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考察了光催化剂浓度、粒径、反应温度、乙醇浓度和高温热处理对悬浮Pd/CdS粉末光催化剂的乙醇水溶液可见光催化脱氢活性的影响,得出2.5m gml~(-1)为最佳催化剂浓度,活性达300ml/h·l;温度在305～365K内,反应的表观活化能为36.6kJmol~(-1);在乙醇浓度低于50％时,脱氢反应对乙醇是一级反应;实验证明高温热处理使Pd颗粒向内表面扩散,且强化Pd移去CdS表面的自由电子,两者均提高脱氢活性;得到选择性高于70％的主要氧化产物乙醛;提出了可能的反应机理。
The effects of photocatalyst concentration, particle size, reaction temperature, ethanol concentration and high temperature heat treatment on the photocatalytic dehydrogenation of ethanol in aqueous suspension of Pd / CdS powder photocatalysts were investigated. The optimum catalyst was 2.5 m gml -1 Concentration and activity reached 300ml / h · l. The apparent activation energy of the reaction was 36.6kJmol -1 at temperature of 305 ~ 365K. When the ethanol concentration was lower than 50%, the dehydrogenation reaction was a first order reaction to ethanol ; Experiments show that high temperature heat treatment to Pd particles to the inner surface of the diffusion, and enhanced Pd removal of CdS surface free electrons, both of which increase the dehydrogenation activity; selectivity was higher than 70% of the main oxidation product acetaldehyde; proposed possible Reaction mechanism.