High-performance and stable dendrite-structured mesoporous Zn-Zr/DSMS catalysts for ethanol conversion to 1,3-butadiene

Catalytic conversion of bio-ethanol (EtOH) into 1,3-butadiene (1,3-BD, ETB) represents a low-carbon technology contributing to the sustainable production of renewable 1,3-BD. However, the low selectivity towards 1,3-BD and poor stability of catalysts hinder practical applications of the ETB process. In this work, we presented a novel Zn-Zr catalyst supported on dendrite-structured mesoporous silica (DSMS). Compared to the typical meso- or micro- porous materials such as SBA-15, meso-SiO 2 and Silicate-1 supported catalysts, the Zn-Zr/DSMS catalysts exhibited outstanding catalytic performance and exceptionally high stability in the ETB reaction. Over the representative 0.5%Zn2%Zr/DSMS catalyst, selectivity of 1,3-BD > 65 % and EtOH conversions of 72 %–100 % were obtained at temperatures in a wide range of 350–400 °C. More attractively, the distinguished performance was stable in a long time on stream of 172 h, and able to be effectively restored by calcining the spent catalyst. Systematic characterizations revealed that Zn and Zr species were highly dispersed on the DSMS support nearly at an atomic level, forming abundant Lewis acid sites without Bronsted acidity. This may account for the exceptionally high activity and 1,3-BD selectivity over the 0.5%Zn2%Zr/DSMS catalyst. The unique dendritic structure of the catalyst played important roles in stabilizing the catalytic performance. Correlated to the results of in-situ spectroscopy and conditional experiments, the roles of active sites and the contribution of the catalyst structure were proposed for the ETB process over the Zn-Zr/DSMS catalysts.