Environmentally friendly electroless plating for Ag/TiO2-coated core–shell magnetic particles using ultrasonic treatment

• A simple and eco-friendly way to synthesize the Fe/TiO2/Ag core–shell magnetic particles is proposed.
• A TiO2-assisted electroless plating of Ag layer without environmentally toxic additives.
• A high degree of morphological control of Ag layer by introducing sonication and adjusting the NH4OH concentration.
• Brilliant white color magnetic particles were obtained without loss of magnetic properties.

In this work, high-reflectance brilliant white color magnetic microspheres comprising a Fe/TiO2/Ag core–shell structure with a continuous, uniform compact silver layer were successfully fabricated by TiO2-assisted electroless plating in a simple and eco-friendly method. The coating procedure for TiO2 and Ag involved a sol–gel reaction and electroless plating with ultrasound treatment. The electroless plating step was carried out in an eco-friendly manner in a single process without environmentally toxic additives. The TiO2 layer was used as a modification layer between the Fe microspheres and the silver layer to improve adhesion. A continuous and compact silver layer could be formed with a high degree of morphological control by introducing ultrasonication and adjusting the ammonium hydroxide concentration.