Zn and Si transport in dual-functioning catalyst for conversion of synthesis gas to dimethyl ether

•Balanced domain sizes optimize the hybrid dimethyl ether catalyst stability.•Analysis by microprobe line scan and SEM showed interface migration of Zn and Si.•Activity testing applying constant conversion minimized kinetic model dependency.•Lower degree of Zn intrusion in SiAl conjugates higher coarse pellet stability.•The results guide in design of best catalysts for direct dimethyl ether synthesis.