Estudo do efeito do cloreto em catalisadores de paládio usando a análise no infravermelho e de fotoelétrons excitados por raios x

Química Nova

Eduardo V. Cunha²  Flávio Faccin²  Celso C. Moro²  Edilson V. Benvenutti²  Sandra C. De Castro¹ 

[1] ,Universidade Federal do Rio Grande do Sul Instituto de Química Porto Alegre RS

关键词: chloride poisoning effect;    infrared;    XPS;   

DOI  :  10.1590/S0100-40422002000300011

来源: SciELO

【 摘 要 】

Chloride poisoning is known as having an inhibitor effect in the activity of metal catalysis. In this work in situ infrared spectroscopy (FTIR) of adsorbed carbon monoxide and x-ray photoelectron spectroscopy (XPS) were used to investigate the effect of chloride presence in the electronic metal density in the d subshell of palladium dispersed on alumina. The chloride poisoning effect was interpreted as an electronic effect since a weak back-bonded Pd-CO was formed due to the decrease in the electronic density of the d subshell of palladium, which could be also detected by the higher Pd 3d5/2 binding energy in the chloride presence. A similar poisoning effect was also observed for chloride free Pd/Al2O3 reduced at 500 ºC, and it was interpreted based on the interaction of metal with the alumina surface. The use of molybdena/alumina binary system as support, yield a contrary effect due to the metal-support interaction.

【 授权许可】

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