Understanding the oxidative dehydrogenation of ethyl lactate to ethyl pyruvate over vanadia/titania

Zhang, Wei; Innocenti, Giada; Ferbinţeanu, Marilena; Ramos‐Fernández, Enrique V.; Sepúlveda-Escribano, A.; Wu, Haihong; Cavani, Fabrizio; Rothenberg, Gadi; Shiju, N. Raveendran

doi:10.1039/c7cy02309j

Cited by 32 publications

(24 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the pyruvate is easily overoxidized on the catalyst surface at such high temperatures, lowering the product selectivity. 33 A series of control experiments confirmed that the reaction is in the kinetic regime, with no mass-transfer limitations. Then, we measured the selectivity to ethyl pyruvate against ethyl lactate conversion over phytic acid-derived VOPO 4 nanosheets (PTA–VOPO 4 ) and phosphoric acid-derived 3D VOPO 4 nanoparticles (PA–VOPO 4 ) ( Figure 3 a).…”

Section: Resultsmentioning

confidence: 76%

“…Elsewhere, we have reported that the oxidation of ethyl lactate follows a Mars–van Krevelen mechanism: ethyl lactate adsorbed on the catalytic surface is oxidized by the lattice oxygen, and then, the resultant oxygen vacancies are replenished by gas-phase oxygen during the oxidation reaction. 33 Thus, both surface lattice oxygens and oxygen vacancies play key roles in aerobic oxidation of ethyl lactate to ethyl pyruvate. These two species can be roughly estimated from the O 1s XPS spectrum ( Figure 4 c): the peak at ∼532.5 eV can be attributed to the lattice oxygen (O I ) and the peak at ∼531.0 eV can be attributed to the adsorbed oxygen species at the vacancy sites (O II ).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Self-Exfoliated Synthesis of Transition Metal Phosphate Nanolayers for Selective Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate

et al. 2020

Self Cite

View full text Add to dashboard Cite

Two-dimensional (2D) transition metal nanosheets are promising catalysts because of the enhanced exposure of the active species compared to their 3D counterparts. Here, we report a simple, scalable, and reproducible strategy to prepare 2D phosphate nanosheets by forming a layered structure in situ from phytic acid (PTA) and transition metal precursors. Controlled combustion of the organic groups of PTA results in interlayer carbon, which keeps the layers apart during the formation of phosphate, and the removal of this carbon results in ultrathin nanosheets with controllable layers. Applying this concept to vanadyl phosphate synthesis, we show that the method yields 2D ultrathin nanosheets of the orthorhombic β-form, exposing abundant V 4+ /V 5+ redox sites and oxygen vacancies. We demonstrate the high catalytic activity of this material in the vapor-phase aerobic oxidation of ethyl lactate to ethyl pyruvate. Importantly, these β-VOPO 4 compounds do not get hydrated, thereby reducing the competing hydrolysis reaction by water byproducts. The result has superior selectivity to ethyl pyruvate compared to analogous vanadyl phosphates. The catalysts are highly stable, maintaining a steady-state conversion of ∼90% (with >80% selectivity) for at least 80 h on stream. This “self-exfoliated” synthesis protocol opens opportunities for preparing structurally diverse metal phosphates for catalysis and other applications.

show abstract

Section: Resultsmentioning

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Self-Exfoliated Synthesis of Transition Metal Phosphate Nanolayers for Selective Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…As shown in Figure b, the spectra of O 1s in V‐NCNs‐x can be fitted into three peaks: the peaks at 530.5 eV and 531.7 eV represent the vanadia lattice oxygen (O I ) and the chemisorbed oxygen(O II ), respectively; The peak at 533.7 eV was attributed to the pyridinic N‐oxygen or carbonyl oxygen (O III ), in which the pyridinic N‐oxide species dominate at high temperature (>800 °C) . In our case, the atom ratio of O III /(O I +O II +O III ) in these series increased as follows: V‐NCNs‐900 (0.33)>V‐NCNs‐800 (0.30)>V‐NCNs‐700 (0.19)>V‐NCNs‐600 (0.11), in good agreement with the catalytic efficiency in Figure a.…”

Section: Methodsmentioning

confidence: 68%

“…Addressing these problems, we studied a series of supported vanadium oxides in the conversion of lactates to pyruvates, and found that titania‐supported vanadia outperformed other supports . We also found that adding a small amount of activated carbon can inhibit the ethyl pyruvate polymerization in the titania‐catalyzed oxidation of ethyl lactate .…”

