Abstract
A biomass-templated Nb/ZnO nanocatalyst, synthesized by a mechanochemical-assisted and sacrificial template method, promotes catalytic conversion of levulinic acid to N-heterocycles under solvent-free conditions, exhibiting an outstanding catalytic performance in terms of conversion (94.5 %) and selectivity (97.4 %) towards one particular N-heterocycle compound.
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•A biomass-templated Nb/ZnO nanocatalyst was synthesized.•Highly active catalyst for the conversion of levulinic acid to N-heterocycles.•Critical role of niobium was found for LA conversion.•Optimum 10 %Nb/ZnO exhibited high conversion (94.5 %) and selectivity (97.4 %).
Herein, we report a Nb/ZnO nanocatalyst for the efficient conversion of levulinic acid, a platform molecule easily obtained from lignocellulosic biomass, to N-heterocycles under mild reaction conditions and the absence of solvent. Nb/ZnO nanocatalysts were synthesized by a mechanochemical-assisted and sacrificial template method, involving orange peel valorization toward nanostructured materials. Two different synthetic approaches, either one-step or two-step, as well as the amount of niobium deposited onto the ZnO support were investigated in order to obtain the nanocatalyst with the optimal catalytic properties. Results revealed the critical role of the niobium for LA conversion. The nanocatalyst containing 10 wt% of niobium and prepared following a two-step approach (10 %Nb/ZnO_2) exhibited the best catalytic performance with a 94.5% of conversion and 97.4% of selectivity towards one specific N-heterocycle compound. This work exemplifies the possibility of sustainable production of value-added compounds, in particular N-heterocycles, from biomass-derived feedstocks by playing with the design of improved catalysts. Importantly, this research area provides sustainable alternatives to the current chemical industry that is heavily dependent on fossil fuels.