Assessing the Nature of Active Sites on Nanodiamonds as Metal-Free Catalysts for the EB-to-ST Direct Dehydrogenation Using a Catalytic Approach

The oxygen-free alkane direct dehydrogenation (DDH) is a greener, safer, and more selective alternative to oxygen co-fed conditions produce olefins. Carbon-based catalysts have significantly boosted this branch of catalysis by providing cheaper, robust, durable, environmentally friendly single-phase materials as valuable substitutes variety alkaline- or alkaline earth-promoted transition metal oxides. In particular, nanodiamonds (NDs) rank among the most effective metal-free systems investigated so far for alkane-to-alkene conversion under either oxidative conditions. Although important structural/compositional/activity relationships class sp2/sp3 C-hybrids already been unveiled exothermic (ODH) process, many issues still remain be addressed challenging process. mechanism nature active sites in carbon employed steam-free DDH controversial matter debate because lack studies harsher operative typically required endothermic Here, we report on chemico-physical morphological properties nanodiamond samples before after their use model ethylbenzene-to-styrene using combination catalytic outcomes with extensive characterization these led us speculate oxidized carbons catalytically Density functional theory (DFT) calculations finally used corroborate our hypotheses, support role ortho-quinone (oQ) groups at edge cubic-sp3 NDs source (active sites) DDH.