This paper describes an innovative system to produce nanoparticles based on the
theory of gas condensation in producing nanoparticles. In a vaccuum environment, the system
used the energy produced by high frequency induction to vaporize a pure zinc rod inside the
crucible. During the vaporization the chamber was filled with He gas, so the high-temperatured
vaporized metal can undergo momentum exchange with He gas and at the same time, induce the
vaporized metal to move to the cold trap. Upon reaching the wall of the cold condenser, the
vaporized metal instantly condensed, forming nanoparticles. The TEM image shows that their
average diameter was 30 nm, and the size was very consistent. In addition, the Zeta potential and
average diameter of the ZnO nanofluid was also measured under different pH conditions to
determine the stability of the ZnO nanofluid. Moreover, in order to verify the practicability of the
fabricated ZnO nanoparticles, the ZnO nanofluid was inspected by UV/Vis absorption spectrum,
and the results show that ZnO nanoparticles absorption ability was within a wavelength range from
350nm to 550nm.