Ltd. All rights reserved.