Hollow‐Fiber‐Supported Gold and Zirconium‐Doped Faujasite Catalytic Membranes for Hydrogen Purification

Abstract

Hollow‐fiber‐supported Au‐Zr/faujasite (FAU, NaY) catalytic membranes were prepared and used as a flow‐through catalytic membrane reactor for CO preferential oxidation (CO‐PROX) in H2‐rich gas. The catalytic membranes were prepared by the modification of FAU zeolite membranes with Zr4+ and Au3+ by ion‐exchange, then activation. The obtained catalytic membranes were characterized by using TEM, X‐ray photoelectron spectroscopy, temperature‐programmed reduction, and temperature‐programmed desorption and their catalytic activity toward CO‐PROX was tested. The results showed that the activation conditions affected the size and oxidation states of the resulting Au nanoparticles strongly, and therefore, affected the catalytic activity strongly. The catalytic activity of the Au nanoparticles can be improved by the doping of Zr to form surface oxygen vacancies and the synergetic effect of Au‐Zr. Meanwhile, the presence of the zeolite framework allows the stabilization of small Au nanoparticles. The Au‐Zr/FAU catalytic membrane prepared under the optimized conditions showed a high catalytic performance (CO conversion above 95 %, turnover frequency>0.4 s−1) and outstanding stability (up to 450 h) below 80 °C, which made it a promising candidate for H2 purification.

Importance of Size and Contact Structure of Gold Nanoparticles for the Genesis of Unique Catalytic Processes

“…Compared to a raw membrane composed by FAU zeolite, CO conversion was enhanced by Zr doping with retention of the selectivity for CO oxidation. 253 2.1.4.6. CO-PROX over Au/Al 2 O 3 .…”

“…Based on these works, ZrO 2 was used as a modifier for application in a membrane-type reactor (Table ). Compared to a raw membrane composed by FAU zeolite, CO conversion was enhanced by Zr doping with retention of the selectivity for CO oxidation …”

FAU zeolite membranes for dewatering of amine‐based post‐combustion CO2 capture solutions

“…Membranes are already reported as process‐boosting technology for selected liquid separation processes to increase the CO 2 loading in the rich stream thereby reducing the energy consumption associated with solvent regeneration. Among them, zeolite membranes, especially FAU, 13‐15 LTA, 16‐18 MFI 19,20 types, have attracted extensive attention in liquid mixture separations such as ethanol/water, isopropanol/water, and dimethyl carbonate/water owing to their well‐defined sub‐nanometer pore size and thermal, chemical, and mechanical stability 21,22 . Among these zeolites, FAU zeolite membranes with 0.74 nm pore size and 12‐membered rings, are well suited for the separation of large molecules which cannot be handled by MFI or LTA with the advantage of its relatively larger pore size.…”