Section: Methodsmentioning

confidence: 99%

Selective Aerobic Oxidation of Lactate to Pyruvate Catalyzed by Vanadium‐Nitrogen‐Doped Carbon Nanosheets

et al. 2019

Self Cite

View full text Add to dashboard Cite

The catalytic oxidative dehydrogenation of lactates with molecular oxygen is a promising yet challenging route for producing high‐value pyruvates from biomass. Here we report a simple synthetic strategy for preparing nitrogen‐doped carbon nanosheets (NCNs) starting from two abundant precursors, cheap melamine and glucose, and using a simple thermal‐annealing process. The resulting NCNs feature numerous edges and holes for anchoring vanadium oxides (V‐NCNs). This creates cooperative catalytic sites that boost the catalytic oxidation of ethyl lactate to ethyl pyruvate. Additionally, we systematically studied the surface nitrogen species of NCNs by varying the pyrolysis temperature, and found that the active pyridinic N‐oxide species formed in a high thermal‐annealing treatment, acting synergistically with vanadium active sites in converting ethyl lactate with oxygen into ethyl pyruvate under mild conditions.

show abstract

“…Consequently, recent research activities have been focused on developing effective bifunctional catalysts with greater performance and cost-effectiveness, and superior durability, for both the ORR and the OER, for widespread applications. Oxides and hydroxides based on transition metals, such as nickel, cobalt, iron, molybdenum, titanium, and tungsten, have emerged as a promising class of noble metal-free material catalysts [12][13][14]. These earth-abundant materials on various supports have been identified as high activity and stability electrocatalysts for the OER and the ORR under neutral or strongly alkaline conditions [15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Bifunctional Electrocatalyst of Low-Symmetry Mesoporous Titanium Dioxide Modified with Cobalt Oxide for Oxygen Evolution and Reduction Reactions

et al. 2019

View full text Add to dashboard Cite

Hybrids of low-symmetry (disordered) mesoporous titanium dioxide modified with different weight ratios of cobalt oxide nanoparticles (Co3O4(x)/lsm-TiO2) are prepared using a one-pot self-assembly surfactant template. The physicochemical characterization of Co3O4(x)/lsm-TiO2 hybrids by scanning and transmission electron microscopy, X-ray diffraction, N2 adsorption–desorption isotherms, and X-ray photoelectron spectroscopy confirm the successful incorporation of cobalt oxide nanoparticles (2–3 nm in diameter) with preservation of the highly mesoporous structure of titanium dioxide substrate. Among these mesoporous hybrids, the ~3.0 wt.% Co3O4/lsm-TiO2 exhibits the best performance toward both the oxygen evolution (OER) and reduction (ORR) reactions in alkaline solution. For the OER, the hybrid shows oxidation overpotential of 348 mV at 10 mA cm−2, a turnover frequency (TOF) of 0.034 s−1, a Tafel slope of 54 mV dec−1, and mass activity of 42.0 A g−1 at 370 mV. While for ORR, an onset potential of 0.84 V vs. RHE and OER/ORR overpotential gap (ΔE) of 0.92 V are achieved which is significantly lower than that of commercial Pt/C, hexagonal mesoporous, and bulk titanium dioxide analogous. The Co3O4/lsm-TiO2 hybrid demonstrates significantly higher long-term durability than IrO2. Apparently, such catalytic activity performance originates from the synergetic effect between Co3O4 and TiO2 substrate, in addition to higher charge carrier density and the presence of disordered mesopores which provide short ions diffusion path during the electrocatalytic process.

show abstract

Understanding the oxidative dehydrogenation of ethyl lactate to ethyl pyruvate over vanadia/titania

Abstract: We studied the vapour-phase oxidative dehydrogenation of ethyl lactate to ethyl pyruvate over V2O5/TiO2 catalysts in a fixed-bed reactor.

Cited by 32 publications

References 66 publications

Self-Exfoliated Synthesis of Transition Metal Phosphate Nanolayers for Selective Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate

Self-Exfoliated Synthesis of Transition Metal Phosphate Nanolayers for Selective Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate

Selective Aerobic Oxidation of Lactate to Pyruvate Catalyzed by Vanadium‐Nitrogen‐Doped Carbon Nanosheets

Bifunctional Electrocatalyst of Low-Symmetry Mesoporous Titanium Dioxide Modified with Cobalt Oxide for Oxygen Evolution and Reduction Reactions

Contact Info

Product

Resources

About