A method for forming metal nanoparticles on halloysite nanotubes. The method provides a water-based suspension solution containing about 0.002% to about 0.1% by weight of halloysite nanotubes. The suspension solution is maintained between about 2° C. and about 98° C. and under sufficient mixing that the nanotubes are maintained in substantially constant suspension. At least one positive and at least one negative metal electrode is positioned in the suspension solution, wherein the metal electrodes are at least 98% pure metal. A voltage is maintained across the electrodes of between about 10 and about 300 volts for a time sufficient to form metal ions on at least about 10% of a surface of the halloysite nanotubes.
