Fundamental understanding of C2H4 production from C2H6 oxidation on stochiometric IrO2(110) surface

[Display omitted] •Mechanisms of C2H6 oxidation and C2H4 production on sIrO2(110) were revealed.•Diffusion kinetics is critical to properly understand the simulated TPRS spectra.•The results provide further insights into controlling the reactivity of metal oxides to increase the selectivity. The catalytic oxidative dehydrogenation of alkane can be an attractive way to produce olefines from light alkanes which are major components of natural gas. This study examined C2H6 oxidation on a stochiometric IrO2(110) surface, which has a high potential to produce C2H4 production at a low temperature of ∼ 400 K using density functional theory calculation and microkinetic simulation. The DFT simulation predicted two main complete oxidation mechanisms of dehydrogenation-based oxidation and C2HxO formation-based oxidation. With DFT-derived energetic data, microkinetic simulation for C2H6 oxidation was performed on stochiometric IrO2(110) TPRS spectra. The simulation confirmed that C2H6 oxidation during TPRS mainly follows the dehydrogenation-based complete oxidations (C2H6 → C2H5 → C2H4 → C2H3 → C2H2 → C2H → C2 → C2O → CO + C). In addition, the production of C2H4(g) stems from the cooperative steps of CH bond recombination from C2H3 and subsequent desorption. The computational findings cannot be produced without the proposed concept of a surface diffusion-limited reaction, which can resolve the errors of overestimated rates by the mean field approach. This finding suggests that the diffusion kinetics can be critical for understanding the TPRS features when simulating TPRS spectra by mean field-based microkinetic simulation. Our results provide a solid understanding of C2H6 oxidation and C2H4 production mechanisms on sIrO2(110).