# Tailoring hierarchical ZSM-5 with water-soluble polymers templates for BTX production in methanol-to-aromatics

## TL;DR

Researchers made a better catalyst for turning methanol into BTX aromatics using a one-pot method with water-soluble polymers.

## Contribution

A new one-pot synthesis method using PVP and PEG creates hierarchical ZSM-5 with improved BTX selectivity and stability.

## Key findings

- PVP/ZC achieved 51.3% BTX selectivity and 60.1% overall aromatic selectivity in methanol-to-aromatics reactions.
- The catalyst minimized C9+ byproducts and coke deposition due to optimized acid site distribution and mesoporosity.
- The method is cost-effective and eco-friendly compared to traditional templating techniques.

## Abstract

Hierarchical ZSM-5 zeolites were synthesized by one-pot methods utilizing water-soluble polymers—polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG)—and were compared with a desilicated (DS/ZC) typical microporous ZSM-5 (ZC). Thorough evaluation utilizing XRD, FT-IR, NH3 physisorption, SEM and TEM, ICP-OES, NH3-TPD, and TGA demonstrated that PVP-templated ZSM-5 (PVP/ZC) displayed distinct mesoporosity while maintaining its inherent microporous structure, resulting in a balanced allocation of weak and strong acid sites. All catalysts were assessed in the methanol-to-aromatics (MTA) reaction at 400 °C, with a weight hourly space velocity (WHSV) of 5 h−1 and atmospheric pressure (time on stream = 3 h), resulting in over 99.5% methanol conversion. PVP/ZC attained the highest BTX selectivity of 51.3% and an overall aromatic selectivity of 60.1%, due to its uniform mesoporosity, reduced diffusion pathways along the b-axis, and optimized distribution of acid sites, which collectively minimized secondary C9+ formation (8.8%) and coke deposition (3.27 wt%). The findings indicate that water-soluble polymer templates, specifically PVP, facilitate the customized synthesis of hierarchical ZSM-5 catalysts, which improve BTX production and stability in the MTA process, providing a cost-effective and environmentally friendly alternative to conventional templating and post-synthetic treatments.

Hierarchical ZSM-5 catalysts were synthesized via a one-pot, eco-friendly method using water-soluble polymer templates with high crystallinity and uniform mesoporosity in the MTA reaction.