Does CO2 dissociatively adsorb on Cu surfaces
Does CO2 dissociatively adsorb on Cu surfaces
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DOI：
10.1088/0953-8984/1/sb/026
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发表时间：
1989-10
期刊：
影响因子：
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通讯作者：
J. Nakamura;JoséA. Rodriguez;C. Campbell
中科院分区：
文献类型：
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作者：
J. Nakamura;JoséA. Rodriguez;C. Campbell
在超高真空表面分析室和附加的高压池中研究了CO2与清洁Cu（110）表面的相互作用。在110 K和250 K下，暴露量高达350 L时，没有测量到CO2的吸附或解离。在400-600 K下暴露于65 - 650 Torr的CO2导致根据反应CO2.g到COg+Oa的原子吸附氧的积累，其速率随温度增加（约16 kcal mol-1）并随反应时间降低，在p（2*1）-O覆盖层中饱和。所观察到的解离反应概率约为10-9-10-11（每次与表面的碰撞）的CO2有利地与基于吸附氧的热力学和已知的逆反应动力学的预测相比：COg+Oa到CO2.g。速率也合理地接近于在基于Cu的催化剂上的逆水煤气变换反应中报道的CO2的反应概率，这表明涉及CO2的解离吸附的催化氧化还原机制，随后通过与H2反应消耗所得的Oa。结果还表明，在催化甲醇合成条件下，需要超过约100的CO2：CO比率在铜表面上产生显著的氧浓度。作者无法在Cu（110）上从Oa + CO2产生表面碳酸盐。
The interactions of CO2 with a clean Cu(110) surface have been studied both in an ultrahigh-vacuum surface analytical chamber and in an attached, high-pressure cell. No adsorption or dissociation of CO2 was measured for exposures up to 350 L at 110 K and 250 K. Exposures of 65 to 650 Torr of CO2 at 400-600 K led to the build-up of atomically adsorbed oxygen according to the reaction CO2.g to COg+Oa at a rate which increased with temperature ( approximately 16 kcal mol-1) and decreased with reaction time, saturating in a p(2*1)-O overlayer. The observed dissociative reaction probabilities for CO2 of approximately 10-9-10-11 (per collision with the surface) are favorably compared with predictions based upon the thermodynamics of adsorbed oxygen and the known kinetics of the reverse reaction: COg+Oa to CO2.g. The rates are also reasonably close to the reaction probability for CO2 reported in the reverse water-gas shift reaction over Cu-based catalysts, which suggests a catalytic redox mechanism involving the dissociative adsorption of CO2, followed by consumption of the resulting Oa by reaction with H2. The results also show that CO2:CO ratios in excess of approximately 100 would be required to produce significant oxygen concentrations on copper surfaces under catalytic methanol synthesis conditions. The authors were unable to produce surface carbonate from Oa plus CO2 on Cu(110).