B–O Oligomers or Ring Species in AlB₂: Which is More Selective for Propane Oxidative Dehydrogenation?

Abstract

B-based catalysts are widely studied in the oxidative dehydrogenation of propane (ODHP) owing to their high selectivity. Correspondingly, two species, B−O oligomers and rings, have been recognized as active centers in B-based catalysts. To answer the essential question of whether B−O oligomers or ring species are more selective for ODHP, two AlB 2 catalysts enriched with B−O rings (R-AlB 2 ) and abundant B(OH) x O 3−x oligomers (O-AlB 2 ) were designed and compared herein. When tested in ODHP, R-AlB 2 exhibits an olefin yield of 30.2% at 500 °C, which is 2.3 times that of O-AlB 2 . Additionally, R-AlB 2 was stable for up to 200 h without deterioration. Multiple characterizations, including in situ Fourier transform infrared spectroscopy and theoretical calculations, demonstrate that B−O rings are more advantageous for producing propylene (C 3 = ) via a dehydration pathway with lower energy barriers and ethylene (C 2 = ) via two other reaction pathways (direct cracking of propane and oxidative coupling of methyl) B(OH) x O 3−x is primarily responsible for producing few C 3 = .

Chemically exfoliated boron nanosheets for efficient oxidative dehydrogenation of propane

“…FT-IR spectra were obtained to probe the oxy-functional groups such as B-O and B-OH that have been reported as active sites for ODHP over boron-based catalysts. 9,41,42 Compared with MgB 2 (Fig. S14 †), some new stretching vibrations were observed in Mg-BNSs (Fig.…”

Niobium Boride/Graphene Directing High-Performance Lithium–Sulfur Batteries Derived from Favorable Surface Passivation

“…And two pairs of peaks at 207.1 and 209.7 eV are related to Nb 5+ , which are attributed to Nb–O bonds owing to the inevitable contamination of the surface exposure to air. Further, the bands at ∼682 and 1402 cm –1 in the FTIR spectrum can correspond to Nb–O and B–O stretching modes − (Figure S18). To corroborate the above bonding assignments based on the XPS spectra, we have further performed Raman measurements of NbB 2 (Figure c).…”

Unlocking the Chain‐Walking Process in Gold Catalysis**

“…Over the past two decades, several unconventional and challenging reactions have been realized by employing this technique. For instance, Zhu, [2] He, [3] Engle, [4] Yuan/Zhang, [5] and others [6] utilized the chain‐walking process for the remote C−H functionalization reactions (Scheme 1b). Advancing forward, Kochi, [7] Yin, [8] Lin/Yao, [9] Wang, [10] Zhou, [11] and Giri [12] group eloquently showcased its applicability in achieving the non‐classical and challenging remote 1,n‐difunctionalization of alkenes (Scheme 1c).…”