A Contactless Method for Measuring the Redox Potentials\nof Metal Nanoparticles

The standard redox\npotentials of metal nanoparticles are important\nfor understanding their chemical properties. Traditionally, these\nredox potentials are measured by using voltammetry. Although voltammetry\nis fast and cost-effective, loading or landing the nanoparticles on\nelectrodes alters their electrochemical properties, posing a challenge\nfor accurately determining their intrinsic redox potentials. Here,\na contactless method was developed utilizing chemical assays and the\nNernst equation to measure the standard reduction potentials of gold\nnanoparticles in their colloidal state. To showcase the versatility\nand accuracy of this Nernstian approach, the reduction potentials\nwere measured for a size range of 5.0–73 nm, revealing their\nscaling law and dependence on the nanoparticle surface energy.