Tailoring the textural and component properties of Mo-Bi based catalysts for the selective oxidation of tert-butanol to methacrolein by the assistance of polymethymethacrylate

Abstract

Two Mo-Bi based catalysts were prepared with the assistance of PMMA with different sizes, and tested in selective oxidation of tert-butanol to methacrolein. The prepared catalysts, especially C-PM-6 with μm-PMMA, exhibited excellent catalytic performance. Based on the characterization results (BET, MIP, SEM, TEM, XRD, FTIR), the effects of the assistance of PMMA with different sizes were verified. Without modifying the highly active Co₆Fe₄Mo₁₂Bi_1.5O_x phase, the formation of over-oxidation MoO₃ phase was effectively inhibited due to the decomposition of PMMA particles. Importantly, the PMMA assistance could develop hierarchical pore structures, especially mesoporous pores of 6 nm for C-PM-6 catalyst, by preventing primary particles’ agglomeration. Therefore, the mesoporous/macroporous specific surface area obviously increased and thus the abundant active sites were exposed. More importantly, in the newly-formed mesopores pores, there happened Knudsen or molecular diffusion with relatively high mass transfer coefficient, avoiding the overoxidation of target product MAL. From the perspective of reaction engineering, our finding may suggest a new way for developing ultra-high performance commercial selective oxidation catalyst.

Graphical abstract