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用质谱检测的程序升温脱附技术研究了甲醇在Pd-La_2O_3/SiO_2催化剂上的脱附和分解行为,高温He处理过的催化剂基本上不吸附氢,但对甲醇分解仍有一定的活性和较高的选择性。H_2还原后的催化剂有较大的吸附氢的能力,对甲醇分解的活性也较高,但分解产物中CO_2的含量明显增加,LaO的助催化作用主要是提高催化剂表面甲醇吸附物类的浓度和减弱CO的吸附强度,并因此抑制它的歧化反应。 DO对吸附实验表明甲醇在催化剂表面的吸附有可逆和不可逆两种形式,对于可逆吸附的甲醇,其后DO对吸附所引起的置换效应尤为明显。
The desorption and decomposition behavior of methanol on Pd-La 2 O 3 / SiO 2 catalyst was studied by mass spectrometry temperature-programmed desorption. The catalyst treated with high-temperature He basically did not adsorb hydrogen, but still had certain activity and higher activity for methanol decomposition The selectivity. H 2 reduction of the catalyst has a larger capacity of hydrogen adsorption, methanol decomposition activity is also higher, but the decomposition product CO 2 content was significantly increased, LaO promoter role is mainly to improve the catalyst surface methanol adsorption species concentration and Weaken the adsorption strength of CO, and thus suppress its disproportionation reaction. DO adsorption experiment showed that the adsorption of methanol on the catalyst surface was reversible and irreversible. For the reversibly adsorbed methanol, the displacement effect of DO on the adsorption was especially obvious.