Accelerated Reaction Exploration across Scales: a Hybrid Operando and Modelling Study of Oxidation Kinetics in Monolayer Tungsten Disulfide

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 multi-step and multi-scale 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 datasets of spatio-temporal 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 this experimental data reveals that oxidative reaction chains leading to W volatilisation 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.