Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (2): 399-406.doi: 10.3866/PKU.WHXB201611092

• ARTICLE • Previous Articles     Next Articles

Facet Effect on Surface Thermodynamic Properties and In-situ Photocatalytic Thermokinetics of Ag3PO4

Ming XIAO1,Zai-Yin HUANG1,2,3,*(),Huan-Feng TANG1,Sang-Ting LU1,Chao LIU1   

  1. 1 College of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Nanning 530006, P. R. China
    2 Key Laboratory of Forest Chemistry and Engineering, Guangxi University for Nationalities, Nanning 530006, P. R. China
    3 Guangxi Colleges and Universities Key Laboratory of Food Safety and Pharmaceutical Analytical Chemistry, Nanning 530006, P. R. China
  • Received:2016-09-08 Published:2017-01-12
  • Contact: Zai-Yin HUANG E-mail:huangzaiyin@163.com
  • Supported by:
    the National Natural Science Foundation of China(21273050,21573048)

Abstract:

Cubic{100}, tetrahedral{111}, and rhombic dodecahedral{110} Ag3PO4 microcrystals were synthesized via a facile wet chemical method. Their components, structure, morphology, and photoelectrical properties were characterized by field emission scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), photocurrent and photoluminescence (PL) analyses. The photocatalytic activity of the Ag3PO4 crystallites with different morphologies were investigated under visible illumination using rhodamine B (RhB) as a target contaminant. Meanwhile, the surface molar Gibbs free energy of the Ag3PO4 crystallites was determined by microcalorimetry via transition state theory and the thermochemical cycle principle. The corresponding values for cubic, tetrahedral, and rhombic dodecahedral microcrystals were 1.2972, 0.9621, and 0.5414 kJ·mol-1, respectively. The heat effect of the in-situ photocatalytic degradation of RhB and heat flow of the stable exothermic stage over the Ag3PO4 crystallites was detected by a LED-photocalorimeter. The results showed that the catalytic activity of Ag3PO4 crystallites and the heat effect and heat flow of the stable exothermic stage were positively correlated with their molar Gibbs free energy.Additionally, the main active species for the photocatalytic degradation of RhB over Ag3PO4 crystallites were determined by trapping experiments and electron paramagnetic resonance (ESR) spectroscopy.

Key words: Ag3PO4, Surface thermodynamics, In-situ photocalorimeter, Photocatalysis, Facet effect

MSC2000: 

  • O642