Supported transition metal (Mo, W) carbide and nitride catalysts for lignin hydrodeoxygenation: interplay of supports, structure, and catalysis

Lignin exhibits a good prospect as an abundant and sustainable raw material for the production of value-added chemicals. Transition metal carbides and nitrides are very suitable for aromatics production from lignin ascribed to their high hydrodeoxygenation activity, low ring hydrogenation activity, low cost and good stability. However, a comprehensive summary and critical analysis have not been reported yet. In this regard, this minireview summarized the recent advances of transition metal (Mo, W) carbide- and nitride-catalyzed hydrodeoxygenation of lignin or its model compounds, aiming to provide an in-depth understanding of the interplay of support, structure, and catalysis. We focused on the changes in catalyst performance with their different structures, such as different crystal phases and supports, the type and amount of doping metal, etc. Also, some constructive suggestions are put forward on the selection of the catalyst system which is most suitable for the target product and the further improvement of hydrodeoxygenation performance. In-depth understanding of the structure-performance relationship for transition metal (Mo, W) carbide- and nitride-catalyzed lignin hydrodeoxygenation was summarized.