Room temperature selective conversion of aniline to azoxybenzene over an amorphous niobium oxyhydroxide supported on δ-FeOOH

Lima, André L. D.; Batalha, Daniel Carreira; Fajardo, Humberto V.; Rodrigues, Jairo Lisboa; Pereira, Márcio C.; Silva, Adilson C.

doi:10.1016/j.cattod.2018.10.035

Cited by 30 publications

(13 citation statements)

References 38 publications

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“…The bands at 1446 and 1539 cm –1 have been used for the quantification of acid sites, which showed that mNb-bc had acidity, with a total amount of acid sites of 65 μmol g –1 . In fact, this high acidity value can promote a conversion of substrates without extensive formation of byproducts, as it was reported for catalysts with high acidity …”

Section: Results and Discussionmentioning

confidence: 52%

“…In fact, this high acidity value can promote a conversion of substrates without extensive formation of byproducts, as it was reported for catalysts with high acidity. 18 …”

Section: Results and Discussionmentioning

confidence: 99%

“…In fact, this high acidity value can promote a conversion of substrates without extensive formation of byproducts, as it was reported for catalysts with high acidity. 18 The diffractogram of mNb-bc is shown in Figure 2. The synthesis of mNb-bc was not carried out at high temperatures, and the mNb-bc did not undergo a hydrothermal or a thermal treatment process before the catalytic tests.…”

Section: Resultsmentioning

confidence: 99%

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New Approach to Dehydration of Xylose to 2-Furfuraldehyde Using a Mesoporous Niobium-Based Catalyst

et al. 2020

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Furfural chemistry is one of the most promising platforms directly derived from lignocellulose biomass. In this study, a niobium-based catalyst (mNb-bc) was synthesized by a new fast and simple method. This new method uses microemulsion to obtain a catalyst with a high specific surface area (340 m 2 g –1 ), defined mesoporosity, and high acidity (65 μmol g –1 ). Scanning electron microscopy revealed that mNb-bc has a rough surface. The mNb-bc was used to catalyze the conversion reaction of xylose into 2-furfuraldehyde in a monophasic system using water as a green solvent. This reaction was investigated using a 2 3 experimental design by varying the temperature, time, and catalyst-to-xylose ratio (CXR). The responses evaluated were xylose conversion ( X c ), reaction yield ( Y ), and selectivity to 2-furfuraldehyde ( S ). The optimized reaction conditions were used to evaluate the reaction kinetics. At milder reaction conditions of 140 °C, 2 h, and a CXR of 10%, mNb-bc led to an X c value of 41.2%, an S value of 77.1%, and a Y value of 31.8%.

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Section: Results and Discussionmentioning

confidence: 52%

“…In fact, this high acidity value can promote a conversion of substrates without extensive formation of byproducts, as it was reported for catalysts with high acidity. 18 …”

Section: Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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New Approach to Dehydration of Xylose to 2-Furfuraldehyde Using a Mesoporous Niobium-Based Catalyst

et al. 2020

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“…Iron oxyhydroxides are one series of iron mineral widely presented in nature, most of which are wide bandgap (> 2 eV) semiconductors or insulators. It is reported that there are several types of stable phases, namely goethite (α-FeOOH) 43,44 , akaganeite (β-FeOOH) 45 and lepidocrocite (γ-FeOOH) [46][47][48][49][50][51][52] . These crystal structures are shown in Fig.…”

Section: Iron Oxyhydroxidesmentioning

confidence: 99%

Development of Iron-Based Heterogeneous Cocatalysts for Photoelectrochemical Water Oxidation

