Synthesis of Silica-Coated Copper Nanoparticles and its Application to Red Color Glaze

A core-shell structure of Cu@SiO2, namely, silica-coated Cu nanoparticles, was synthesized by a simple liquid phase reaction. The reaction bath was optimized by evaluating the balance between the dissolution behavior of Cu nanoparticles and the deposition rate of SiO2 shells for coating. The Cu nanoparticles were fabricated by an electroless deposition method. The deposition and dissolution behaviors of Cu were quantitatively evaluated by quartz crystal microbalance (QCM) measurements, combined with the reducing ability evaluated by the mixed potential measurements. SiO2 shells were synthesized by a sol-gel process of tetraethyl orthosilicate (TEOS). The optimal responsiveness bath condition was also elucidated by the QCM measurement to evaluate the deposition rate of SiO2 shells, which was much faster than the dissolution rate of Cu nanoparticles, indicating that the SiO2 shells sufficiently coated the Cu nanoparticles. The stability of annealed Cu@SiO2 nanoparticles was considerably increased and by using them, the red color glaze is achieved in easy and safe way.