Zeolites are crystalline materials widely used in applications like ion exchange, adsorption, and catalysis. However, their microporous structure restricts their ability to process larger molecules. To overcome this challenge, researchers have developed ZMQ-1, a zeolite that incorporates intrinsic mesopores—pores larger than 20 Å—while preserving both stability and acidity.

Previous attempts to create mesoporous zeolites struggled with issues like structural instability and reduced acidity, rendering them unsuitable for industrial use. ZMQ-1, however, presents a solution to these problems. The researchers utilized a phosphonium-based organic structure-directing agent (OSDA) to form the mesoporous framework. Unlike traditional ammonium-based OSDAs, phosphonium-based OSDAs offer a stronger positive charge and greater stability, which allows for the synthesis of more robust mesoporous structures. The crystallization of ZMQ-1 was accomplished through hydrothermal synthesis with tunable silicon-to-aluminum (Si/Al) ratios, enabling the zeolite to be customized for specific applications.

“ZMQ-1 is the first aluminosilicate zeolite with an intrinsic meso-microporous channel system,” said Prof. Peng Lu, co-corresponding author from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT), Chinese Academy of Sciences. “Unlike other mesoporous materials that lack stability after removing organic templates, the interconnected 28-ring channels in ZMQ-1 represent a major leap in zeolite design.”

The team used three-dimensional electron diffraction (3D ED) and scanning transmission electron microscopy (STEM) to reveal the unique structure of ZMQ-1. The 28-ring mesopores are connected by 10-ring microporous windows, creating a highly efficient channel system. This design enables the diffusion of both large and small molecules, overcoming the diffusion limitations of traditional zeolites. As a result, ZMQ-1 is particularly effective in catalytic cracking of heavy oil.

To assess the performance of ZMQ-1, the researchers conducted catalytic cracking experiments using vacuum gasoil (VGO), a key feedstock in petroleum refining. The results revealed that ZMQ-1 achieved a high VGO conversion rate, comparable to that of commercial USY and Beta zeolites. Furthermore, it outperformed MCM-41, a widely recognized mesoporous molecular sieve, in both conversion efficiency and stability.

Phosphorus-containing ZMQ-1 showed twice the selectivity for diesel production while significantly reducing coke formation compared to its commercial counterparts. This combination of higher diesel yield and lower coke generation led to an impressive overall fuel selectivity (gasoline and diesel combined) of 80%, a substantial improvement over conventional zeolites.

These results demonstrate that phosphorus-containing ZMQ-1 is capable of efficiently converting heavy hydrocarbons into valuable fuels. Its unique meso-microporous structure maximizes the yield of desired products while minimizing undesirable by-products, making it a promising candidate for advancing catalytic processes in the petrochemical industry.

ZMQ-1 represents a major step forward in the development of more efficient and sustainable chemical processes. By overcoming the persistent challenges of pore size limitations and structural instability, this breakthrough opens new opportunities for applications in heavy oil cracking and green energy conversion. With its demonstrated potential in catalytic applications, ZMQ-1 offers a promising solution for improving the efficiency of industrial catalytic processes and advancing the future of sustainable energy.

By Impact Lab