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应用微量吸附量热技术研究了室温下 H2 ,CO,O2 和 C2 H4 在 m( Pd) /m( Si O2 ) =2 % ,m( Pd,Cu) /m( Si O2 ) [n( Pd) /n( Cu) =1 /1 ]=2 % ,m( Pd,Cu) /m( Si O2 ) [n( Pd) /n( Cu) =1 /4]=2 %和 m( Cu) /m( Si O2 ) =8%催化剂表面的吸附性能 ,并考察了 O2 对 C2 H4 吸附性能的影响 .结果表明 ,Pd-Cu/Si O2 具有与 Pd/Si O2数量相近的表面 Pd原子 .加入 Cu可使 Pd对 H2 和 CO的强吸附位数目相对减少 ,弱吸附位数目相对增加 .Pd增加了 H2 在 Cu/Si O2 催化剂表面的吸附量 ,加速了 O2 在 Cu表面的吸附速率 .Pd原子和 Cu原子在Pd-Cu/Si O2 中混合均匀且分散良好 .乙烯在 Pd/Si O2 表面吸附有乙川、 di-σ和π吸附态 .Cu的加入可抑制乙烯在 Pd表面解离吸附为乙川 ,促进了非解离的 di-σ和 π吸附态形成 .乙烯在室温下可与 Pd表面吸附氧发生氧化反应 ,加入 Cu可降低 Pd表面吸附氧的氧化活性 ,使乙烯在 Pd表面有效活化
The effects of the molar ratios of H2, CO, O2 and C2 H4 at m / Pd (Si O2) = 2% and Pd / Cu / / (Cu) = 1/1] = 2%, m (Pd, Cu) / m (Si O2) [n (Pd) / n (Cu) = 1/4] = 2% and m The results show that Pd-Cu / Si O2 has the same surface Pd atomic number as Pd / Si O2, and the addition of Cu The number of strong adsorption sites of Pd on H2 and CO decreased and the number of weak adsorption sites increased relatively.Pd increased the adsorption amount of H2 on the surface of Cu / Si O2 catalyst and accelerated the adsorption rate of O2 on Cu surface. Cu atoms are uniformly mixed and dispersed well in Pd-Cu / Si O2. Ethylene adsorption on the surface of Pd / Si O2 with ethane, di-σ and π adsorption states. The addition of Cu can inhibit the dissociative adsorption of ethylene on the Pd surface, Promoted the formation of non-dissociated di-σ and π adsorption states. Ethylene can react with adsorbed oxygen on Pd surface at room temperature. Adding Cu can reduce the oxidation activity of adsorbed oxygen on Pd surface and effectively activate ethylene on Pd surface