Size-Controllable Synthesis of Cu Nanoparticles via Hydrogen Reduction at Low Temperatures.

The general polyol methods used for synthesizing copper nanoparticles (CuNPs) usually require high temperatures to ignite the reduction reaction, which leads to the difficulty of controlling the particle size. Herein, a new polyol method for the size-controllable synthesis of CuNPs at low temperatures by adopting high-pressure hydrogen as the reductant is verified. It is proven that hydrogen is capable to reductively produce CuNPs at temperatures as low as 120 °C. The size of the CuNPs can be controlled between 19.29 nm and 140.46 nm by adjusting the hydrogen pressure, the reaction temperature, and duration. An empirical relationship between temperature and particle size is proposed. This work verifies a low-temperature strategy to synthesize nanoparticles with good size-controllability.