Automated Electroanalysis Accelerates the Discovery of Concerted Proton–Electron Transfer

Electroanalysis of reaction kinetics is a time-tested method for the mechanistic inquiry of proton-coupled electron transfer (PCET), yet the tedious manual nature of its experimental operation reduces the analytical tool's research throughput and impedes its broader application. Here we report an automated, high-throughput electrochemical platform for reliable electroanalysis of PCET reactions with [Os^II(bpy)₂(py)(H₂O)]²⁺ as the model system. The automated system increases the research throughput by more than 10-fold and accelerates our discovery of a concerted PCET pathway facilitated by a proposed adduct formation between the redox center and phosphate as a proton donor/acceptor. As opposed to at least 3 years of manual experimentation, automated electroanalysis completed the inquiry within 1,580 h (66 days) by analyzing more than 43,800 voltammograms and quantifying approximately 730 kinetic rate constants. Such experimental "big data" opens up new lines of inquiry that were not feasible before. Automating electroanalysis accelerates discoveries for a wide range of critical applications in energy conversion and storage.