Modulating accessibility, acidity and hydrogenation functions on mesoporous NiO1-x/Y-zeolite for vanillin hydrodeoxygenation

A 10 wt % NiO on mesoporous Y-zeolite catalyst was studied for vanillin hydrodeoxygenation. Vanillin, having aldehyde, ether and hydroxyl groups is a representative moiety of lignin. Characterization results indicated that alkali-treated zeolites featured mesoporous craters and, after NiO impregnation, yielded a bifunctional acid-hydrogenation catalyst. Mesoporous Y-zeolite allows a greater accessibility of vanillin to Brønsted acid sites (BAS) giving one order of magnitude higher activity in comparison with pristine Y-zeolite, besides of eliminating methoxy group on the former, but not on the later. Nonetheless, alkali-treatment of Y-zeolite should be done with low alkali concentration to have a balance between craterization and zeolite's crystalline structure. Y-zeolite having both micro- and mesoporous are a more effective choice than untreated Y-zeolite. Methoxy groups can be eliminated through protonation on BAS without aromatic ring hydrogenation, providing aromatic phenolic compounds at low hydrogen consumption. [Display omitted] •Alkali-treated desilicated Y-zeolite featured mesoporous craters.•NiO deposited on micro-mesoporous zeolite results in acid-hydrogenation catalyst.•Desilicated Y-zeolite has tetrahedrally coordinated Al with Brönsted Acidity.•Micro-mesoporous zeolite shows 8.6 times higher activity than untreated Y-zeolite.•Carbonyl and Methoxy in vanillin are removed without aromatic ring hydrogenation.