Pt nanoparticles encapsulated in a hollow zeolite microreactor as a highly active and stable catalyst for low-temperature ethanol steam reforming

摘要

High dispersion of Pt nanoparticles encapsulated in hollow Pt@HBZ microreactor has been successfully fabricated through the function of resorcinol-formaldehyde layer during the synthesis process. The low-temperature ethanol steam reforming (LT-ESR) on the Pt@HBZ was studied using various techniques with a focus on the structural characterization of the catalysts, reaction mechanism, and understanding of the structure-activity relationship. The results of steady-state-activity testing, comparisons with those from Pt-beta and Pt-SiO2 catalysts showed that the Pt@HBZ exhibited superior activity, stability and low by-products with negligible deactivation phenomena for 15 h during LT-ESR. The hindering effect of zeolite shell could effectively improve the concentration of relatively large molecules (i.e., ethanol and acetaldehyde) in the hollow micro-environment and promote the molecules reacted with Pt active sites to achieve a complete catalytic conversion. Moreover, due to the "purification effect" for the undesired products (CO, CH4, acetaldehyde and unreacted ethanol), the existence of a large number of microreactors in the reaction system can obtain high-purity hydrogen production.