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

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 structure-surface 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.