不同载体对甲醇分解钯催化剂性能的影响

Effect of Different Supports on Performance of Palladium Methanol Decomposition Catalyst

摘要:

用浸渍法制备了Pd/γ-Al2O3和Pd/Ce0.65Zr0.35O2 2种甲醇分解催化剂。采用XRD，NH3-TPD (NH3-Temperature- Programmed Desorption)，XPS及H2-TPR (H2-Temperature-Programmed-Redution)等手段对2种催化剂的结构和性能进行表征，并考察了催化剂上甲醇低温分解的活性。结果表明，Pd/Ce0.65Zr0.35O2催化剂具有较弱的表面酸性及良好的低温还原性能；XPS结果表明2种催化剂中的Pd均以氧化态形式存在，并且Pd在Ce0.65Zr0.35O2固溶体上呈高度分散状态，Pd与Ce间具有较强的相互作用。结合活性考察可知，Pd+的存在有利于甲醇的分解。Pd/Ce0.65Zr0.35O2催化剂具有高的催化活性，220 ℃时甲醇转化率接近100%。

Abstract:

Two kinds of palladium methanol decomposition catalysts were prepared by immersion method with γ-Al2O3 and Ce0.65Zr0.35O2 as supports, respectively. XRD, XPS, H2-TPR (H2-Temperature-Programmed-Redution) and NH3-TPD (NH3-Temperature- Programmed Desorption) techniques were used to study the microstructure and performance of catalyst samples and the activity of methanol low-temperature decomposition for the catalysts was also investigated. Testing results show that the Pd/Ce0.65Zr0.35O2 catalyst possesses weak surface acidity and good low-temperature reducibility. XPS results confirm that palladium of the two catalysts exist as oxidation state. Combining with catalytic activity, it can be known that Pd+ is advantageous in the methanol decomposition. High dispersion of palladium in ceria-zirconia solid solution and strong interaction between Pd and supports can decrease activation energy which results in high catalytic activity for methanol decomposition. The conversion of methanol nearly achieved 100% at 220 ℃ for Pd/Ce0.65Zr0.35O2.