A solvation strategy for fabricating acid-base sites on metals/ZSM-5 towards dehydration of high-water-content methanol to dimethyl ether

In the process of modified basic NaZSM-5 precursor by its impregnating in M(NO₃)_n (M = Al, Cu, Fe, Co, Ni, Cr, Mn, Zn) or SnCl₄ acidic aqueous solutions, we shed light on the solvation effect of M^x+ cations on surface acid-base strength, and further on enhanced catalytic reactivity. The obtained results indicated that M(Sn, Fe, Cr)/NaZSM-5 prepared with pK_a values of the metal salts <4 present high catalytic reactivity due to their stronger solvation prone to produce acid-base site balance on the surface. To further understand the influence of solvation, the catalytic performance of Sn/NaZSM-5 for methanol, particularly the water-containing methanol dehydration was examined, achieving high conversion and selectivity for high-water-content methanol dehydration. Meanwhile, the catalytic stability test of the catalyst was carried out and above 1000 h run lifetime was actualized without the catalyst surface composition and structure changed.