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研究了在H_2S碱性溶液中,CdS粉末催化剂存在时,光催化分解H_2S释氢和生成硫反应。考察了阴离子表面活性剂——十二烷基硫酸钠(SDS)对催化剂的表面性质和催化活性的影响。通过模拟该反应体系,用电化学方法测定了单晶CdS电极在上述反应体系中加入SDS(浓度低于临界胶团浓度CMC值)后的平带电位的变化。结果表明:单晶CdS电极的平带电位,由于该体系加入SDS而正移,与n型多晶半导体CdS在加入SDS的H_2S碱性溶液中,光催化分解H_2S的释氢量减少相一致。并探讨了在该体系中,由于表面活性剂的阴离子与S~(2-)在单晶CdS电极表面上的竞争吸附,而引起单晶CdS电极的平带电位正移。
The photocatalytic decomposition of H 2 S to hydrogen and the formation of sulfur reaction were studied in the presence of CdS powder catalyst in H 2 S alkaline solution. The effect of anionic surfactant sodium dodecyl sulfate (SDS) on the surface properties and catalytic activity of the catalyst was investigated. By simulating the reaction system, the change of flat band potential of single crystal CdS electrode was measured by electrochemical method after SDS was added into the above reaction system (the concentration was lower than the critical micelle concentration CMC value). The results show that the flat band potential of single crystal CdS electrode is positive because of the addition of SDS. It is in agreement with the reduction of H 2 S release amount by photocatalytic decomposition of H 2 S in n-type polycrystalline semiconductor CdS solution. In this system, the positive shift of the flatband potential of single crystal CdS electrode was induced due to the competitive adsorption between the anionic surfactant and S 2- on the surface of single crystal CdS electrode.