摘要
本文用TEM、HOT、XPS实验技术研究了不同含量PtO_2在γ-Al_2O_3载体上的分散状态,以及Pt/γ-Al_2O_3体系氧化还原过程中PtO_2及Pt的状态变化。结果表明,PtO_2可在载体上单层分散,其最大单层分散量(阈值)为0.0246g PtO_2/100m^2γ-Al_2O_3,当PtO_2量超过阈值时,出现剩余PtO_2物相。单层分散在载体上的PtO_2能被H_2还原为分散度很高的金属Pt,当它经使用老化后又能再经氧化转变成PtO_2,这种新生的PtO_2能够再度自发单层分散在载体上。此现象有助于说明Pt载负型催化剂氧化再生机理。
The dispersion states of PtO_2 supported on γ-Al_2O_3 with different contents and the state changes of PtO_2 and Pt in the oxidation-reduction process of the Pt/γ-Al_2O_3 system have been studied by using XRD, TEM and XPS. The results show that PtO_2 can disperse as a monolayer onto the surface of γ-Al_2O_3. A monolayer dispersion capacity (threshold) of 0.0246g PtO_2/100m^2 γ-Al_2O_3 surface is observed. When the PtO_2 content in a PtO_2/γ-Al_2O_3 sample exceeds the threshold, residual PrO_2 phase appears. After reduction by hydrogen, the monolayer dispersed PtO_2 forms Pt particles smaller than that from PrO_2 phase. When supported Pt particles are oxidized to form PRO_2, it will disperse onto the support as monolayer again. These phenomena explain the regeneration mechanism of Pt/γ-Al_2O_3 catalyst.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
1992年第3期8-14,共7页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家自然科学基金
