<i>In situ</i> valence modification of Pd/NiO nano-catalysts in supercritical water towards toluene oxidation

Meng, Qingjie; Li, Jiajia; Weng, Xiaole; Sun, Ping; Darr, Jawwad A.; Wu, Zhongbiao

doi:10.1039/c7cy02366a

Cited by 39 publications

(10 citation statements)

References 51 publications

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“…The BEs at ca. 853.7 and 855.6 eV can be attributed to Ni 2+ and Ni 3+ species, 31 respectively (Figure 4B). In addition, the characteristic satellite peaks due to Ni 2+ species from the Ni 2p 3/2 core level can be well observed at ca.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Tailoring the Reactive Oxygen Species in Mesoporous NiO for Selectivity-Controlled Aerobic Oxidation of 5-Hydroxymethylfurfural on a Loaded Pt Catalyst

Zhang

Gao

Cao

et al. 2021

ACS Sustainable Chem. Eng.

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The base-free aerobic oxidation of 5-hydroxymethylfurfural (HMF) in water to 2,5-furandicarboxylic acid (FDCA) is a sustainable upgrading process for cellulosic carbohydrates. A mesoporous NiO-supported Pt nanoparticle (ca. 3 nm) catalyst was reported, which can achieve 100% selectivity to FDCA at a full conversion of HMF without the assistance of any base under mild conditions, that is, 100 °C, 10 bar O2, and 12 h. The catalyst efficiency in terms of productivity reached 22.2 molFDCA molPt –1 h–1, which is the highest value among all the supported Pt catalysts to date in literature. Moreover, the Pt/NiO catalyst showed a remarkably stable and reusable performance during five consecutive cycling. X-ray diffraction, N2 physisorption, transmission electron microscopy, X-ray photoelectron spectroscopy, CO-adsorbed diffuse reflectance Fourier transform infrared spectroscopy, temperature-programed reduction of hydrogen, temperature-programed desorption of oxygen, and electron paramagnetic resonance techniques were used to comprehensively analyze the catalysts. It was disclosed that tailoring the reactive oxygen species in NiO is an effective way to control the initial reaction rate of HMF as well as the derived intermediates (i.e., a reflection of product distribution). This can be manipulated by varying the aging temperature during the preparation of NiO; thus, the role of different oxygen species (i.e., Oads. and Olatt.) in NiO was clarified. The interaction between the metallic Pt active sites and the mobile oxygen species was found to be critical to the excellent catalytic performance.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Tailoring the Reactive Oxygen Species in Mesoporous NiO for Selectivity-Controlled Aerobic Oxidation of 5-Hydroxymethylfurfural on a Loaded Pt Catalyst

Zhang

Gao

Cao

et al. 2021

ACS Sustainable Chem. Eng.

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“…Typically, more Pt δ + content means more Pt–O bonds and a better dispersion of Pt atoms. 27 Detailed statistics are shown in Table 2 . As shown, the WI method and sphere morphology are beneficial for Pt dispersion, resulting in more Pt–O bonds ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Facial controlled synthesis of Pt/MnO₂ catalysts with high efficiency for VOCs combustion

Gao

Fan

et al. 2021

RSC Adv.

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“…Nanometal oxides produced in water from the oxidation experiments were allowed to settle for 24 h. A few drops of settled nanoparticles were then sampled and suspended in acetone for examination by TEM. The JEOL 2100F system (FEGTEM) was used for TEM images operating at an acceleration voltage of 100 kV (Meng et al 2018 ).…”

Section: Methodsmentioning

confidence: 99%

Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst

Al-Atta

Sher

Hazafa

et al. 2021

Environ Sci Pollut Res

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During the past few decades, the treatment of hazardous waste and toxic phenolic compounds has become a major issue in the pharmaceutical, gas/oil, dying, and chemical industries. Considering polymerization and oxidation of phenolic compounds, supercritical water oxidation (SCWO) has gained special attention. The present study objective was to synthesize a novel in situ Fe2O3nano-catalyst in a counter-current mixing reactor by supercritical water oxidation (SCWO) method to evaluate the phenol oxidation and COD reduction at different operation conditions like oxidant ratios and concentrations. Synthesized nano-catalyst was characterized by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). TEM results revealed the maximum average particle size of 26.18 and 16.20 nm for preheated and non-preheated oxidant configuration, respectively. XRD showed the clear peaks of hematite at a 2θ value of 24, 33, 35.5, 49.5, 54, 62, and 64 for both catalysts treated preheated and non-preheated oxidant configurations. The maximum COD reduction and phenol oxidation of about 93.5% and 99.9% were observed at an oxidant ratio of 1.5, 0.75 s, 25 MPa, and 380 °C with a non-preheated H2O2 oxidant, while in situ formed Fe2O3nano-catalyst showed the maximum phenol oxidation of 99.9% at 0.75 s, 1.5 oxidant ratio, 25 MPa, and 380 °C. Similarly, in situ formed Fe2O3 catalyst presented the highest COD reduction of 97.8% at 40 mM phenol concentration, 1.0 oxidant ratio, 0.75 s residence time, 380 °C, and 25 MPa. It is concluded and recommended that SCWO is a feasible and cost-effective alternative method for the destruction of contaminants in water which showed the complete conversion of phenol within less than 1 s and 1.5 oxidant ratio.

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In situ valence modification of Pd/NiO nano-catalysts in supercritical water towards toluene oxidation

Abstract: Pd0 is more active than PdOx in toluene oxidation owing to its capability of activating gaseous oxygen at low temperatures and returning to the original state even with excess O2.

Cited by 39 publications

References 51 publications

Tailoring the Reactive Oxygen Species in Mesoporous NiO for Selectivity-Controlled Aerobic Oxidation of 5-Hydroxymethylfurfural on a Loaded Pt Catalyst

Tailoring the Reactive Oxygen Species in Mesoporous NiO for Selectivity-Controlled Aerobic Oxidation of 5-Hydroxymethylfurfural on a Loaded Pt Catalyst

Facial controlled synthesis of Pt/MnO₂ catalysts with high efficiency for VOCs combustion

Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst

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In situ valence modification of Pd/NiO nano-catalysts in supercritical water towards toluene oxidation

Abstract: Pd0 is more active than PdOx in toluene oxidation owing to its capability of activating gaseous oxygen at low temperatures and returning to the original state even with excess O2.

Cited by 39 publications

References 51 publications

Tailoring the Reactive Oxygen Species in Mesoporous NiO for Selectivity-Controlled Aerobic Oxidation of 5-Hydroxymethylfurfural on a Loaded Pt Catalyst

Tailoring the Reactive Oxygen Species in Mesoporous NiO for Selectivity-Controlled Aerobic Oxidation of 5-Hydroxymethylfurfural on a Loaded Pt Catalyst

Facial controlled synthesis of Pt/MnO2 catalysts with high efficiency for VOCs combustion

Supercritical water oxidation of phenol and process enhancement with in situ formed Fe2O3 nano catalyst

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Facial controlled synthesis of Pt/MnO₂ catalysts with high efficiency for VOCs combustion