Accelerated Reaction Exploration across Scales: A Hybrid Operando and Modeling Study of Oxidation Kinetics in...

The commercialization of emerging materials is hindered by the empirical nature of process development, with the underpinning solid-state reaction kinetics remaining elusive due to their inherent multistep and multiscale character and the vast configurational and parameter space. We combine high-throughput operando scanning electron microscopy (OSEM) with extended classical continuum and phase-field simulations and atomistic machine-learned interatomic potential (MLIP) surrogate models to demonstrate effective foundational reaction exploration, using thermal oxidation of chemical-vapor-deposited monolayer WS₂ across a temperature range of 450-680 °C as our benchmark reaction. OSEM provides statistically relevant reaction data sets of spatiotemporal basal plane nucleation kinetics and propagation of tens of thousands of individual 1D reaction facets, revealing time-dependent rates. By extending Avrami theory and employing a calibrated phase-field model, we extract an apparent nucleation barrier of 1.1 eV and show that the complex rate behavior arises from mixed reaction-diffusion control. Atomistic reaction exploration via MLIPs guided by these experimental data reveals that oxidative reaction chains leading to W volatilization and etch pit formation are driven not by the most common sulfur or substitutional oxygen point defects but by more complex defects such as W vacancies. MLIP diffusion barrier screening identifies the role of chemisorbed hydroxyl species for this reaction scenario, while systematic screening of 1D edge configurations and their terminations uncovers the structural origins of the pronounced in-plane reaction anisotropies. We discuss the potential of our synergistic approach to effectively bring experimental and computational approaches closer together and accelerate critically required process discovery for advanced materials.