Predictive Chemical Kinetic Modeling of Pt-Catalyzed Dry Methane Reforming

TL;DR

This study develops a detailed automated microkinetic model for Pt-catalyzed dry methane reforming, revealing key reaction pathways, bottlenecks, and operational regimes to guide catalyst design across a broad temperature range.

Contribution

First application of automated microkinetic modeling to Pt-catalyzed DRM, integrating sensitivity, flux, and surface analysis for catalyst optimization.

Findings

Model accurately predicts methane and CO2 conversion across temperatures.

Identifies OCX as a critical bottleneck intermediate.

Defines three operational regimes with distinct kinetic controls.

Abstract

Dry reforming of methane (DRM) over platinum catalysts offers a promising route for CO2 utilization and syngas (H2/CO) production, a versatile feedstock for synthetic fuels. This study employs automated chemical kinetic model generation to present a detailed microkinetic mechanism for Pt-catalyzed DRM between 700-1100 K, identifying key reaction pathways and kinetic limitations through sensitivity analysis. Model predictions of CH4 and CO2 conversion and syngas production closely match fixed-bed experimental data across the entire temperature range and varied feed ratios. Our predictive reaction network reveals that OCX serves as a critical bottleneck intermediate for cooperative CH4 and CO2 activation. While CO desorption (OCX <=> CO + X) was identified as the most influential step with strong negative sensitivity toward methane concentration, OCX regeneration (CO2X + CX <=> 2OCX) inhibits methane conversion by maintaining surface saturation. Methane activation follows sequential C-H scissions (CH4X -> CH3X -> CH2X -> CHX -> CX), while CO2 activation proceeds predominantly via a hydrogen-mediated carboxyl route (CO2X + HX -> COOHX -> COX + OHX). Three operational regimes were identified: low-temperature desorption-limited kinetics (700-850 K), transitional pathway activation (850-950 K), and high-temperature distributed control with carbon management challenges (950-1300 K). These insights provide design principles for platinum-based DRM catalysts, emphasizing temperature-specific optimization strategies. This is the first study to apply fully automated microkinetic model generation to Pt-catalyzed DRM, integrating sensitivity analysis, flux analysis, and surface speciation for catalyst design.