Li¹,

Hu²,

Huang³

et al. 2020

Acta Physico Chimica Sinica

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The use of fossil fuels has caused serious environmental problems such as air pollution and the greenhouse effect. Moreover, because fossil fuels are a non-renewable energy source, they cannot meet the continuously increasing demand for energy. Therefore, the development of clean and renewable energy sources is necessitated. Hydrogen energy is a clean, non-polluting renewable energy source that can ease the energy pressure of the whole society. The sunlight received by the Earth is 1.7 × 10 14 J in 1 s, which far exceeds the total energy consumption of humans in one year. Therefore, conversion of solar energy to valuable hydrogen energy is of significance for reducing the dependence on fossil fuels. Since Fujishima and Honda first reported on TiO2 in 1972, it has been discovered that semiconductors can generate clean, pollution-free hydrogen through water splitting driven by electricity or light. Hydrogen generated through this approach can not only replace fossil fuels but also provide environmentally friendly renewable hydrogen energy, which has attracted considerable attention. Photoelectrochemical (PEC) water splitting can use solar energy to produce clean, sustainable hydrogen energy. Because the oxygen evolution reaction (OER) over a photoanode is sluggish, the overall energy conversion efficiency is considerably low, limiting the practical application of PEC water splitting. A cocatalyst is, thus, necessary to improve PEC water splitting performance. So far, the synthesis of first-row transition-metal-based (e.g., Fe, Co, Ni, and Mn) cocatalysts has been intensively studied. Iron is earth-abundant and less toxic than other transition metals, making it a good cocatalyst. In addition, iron-based compounds exhibit the properties of a semiconductor/metal and have unique electronic structures, which can improve electrical conductivity and water adsorption. Various iron-based catalysts with high activity have been designed to improve the efficiency of PEC water oxidation. This article briefly summarizes the research progress related to the structure, synthesis, and application of iron oxyhydroxides, iron-based layered double hydroxides, and iron-based perovskites and discusses the evaluation of the performance of these cocatalysts toward photoelectrochemical water oxidation.

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“…NbOOH supported on FeOOH was reported to reach full aniline conversion with 70% azoxybenzene selectivity after 25 h at RT, though this required a relatively high R c/s of 0.1 (see Table S1 †). 47 A Nb-Zn-Al-oxide catalyst (∼4 wt% Nb loading, R c/s = 0.1) was reported to reach 92% azoxybenzene yield in the presence of UV irradiation for 48 h, whereas the yield dropped to 0% without irradiation. 48 The initial test with Nb 2 O 5 -scCO 2 as a heterogeneous catalyst for the oxidation of aniline to azoxybenzene with aqueous H 2 O 2 as the oxidant was carried out without external heating and with a low catalyst loading (R c/s = 0.005) compared to the values generally employed in the literature (Table S1 †).…”

Section: Catalytic Experimentsmentioning

confidence: 99%

Niobium oxide prepared through a novel supercritical-CO₂-assisted method as a highly active heterogeneous catalyst for the synthesis of azoxybenzene from aniline

et al. 2019

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Room temperature selective conversion of aniline to azoxybenzene over an amorphous niobium oxyhydroxide supported on δ-FeOOH

Cited by 30 publications

References 38 publications

New Approach to Dehydration of Xylose to 2-Furfuraldehyde Using a Mesoporous Niobium-Based Catalyst

New Approach to Dehydration of Xylose to 2-Furfuraldehyde Using a Mesoporous Niobium-Based Catalyst

Development of Iron-Based Heterogeneous Cocatalysts for Photoelectrochemical Water Oxidation

Niobium oxide prepared through a novel supercritical-CO₂-assisted method as a highly active heterogeneous catalyst for the synthesis of azoxybenzene from aniline

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Room temperature selective conversion of aniline to azoxybenzene over an amorphous niobium oxyhydroxide supported on δ-FeOOH

Cited by 30 publications

References 38 publications

New Approach to Dehydration of Xylose to 2-Furfuraldehyde Using a Mesoporous Niobium-Based Catalyst

New Approach to Dehydration of Xylose to 2-Furfuraldehyde Using a Mesoporous Niobium-Based Catalyst

Development of Iron-Based Heterogeneous Cocatalysts for Photoelectrochemical Water Oxidation

Niobium oxide prepared through a novel supercritical-CO2-assisted method as a highly active heterogeneous catalyst for the synthesis of azoxybenzene from aniline

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Niobium oxide prepared through a novel supercritical-CO₂-assisted method as a highly active heterogeneous catalyst for the synthesis of azoxybenzene from aniline