Photothermal Propane Dehydrogenation Catalyzed by VO_x-Doped TiO₂ Nanoparticles

Abstract

Propane direct dehydrogenation (PDH) has received much attention. How to effectively catalyze inert C–H bond activation is of great significance for industrial development. Pt-based catalysts show excellent activity but are limited by their expensive price. Cr-based catalysts are scarcely applied owing to their high toxicity. V-based catalysts are appropriate candidates for their cheap price and low toxicity, but they suffer from high energy consumption. The photothermal synergy effect induced by nonradiative relaxation is expected to make the C–H bond activation and hydrogen coupling process easier compared to bare thermal catalysis. Herein, a set of V/TiO2 nanoscale catalysts were synthesized. The optimized 3 wt % V/TiO2 catalyst (hereafter simplified as 3V) has a particle size of ∼26 nm, achieving a propylene production rate of 342 μmol·g–1·h–1 at 500 °C with UV–vis light radiation, which is 9.2% higher compared with bare thermal conditions. In situ radiation X-ray photoelectron spectroscopy (XPS) shows that photon injection leads to more electron-deficient V atoms (Vδ+, 5 > δ > 3). The strengthened Lewis acidity enhances the C3H8 activation as revealed by kinetic evidence and in situ C3H8-DRIFT measurements. The calculated molecular orbital diagrams show that the V atoms decrease the energy gap between the highest occupied orbital (HOMO) of C3H8 and the lowest unoccupied orbital (LUMO) of the model catalyst. This work describes an efficient photothermal synergy approach, specifically the nonthermal effect for promoting propane dehydrogenation.

Shedding Light on Solar Olefin Synthesis: Advances and Perspectives

“…Within the investigated VO xsupported TiO 2 system, light induces the generation of electrondeficient V δ+ atoms (3 < δ < 5) characterized by augmented Lewis acidity, contributing to heightened efficacy in the photothermal direct dehydrogenation of propane. 67 Another metal oxide-related catalyst, BiOX (X = Cl, Br, and I), comprises alternately stacked layers of [Bi 2 O 2 ] 2+ and double halogen atoms. The halogen atoms manifest catalytic activity for photothermal propylene synthesis.…”

Configuration Effect of Plasmonic Vanadium–Titanium Solid Solutions for Photo-oxidation of Benzyl Alcohol

“…Pure TiO 2 , while being active under UV light, exhibits low BA conversion efficiency and poor BAD selectivity when exposed to visible light due to its wide-ranging band gap energy (3.0–3.5 eV) and the rapid recombination of charge carriers, which generally limits its practical applications. , In this context, VO x –TiO 2 systems are a promising candidate that offers improved performance and are therefore highly desirable alternatives to further enhance the photocatalytic activity for the oxidation of BA to BAD. Several structural configurations of VO x –TiO 2 catalysts have been studied across a range of significant reactions, including the NH 3 selective catalytic reduction, − oxidative dehydrogenation (such as methanol, , ethanol, , cyclohexane, and triethylamine), the combustion of volatile organic compounds (VOCs), and photocatalytic reactions. − In the literature, current research indicates that the structure of the interface and the interaction between the VO x and TiO 2 components vary depending on the configuration of the VO x –TiO 2 composites, which influences their catalytic properties. For instance, VO x species residing on TiO 2 (001) faces exhibit enhanced performance in the selective NO reduction with NH 3 than their corresponding VO x /TiO 2 (101) counterparts.…”

In Situ-Formed PtMn Intermetallic Subnanoclusters on Mn-Doped Mesoporous Al2O3 as Efficient Catalysts for Propane Dehydrogenation

“…Ongoing shale exploration is regarded as a significant opportunity to expand the supply of propane. , Therefore, propane dehydrogenation (PDH) has gained renewed interest in recent years owing to the rising demand for propylene and the increasing availability of propane. Photothermal and photocatalytic strategies were also developed to strengthen the C–H bond activation. − …”