Synthesis of Porous and Highly Crystallinity Vanadium Phosphorus Oxide Catalysts by Multifunctional Biomass-Based Deep Eutectic Solvents

Abstract

Deep eutectic solvents (DESs) as a novel class of ionic liquid analogues has been widely used in various fields. Herein, a multifunctional biomass-based DES composed of choline chloride (ChCl) and glucose (GLU) was synthesized and used for the modification of vanadium phosphorus oxide (VPO) catalyst, which is the sole catalyst for the selective oxidation of n-butane to maleic anhydride (MA) in industry. The DES is more green, cost-effective and efficient compared with traditional modifier (metal inorganics and organic polymers). A combination of structure and catalytic performance was investigated in detail to deeply understand its functions. Initially, this DES plays the role of structure directing agent at the stage of precursor synthesis, which can induce the formation of active plane and obtain highly crystalline precursors. Accordingly, the active phase with highly crystalline was obtained after the activation of precursors. Additionally, the DES was decomposed during the precursors activation, resulting in the formation of porous structure around 20 nm on the active plane. Besides this, the surface chemical state including the valence state and acid–base property was changed significantly due to the function of DES. All of these lead to about an 11% increase of MA mass yield, which has great significance to the high value utilization of low carbon alkanes.

Mono-, Bi-, and Tri-Metallic DES Are Prepared from Nb, Zr, and Mo for n-Butane Selective Oxidation via VPO Catalyst

“…Herein, peaks were determined using Avantage software and the curve was fitted via Gaussian function. In literature exhibiting the binding energies associated with vanadium, characteristic peaks (V2p 3/2 ) are reported repeatedly (Figure 16a) [26,27]. The V2p 3/2 characteristic results obtained from the fitted curve correspond to the whole catalyst vanadium species V 5+ (VOPO 4 ) and V 4+ ((VO) 2 P 2 O 7 ).…”

“…Additionally, these dopants have a bad effect on the environment. Therefore, we prepared a eutectic solvent from various metal dopants for a VPO catalyst [25][26][27]. The issues of poor crystallinity and limited active sites were solved by organic modifications and template strategies.…”

“…They found that the active sites of the VPO catalyst were responsible for enhancing the catalytic performance [25]. Further, the addition of ChCl into glucose (Glu) (ChCl/Glu) DES also improved the selective MA yield via the development of a crystalline and porous VPO catalyst [26]. Moreover, the polyols-based DES acted as a structure-directing agent in VPO synthesis [27].…”

Deep Eutectic Solvents: A New Class of Versatile Liquids

“…A number of studies report results from theory (Hayyan, Tuinier) , as well as classical and ab initio molecular dynamics simulations (Atilhan, Aparicio, Kashyap, Hung, Chaumont, Banerjee, Pádua, Kirchner, Zahn, Paul, and Balasubramanian) − to shed light on the structure, thermodynamics, and dynamics of DESs. X-ray and neutron scattering studies, sometimes in conjunction with molecular simulations, are reported to better understand DES structure (Triolo, Russina, Lewandowski, Brown, Atkin, Maginn, and Edler). − Various spectroscopic techniques are used, sometimes in conjunction with simulations, to study solvation structure, dynamics, and diffusion (Mitra, Sen, Biswas, Pandey, Kuroda, Gurkan, and Baker). − Other studies have focused on catalysis (Liu, Zhang), the effect of water on properties (Gutiérrez, Panzer), , electrodeposition (Magagnin), and fundamental thermodynamics and phase behavior (Coutinho, Marrucho). , …”

“…26−30 Various spectroscopic techniques are used, sometimes in conjunction with simulations, to study solvation structure, dynamics, and diffusion (Mitra, Sen, Biswas, Pandey, Kuroda, Gurkan, and Baker). 31−37 Other studies have focused on catalysis (Liu, Zhang), 38 the effect of water on properties (Gutieŕrez, Panzer), 39,40 electrodeposition (Magagnin), 41 and fundamental thermodynamics and phase behavior (Coutinho, Marrucho). 42,43 The field of deep eutectic solvents is growing rapidly, and new DES compositions are being discovered along with the growth of a greater understanding of the physical chemistry of these fascinating fluids.…”