Lean methane combustion over zeolite-supported Pd catalysts:Structure-performance relationship and deactivation mechanism  

作　　者：Xingyu Liu Jingkun Chen Bowen Han Renna Li Le Shi Zhongbiao Wu Xiaole Weng 

机构地区：[1]Key Laboratory of Environment Remediation and Ecological Health,Ministry of Education,College of Environmental and Resource Sciences,Zhejiang University,Hangzhou 310058,China [2]ZJU-Hangzhou Global Scientific and Technological Innovation Center,Zhejiang University,Hangzhou 311200,China [3]Zhejiang Provincial Engineering Research Centre of Industrial Boiler&Furnace Flue Gas Pollution Control,Hangzhou 310058,China

出　　处：《Journal of Environmental Sciences》2024年第11期128-138,共11页环境科学学报（英文版）

基　　金：supported by the National Key R&D Program of China(No.2022YFC3701603);the National Natural Science Foundation of China(Nos.22106133,52070168);the Key R&D Plan of Zhejiang Province(No.2023C03127);the Fundamental Research Funds for the Central Universities(No.226-2022-00150).

摘　　要：Zeolites are a promising support for Pd catalysts in leanmethane(CH_(4))combustion.Herein,three types of zeolites(H-MOR,H-ZSM-5 and H-Y)were selected to estimate their structural effects and deactivation mechanisms in CH_(4)combustion.We show that variations in zeolite structure and surface acidity led to distinct changes in Pd states.Pd/H-MOR with external high-dispersing Pd nanoparticles exhibited the best apparent activity,with activation energy(Ea)at 73 kJ/mol,while Pd/H-ZSM-5 displayed the highest turnover frequency(TOF)at 19.6×10^(−3)sec^(−1),presumably owing to its large particles with more step sites providing active sites in one particle for CH_(4)activation.Pd/H-Y with dispersed PdO within pore channels and/or Pd2+ions on ion-exchange sites yielded the lowest apparent activity and TOF.Furthermore,Pd/H-MOR and Pd/H-ZSM-5 were both stable under a dry condition,but introducing 3 vol.%H_(2)O caused the CH_(4)conversion rate on Pd/H-MOR drop from 100%to 63%and that on Pd/H-ZSM-5 decreased remarkably from 82%to 36%.The former was shown to originate fromzeolite structural dealumination,and the latter principally owed to Pd aggregation and the loss of active PdO.

关 键 词：Methane combustion Pd catalysts ZEOLITE Structure-performance relationship Deactivation mechanism 

分 类 号：X701[环境科学与工程—环境工程] TQ426[化学工程]