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应用红外光谱研究了CO,NO及其混合气在氧化态CuO/γ-Al_2O_3上的吸附。用XPS测量了表面铜的价态,用XRD分析了催化剂的物相。综合实验结果可知,催化剂体相为CuO,,CuAl_2O_4,,而Cu~+和Cu~(2+)则在样品表面上并存。红外光谱显示,CO在Cu~+上的吸附比在Cu~(2+)上的吸附强,而NO在Cu~(2+)上的吸附比在Cu~+上的吸附强。当CO和NO共存在体系中,CO选择吸附在Cu~+上,而NO选择吸附在Cu~(2+)上。高于室温时,除分子态吸附外,CO在催化剂表面上部分氧化为HCO_3~-,,CO_3~(2-)以及少量HCOO~-,NO吸附,被氧化为NO_3~-。CO和NO共吸附,CO抑制了NO的氧化。
The adsorption of CO, NO and their mixed gases on the oxidation state CuO / γ-Al 2 O 3 was studied by infrared spectroscopy. The valence of the surface copper was measured by XPS and the phase of the catalyst was analyzed by XRD. The experimental results show that the catalyst phase is CuO ,, CuAl_2O_4, while Cu ~ + and Cu ~ (2+) coexist on the sample surface. Infrared spectra showed that the adsorption of CO on Cu ~ + was stronger than that on Cu ~ (2+), while the adsorption of NO on Cu ~ (2+) was stronger than that on Cu ~ +. When CO and NO coexist in the system, CO is selectively adsorbed on Cu ~ +, while NO is selectively adsorbed on Cu ~ (2+). Above room temperature, in addition to molecular adsorption, CO is partially oxidized to HCO 3 -, CO 3 2- and a small amount of HCOO-, adsorbing NO and oxidizing to NO 3 -. CO and NO co-adsorption, CO inhibited NO oxidation.