多相光催化分解H2S中阴离子表面活性剂对半导体催化剂CdS表面的影响

研究了在H₂S碱性溶液中,CdS粉末催化剂存在时,光催化分解H₂S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H₂S碱性溶液中,光催化分解H₂S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。

EFFECT OF ANION SURFACTANT ON THE SURFACE OF CdS SEMICONDUCTOR CATALYST IN HETEROGENEOUS PHOTOCATALYTIC CLEAVAGE OF HYDROGEN SULFIDE

Photocatalytic cleavage of hydrogen sulfide into hydrogen and sulfur in aqueous alkaline solution with CdS semiconductor photocatalyst has been studied. It has been examined that sodium lauryl sulfate (SDS) anion surfactant effects on catalyst surface property and catalytic activity in above system. The change of the flatband potential of CdS single crystal electrode is measured with electrochemical method when SDS is added into above system at concentration below the CMC. Thus, It is concluded that the flatband potential of CdS single crystal is shifted toward positive direction in the presence of SDS. The present consequence accords with the decrease of hydrogen quantities evoluted from hydrogen sulfide of photocatalytic cleavage in above system. It is approached that the flatband potential of CdS single crystal electrode is shifted toward positive direction, which is due to competitive adsorption of anion of surfactant and S^2- of the system on the surface of CdS single crystal electrode.