Graphene oxide-assisted fast synthesis of hierarchical ZSM-11 with superior performance for benzene alkylation

Abstract

Fast synthesis of zeolite with hydrothermal method is a challengeable topic. In this work, we reduced the crystallization time to ~1/3 of conventional method by adding a small amount of graphene oxide (GO) into ZSM-11 synthesis gel. The embedment of GO into ZSM-11 crystal was confirmed by XPS, TG, and Raman spectra, while it modified morphology, porosities, component, and surface acidity of ZSM-11 as characterized by SEM, TEM, XRF, N2-physisorbtion, NH3-TPD, and Py-IR. The non-classical nucleation, which governed the required crystallization time, was further proposed and evidenced by both experimental observations and molecular dynamic modeling. It clearly illustrated the positive role of GO on promoting the formation of meta-stable phase during non-classic nucleation, resulting into much shorter crystallization time. GO embedded ZSM-11 demonstrated high activity (reaction rate and TOF), improved selectivity, and superior stability for benzene alkylation with ethanol, which can be attributed to the regulated surface acidity and diffusion properties. This work opens up a new perspective to synthesize ZSM-11 zeolite with superior catalytic performance in a highly efficient and environmental manner.