Preparation and stability of silver/kerosene nanofluids

Abstract

A series of silver nanoparticles surface-coated with di-n-dodecyldithiophosphate, di-n-cetyldithiophosphate, or di-n-octadecyldithiophosphate have been prepared and have good dispersity in alkanes or kerosene. Stable silver nanofluids can be formed in alkanes or kerosene with the surface-coated silver nanoparticles. Thermal stability of the silver nanofluids has been measured at different temperatures. The effects of the silver nanoparticles on the thermal oxidation of kerosene have been investigated at different temperatures. The coatings can be released from the surface of the silver nanoparticles above 150°C, giving oxygen access to the silver core and inhibiting the kerosene oxidized by oxygen.

Figure 1

XRD patterns of surface-coated silver nanoparticles with dialkyl dithiophosphates.

Figure 2

TEM and SAED images of surface-coated silver nanoparticles at 60 °C. (a) AgDDP12, (b) AgDDP16, and (c) AgDDP18.

Figure 3

TEM images of surface-coated silver nanoparticles prepared at 100 °C. (a) AgDDP12, (b) AgDDP16, and (c) AgDDP18.

Figure 4

UV-vis spectra of different silver nanoparticles. (a) Prepared at 60°C and (b) 100°C.

Figure 5

Thermal stability time as a function of temperature for the silver nanofluids.

Figure 6

Comparisons of hydroperoxide concentrations in silver-kerosene nanofluids and blank kerosene thermally oxidized at different temperatures. (a) 120°C, (b) 140°C, and (c) 150°C.