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用XRD相定量法测定了CuO在γ—Al_2O_3表面的分散阈值,它相当于100米~2γ-Al_2O_3能分散0.039克铜。在阈值之下,CuO都能以Cu~(2+)分散开,在阈值以上,出现晶相,但分散开的Cu~(2+)数不变。用TPD法研究了CO在CuO/γ-Al_2O_3上的吸附。在阈值以下,吸附量随CuO含量的增加而增加;在阈值处,吸附量最大即1米~2样品约吸附1.1×10~(18)、个CO分子;阈值以上,吸附量不变。CO以线型方式吸附于表面Cu~(2+)上,形成6-π表面络合物。CO与Cu的最大分子数比大于1。且随表面Cu~(2+)密度的增加而下降。
The dispersion threshold of CuO on γ-Al_2O_3 surface was determined by XRD method. It is equivalent to 0.039 g copper dispersed in 100 ~ 2 γ-Al_2O_3. Below the threshold, CuO can be dispersed in Cu ~ (2+), above which the crystalline phase appears but the number of Cu ~ (2+) dispersed does not change. The adsorption of CO on CuO / γ-Al 2 O 3 was studied by TPD method. Below the threshold, the amount of adsorption increased with the increase of CuO content. At the threshold, the adsorption capacity was about 1.1 × 10 ~ (18) CO molecules at the maximum of 1m ~ 2. Above the threshold, the adsorption capacity remained unchanged. CO is linearly adsorbed on the Cu 2+ surface to form a 6-π surface complex. The maximum molecular ratio of CO to Cu is greater than one. And decreased with the increase of surface Cu ~ (2+) density.