The efficient conversion of combined feedstocks into target chemicals such as light olefins or aromatics is a key objective in catalysis research. A new study published on Dec 1, 2025 in Frontiers of Chemical Science and Engineering provides a blueprint for catalyst design by linking surface properties directly to product outcomes. Conducted by researchers from Shenyang University of Chemical Technology and the Dalian Institute of Chemical Physics, CAS, the work clarifies the roles of outer surface acidity and reactant molecular size in the co-conversion process.
The study focused on the co-conversion of methanol with a series of straight-chain alkanes. A key finding is the decisive role of the catalyst's outer surface acidity. On a catalyst with weak outer surface acidity, as the carbon chain length of the alkane increased, the yield of valuable C₂–C₄ olefins rose significantly. This is because the milder acidity suppresses undesirable secondary reactions, allowing the primary cracking products to persist as light olefins. The weak acidity also reduces the formation of C₁–C₄ alkane by-products, further improving olefin selectivity.
Conversely, on a catalyst with strong outer surface acidity, the story changes. The robust acidic sites drive intermediate olefins into further reactions such as isomerization, cyclization, and oligomerization. This leads to a steep decline in light olefin yield and a marked increase in the production of aromatics like benzene, toluene, and xylene, as well as heavier hydrocarbon species. The study quantitatively shows this trade-off, providing a clear lever for chemists to pull depending on the target product slate.
Beyond acidity, the physical size of the reactant molecules relative to the catalyst's pores emerged as another critical factor. While n-hexadecane is restricted to external cracking on the microsphere catalyst, pure ZSM-5 zeolite allows long-chain alkanes (>C₁₀) to adjust their molecular configuration at high temperature and enter the pores for internal cracking. This underscores the impact of catalyst forming on the final pore accessibility and cracking behavior.
By linking acid strength distribution and pore accessibility of catalyst directly to macroscopic reaction outcomes, this work provides a clear, experimentally grounded blueprint for designing more efficient and selective catalysts for the integrated conversion feedstocks.

DOI
10.1007/s11705-026-2635-9