基于电导法结合热力学理论研究球状纳米硫化镉热力学性质的尺寸效应和温度效应

Size and temperature effects on the thermodynamic functions of spherical nano−CdS investigated using conductance method and thermodynamic theories

表面结构对纳米粒子的物理和化学性质是至关重要的,为了设计出具有理想表面性能的纳米材料,需要精确的表面热力学参数来确定纳米粒子的构效关系.通过微乳法合成5种粒度在32~119 nm球状硫化镉(CdS),利用溶解热力学原理及热力学基本理论,通过实验获取了不同尺寸纳米CdS的溶解热力学函数,建立不同尺寸纳米球摩尔表面热力学和偏摩尔表面热力学模型理论,结合纳米和块体材料性质差异和热化学循环理论,推导出摩尔表面热力学函数、摩尔表面热容,分析讨论了硫化镉纳米球热力学性质的尺寸及温度效应的规律和原因.

It is well accepted that surface structures are critical for the physical and chemical properties of nanoparticles.Precise surface thermodynamic parameters of nanomaterials are needed to generate the structuresurface activity relationship in order to design nanomaterials with desired surface properties.In this study,spherical cadmium sulfide(CdS)of nanometer size(32 to 119 nm)were synthesized by microemulsion method.By using the principle of dissolved thermodynamics and basic thermodynamic theories,the dissolved thermodynamic functions of nano−CdS with different sizes were obtained experimentally.By establishing models of molar surface thermodynamics and partial molar surface thermodynamics for nanospheres of different sizes and considering the different properties between nano and bulk materials as well as the thermochemical cycle theories,the surface thermodynamic functions,molar surface isobaric heat capacity were deduced.The law and reason of size and temperature effects on thermodynamic functions of nano−CdS were discussed.