Identifying Elementary Reaction Kinetics of Heterogeneous Catalytic Mechanisms Using Pseudorandom Binary Sequence-Induced Transients

Abstract

The accurate identification of parameters in microkinetic models is crucial for gaining insights into reaction networks and species surface coverages. This paper explores the improved parameter identifiability achievable through transient kinetic studies compared to steady-state kinetic studies. By utilizing synthetic reactor performance data, we investigate and contrast parameter identifiability using two criteria: the deviation between fitted parameters’ estimates and their preset values, and confidence intervals of the fitted parameters. To enhance practical identifiability, a pseudorandom binary sequence (PRBS) of pulses in the feed concentration of the reactant species is applied to induce transient behavior. Our findings reveal that a finely tuned transient kinetic study outperforms a steady-state study in accurately identifying microkinetic model parameters. Additionally, we demonstrate that the use of PRBS yields more accurate parameter identification compared to the widely used single-step inlet, thereby achieving better practical parameter identifiability. The paper also explores the impact of rate-limiting steps in the microkinetic model and study conditions (including pulse features, sampling time and noise) on the performance of the proposed investigation process toward kinetic parameter identification.