Abstract
Palladium-exchanged chabazite(Pd-CHA)zeolites as passive NOx adsorbers(PNAs)enable efficient pu-rification of nitrogen oxides(NOx)in cold-start diesel exhausts.Their commercial application,however,is limited by the lack of facile preparation method.Here,high-performance CHA-type Pd-SAPO-34 zeo-lite was synthesized by a modified solid-state ion exchange(SSIE)method using PdO as Pd precursor,and demonstrated superior PNA performance as compared to Pd-SAPO-34 prepared by conventional wet-chemistry strategies.Structural characterization using Raman spectroscopy and X-ray diffraction revealed that the SSIE method avoided water-induced damage to the zeolite framework during Pd loading.Mech-anistic investigations on the SSIE process by in situ infrared spectroscopy and X-ray photoelectron spec-troscopy disclosed that,while PdO precursor was mainly converted to Pd2+cations coordinated to the zeolite framework by consuming the-OH groups of the zeolite,a portion of PdO could also undergo thermal decomposition to form highly dispersed Pd0 clusters in the pore channels.This simplified and scalable SSIE method paves a new way for the cost-effective synthesis of defect-free high-performance Pd-SAPO-34 zeolites as PNA catalysts.
基金项目
国家自然科学基金(21976058)
广东省自然科学基金(2023A1515011682)
中央高校基本科研业务费专项(2022ZYGXZR018)
National Engineering Laboratory for Mobile Source Emis-sion Control Technology(NELMS2020A10)
Pearl River Talent Recruitment Program of Guangdong Province(2019QN01L170)
Innovation & En-trepreneurship Talent Program of Shaoguan City()
NETL
NSTL
万方数据