AgSb_(2)O_(5.18)/Ag/Ag_(2)S等离子体-Z型异质结构造及氧化还原性能

Plasmonic Z-type heterostructures structure and redox property of AgSb_(2)O_(5.18)/Ag/Ag_(2)S nanocomposites

以L-半胱氨酸、KSbO_(6)H_(6)和AgNO_(3)为原料,利用水热法一步合成了AgSb_(2)O_(5.18)/Ag/Ag_(2)S粉末材料,在250℃下焙烧得到试样AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250;提出了AgSb_(2)O_(5.18)/Ag/Ag_(2)S等离子体-Z型异质结模型,并基于该模型揭示了电子-空穴转移规律。采用XRD、SEM、HRTEM、XPS、UV-Vis、电子自旋共振(ESR)等方法对试样的物相、形貌和结构特征等进行表征。表征结果显示,AgSb_(2)O_(5.18)/Ag/Ag_(2)S的粒径约为50 nm,粒径分布较均匀;AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250颗粒形貌不规则,有新的Ag相生成;AgSb_(2)O_(5.18),Ag_(2)S,AgSb_(2)O_(5.18)/Ag/Ag_(2)S,AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250的吸收带边分别为460,272,260,245 nm;AgSb_(2)O_(5.18)和Ag_(2)S的能量带隙分别为2.60,4.95 eV。实验结果表明,在可见光下,试样AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250能产生最强的DMPO-O_(2)^(-)·和DMPO-OH·(DMPO为5,5-二甲基-1-吡咯啉-N-氧化物)自由基ESR信号峰,表明AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250具有最强的氧化和还原能力。

AgSb_(2)O_(5.18)/Ag/Ag_(2)S was synthesized by hydrothermal method using L-cysteine,KSbO_(6)H_(6) and AgNO_(3) as raw materials.AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250 was obtained by calcining AgSb_(2)O_(5.18)/Ag/Ag_(2)S at 250℃.XRD,SEM,HRTEM,XPS,UV-Vis,electron spin resonance(ESR)methods were used to characterize the phase,morphology and structural characteristics of the sample.A plasmonic Z-type heterostructure model of AgSb_(2)O_(5.18)/Ag/Ag_(2)S was proposed.Based on the model,the electron-hole transfer law of AgSb_(2)O_(5.18)/Ag/Ag_(2)S is found.The results show that the size of AgSb_(2)O_(5.18)/Ag/Ag_(2)S is about 50 nm and the particle size distribution is uniform.The particles of AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250 are irregular in shape.Some new metallic silver phase is formed in the process of calcination.The absorption bands are located at 460,272,260,245 nm for AgSb_(2)O_(5.18),Ag_(2)S,AgSb_(2)O_(5.18)/Ag/Ag_(2)S,AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250.The energy bandgap of AgSb_(2)O_(5.18) and Ag_(2)S are 2.60,4.95 eV.Under visible light,there are the strongest DMPO-O_(2)^(-)·and DMPO-OH·(DMPO:5,5-dimethyl-1-pyrroline-N-oxide)ESR corresponding peaks caused by AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250,which indicated that AgSb_(2)O_(5.18)/Ag/Ag_(2)S-250 had the strongest redox properties.