Mono and bifunctional pathways of CO2/CH4 reforming over Pt and Rh based catalysts
Mono and bifunctional pathways of CO2/CH4 reforming over Pt and Rh based catalysts
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DOI：
10.1006/jcat.1998.2022
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发表时间：
1998-05-15
影响因子：
7.3
通讯作者：
Lercher, JA
中科院分区：
文献类型：
--
作者：
Bitter, JH;Seshan, K;Lercher, JA
尽管在所用反应条件下形成焦炭的热力学驱动力很高，但Pt/ZrO_2和Rh/γ-Al_2 O_3和ZrO_2是活性和稳定的CO_2/CH_4重整催化剂。使用稳态，瞬态动力学测量和物理化学表征技术表明，催化剂活性是由可用的Pt-ZrO 2周长。甲烷在金属上分解为CHx（x的平均值= 2）和H-2。CO2还原的主要途径是在金属-载体边界附近形成碳酸盐。金属上的碳通过形成CO将碳酸盐还原为甲酸盐。甲酸盐迅速分解为CO和表面羟基。羟基重新结合并形成水或与甲烷进一步反应生成CO和氢气（蒸汽重整）。当甲烷分解速率和碳酸盐还原速率平衡时，催化剂活性保持稳定。相比之下，Rh的活性主要取决于可接近的表面原子的浓度和协调的金属催化的甲烷分解和随后的CO2还原的机制占主导地位。在这种化学反应中，载体起的作用微乎其微。(C)北京：科学出版社.
Despite the high thermodynamic driving force to form coke under the reaction conditions applied Pt/ZrO2 and Rh supported on gamma-Al2O3 and ZrO2 are active and stable catalysts for CO2/CH4 reforming. Using steady state, transient kinetic measurements and physico-chemical characterization techniques have shown that the catalyst activity is determined by the available Pt-ZrO2 perimeter. Methane is decomposed on the metal to CHx (average value of x = 2) and H-2. The main route to CO2 reduction occurs via initial formation of carbonate close to the metal-support boundary. Carbon on the metal reduces that carbonate to formate by forming CO. The formate decomposes rapidly to CO and a surface hydroxyl group. Hydroxyl groups recombine and form water or react further with methane to CO and hydrogen (steam reforming). When the rate of methane decomposition and carbonate reduction are in balance, the catalytic activity remains stable. In contrast, the activity of Rh is mainly determined by the concentration of accessible surface atoms and a concerted metal catalyzed mechanism of methane decomposition and subsequent CO2 reduction dominates. The support plays a minimal role in that chemistry. (C) 1998 Academic Press.