Performance of PEG-Templated B2O3/SiO2–TiO2 Catalysts for the OxidativeDehydrogenation of Light Alkanes

Abstract The oxidative dehydrogenation (ODH) of light alkanes offers an energy-efficient route to olefins. Boron-based catalysts, while highly selective, often suffer from limited activity and issues of active-site aggregation. Herein, we report a rational design of high-performance B2O3/SiO2–TiO2 catalysts through polyethylene glycol (PEG) templating. By varying the PEG molecular weight, we achieve superior dispersion of active boron species and tailored pore structures. The optimized catalyst (PEG-4000 modified, 30 wt % B2O3, TiO2/SiO2 = 2/1) delivers markedly improved performance, reaching propane and ethane conversions of ∼66% and ∼71% with olefin selectivities of ∼71% and ∼73%, respectively. To decipher the complex interplay of variables, we combine extensive catalytic testing with machine learning (ML) analysis, quantitatively identifying reaction temperature and B2O3 loading as the dominant factors. Furthermore, density functional theory (DFT) calculations indicate local structural coupling between BOx and the SiO2–TiO2 support and different adsorption strengths of the alkanes and O2 at a representative interface. In the context of the currently accepted surface-initiated gas-phase radical mechanism for boron-based ODH, these results provide qualitative information about the local surface environment that may be relevant to radical initiation. This work demonstrates an effective PEG-assisted synthesis strategy and, more importantly, establishes a multifaceted experimental-theoretical framework to uncover key governing factors, offering concrete guidelines for the development of advanced boron-based ODH catalysts.