Efficient in situ cell modeling boosts catalytic microkinetics quantification by transient infrared spectroscopy

Operando diffuse reflectance infrared Fourier transform spectroscopy, when combined with transient kinetics approaches, enables quantification of key intermediates and intrinsic kinetics over industrial heterogeneous catalysts. However, these measurements are blurred by residual species within in situ cells due to complex nonideal flow during rapid gas switching. Herein, we model the cell using ideal reactor combinations, with parameters fitted via residence time distribution experiments for two commercial cells by an in‐house code. Then, steady‐state isotope transient kinetic analysis was conducted for methanol steam reforming to derive rate constants for crucial surface reactions. Our approach estimated microkinetic parameters precisely and consistently across both cell designs, prevailing over conventional methods that produced inconsistent results. This analytical framework not only boosts the effectiveness of existing in situ cells in catalytic process development, but also lays a critical foundation for the design and optimization of next‐generation spectroscopic systems.