Optimizing H-B-ZSM-5 catalyst for efficient methanol-to-propylene conversion via precise control of NaOH-TPABr interaction

Abstract

This study investigates the effects of boron (B) and crucial interplay between NaOH and TPABr during the synthesis of seed-induced H-B-ZSM-5 for designing effective MTP catalysts. Various characterization techniques were employed to examine the impact of these factors on the physiochemical properties of the synthesized catalysts. The findings reveal that boron incorporation leads to an 81 % increase in catalyst stability and a 5.5 % increase in selectivity to light olefins. A critical interplay between NaOH concentration and TPABr content was also found in optimizing crystallinity, morphology, acidity and surface area. The crystallinity, Al distribution homogeneity, and average pore size initially increase before decreasing with increasing NaOH concentration. The research highlights the pivotal role of TPABr, which interacts with NaOH to profoundly impact catalyst performance. The synthesized catalyst H-B-ZSM-5, prepared with TPABr/20SiO₂ = 0.65 and Na₂O/20SiO₂ = 1.69, exhibits excellent performance, achieving 99 % conversion and 83 % light olefin selectivity with minimal byproduct formation during a 170-h test at a high WHSV_methanol equal to 8 h⁻¹.