Accessible Chemical Benchmarking of Nanoparticle Growth Using Oxidation-Reduction Potential Sensors

Open-circuit potential (OCP) measurements are an emerging technique for capturing the real time, in situ chemistry of metal nanoparticle syntheses to both (1) understand detailed chemical mechanisms of nanoparticle growth and (2) benchmark the chemistry of nanoparticle formation to improve reproducibility. In this work, we use oxidation-reduction potential (ORP) sensors as an experimentally facile alternative to potentiostat-based methods for acquiring benchmark OCP measurements, which increases the accessibility of this approach to the broader materials chemistry community. We also expand implementation of the OCP method to include non-noble metal materials and more complex reaction conditions by benchmarking copper (Cu) nanoparticle growth at elevated temperatures with both ORP sensors and potentiostat OCP measurements. Additionally, we demonstrate the application of ORP sensors in troubleshooting the detrimental or beneficial influence of impurities in the widely used surfactant cetyltrimethylammonium chloride (CTAC) to ensure reproducible, high quality nanoparticle synthesis. Overall, we establish that ORP sensors are a viable alternative to potentiostat-based OCP measurements for benchmarking and troubleshooting, while also providing important considerations their use in certain mechanistic studies and growth solution chemistries.