Restructuring highly electron-deficient metal-metal oxides for boosting stability in acidic oxygen evolution reaction

AbstractThe poor catalyst stability in acidic oxidation evolution reaction (OER) has been a long-time issue. Herein, we introduce electron-deficient metal on semiconducting metal oxides-consisting of Ir (Rh, Au, Ru)-MoO3 embedded by graphitic carbon layers (IMO) using an electrospinning method. We systematically investigate IMO’s structure, electron transfer behaviors, and OER catalytic performance by combining experimental and theoretical studies. Remarkably, IMO with an electron-deficient metal surface (Irx+; x > 4) exhibit a low overpotential of only ~156 mV at 10 mA cm−2 and excellent durability in acidic media due to the high oxidation state of metal on MoO3. Furthermore, the proton dissociation pathway is suggested via surface oxygen serving as proton acceptors. This study suggests high stability with high catalytic performance in these materials by creating electron-deficient surfaces and provides a general, unique strategy for guiding the design of other metal-semiconductor nanocatalysts.

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Effect of Small Molecular Organic Acids on the Structure and Catalytic Performance of Sol–Gel Prepared Cobalt Cerium Oxides towards Toluene Combustion

Catalysts ◽

10.3390/catal9050483 ◽

2019 ◽

Vol 9 (5) ◽

pp. 483 ◽

Cited By ~ 2

Author(s):

Jianmeng Chen ◽

Junhong Lin ◽

Jinghuan Chen ◽

Jiade Wang

Keyword(s):

Catalytic Activity ◽

Organic Acids ◽

Metal Oxides ◽

Sol Gel ◽

Catalytic Performance ◽

Time Activity ◽

Cerium Oxides ◽

Structure Morphology ◽

Long Time ◽

Composition Structure

Cobalt cerium oxide catalysts with small molecular organic acids (SOAs) as chelating agents were prepared via the sol–gel method and investigated for the complete oxidation of toluene. Four kinds of natural SOAs, i.e. malic acid (MA), citric acid (CA), glycolic acid (GA), and tartaric acid (TA), were selected. The effect of organic acids on the composition, structure, morphology and catalytic performance of metal oxides is discussed in details. The cobalt cerium oxides catalysts were characterized by various techniques, including TG–DSC, XRD, SEM–EDS, N2–adsorption and desorption, XPS, and H2–TPR analyses. The results show that the nature of organic acids influenced the hydrolysis, condensation and calcination processes, as well as strongly affected the textural and physicochemical properties of the metal oxides synthesized. The best catalytic activity was obtained with the CoCe–MA catalyst, and the toluene conversion reached 90% at 242 °C. This outstanding catalytic activity could be related to its textural, redox properties and unique surface compositions and oxidation states. In addition, the CoCe–MA catalyst also showed excellent stability in long–time activity test.

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Catalytic Performance of Metal Oxides Promoted Nickel Catalysts Supported on Mesoporous γ-Alumina in Dry Reforming of Methane

Processes ◽

10.3390/pr8050522 ◽

2020 ◽

Vol 8 (5) ◽

pp. 522

Author(s):

Anis H. Fakeeha ◽

Abdulaziz A. Bagabas ◽

Mahmud S. Lanre ◽

Ahmed I. Osman ◽

Samsudeen O. Kasim ◽

...

Keyword(s):

Metal Oxides ◽

Nickel Catalysts ◽

Catalytic Performance ◽

Dry Reforming ◽

Coke Deposition ◽

Dry Reforming Of Methane ◽

Catalyst Stability ◽

Incipient Wetness Impregnation ◽

Impregnation Method ◽

Ni Catalysts

Dry reforming of CH4 was conducted over promoted Ni catalysts, supported on mesoporous gamma-alumina. The Ni catalysts were promoted by various metal oxides (CuO, ZnO, Ga2O3, or Gd2O3) and were synthesized by the incipient wetness impregnation method. The influence of the promoters on the catalyst stability, coke deposition, and H2/CO mole ratio was investigated. Stability tests were carried out for 460 min. The H2 yield was 87% over 5Ni+1Gd/Al, while the CH4 and CO2 conversions were found to decrease in the following order: 5Ni+1Gd/Al > 5Ni+1Ga/Al > 5Ni+1Zn/Al > 5Ni/Al > 5Ni+1Cu/Al. The high catalytic performance of 5Ni+1Gd/Al, 5Ni+1Ga/Al, and 5Ni+1Zn/Al was found to be closely related to their contents of NiO species, which interacted moderately and strongly with the support, whereas free NiO in 5Ni+1Cu/Al made it catalytically inactive, even than 5Ni/Al. The 5Ni+1Gd/Al catalyst showed the highest CH4 conversion of 83% with H2/CO mole ratio of ~1.0.

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Carbon Monoxide Sensing Technologies

10.21741/9781644901212 ◽

2021 ◽

Keyword(s):

Thin Films ◽

Carbon Nanotubes ◽

Carbon Monoxide ◽

Metal Oxides ◽

Electrochemical Sensors ◽

Colorimetric Detection ◽

Infrared Sensors ◽

Polymeric Thin Films ◽

Semiconducting Metal Oxides ◽

Book Covers

The book covers the sensing and monitoring of poisonous carbon monoxide pollution in the environment. The sensors covered include semiconducting metal oxides, carbon nanotubes, conducting polymeric thin films, sensors based on colorimetric detection, non-dispersive infrared sensors, electrochemical sensors and photoacoustic detectors.

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A direct solvent-free conversion approach to prepare mixed-metal metal–organic frameworks from doped metal oxides

Chemical Communications ◽

10.1039/d1cc00671a ◽

2021 ◽

Vol 57 (29) ◽

pp. 3587-3590

Author(s):

Beili Yi ◽

Haojie Zhao ◽

Yue Zhang ◽

Xiaomeng Si ◽

Guanqun Zhang ◽

...

Keyword(s):

Metal Oxides ◽

Metal Organic Frameworks ◽

Solvent Free ◽

Mixed Metal ◽

Synthesis Strategy ◽

Metal Metal ◽

Metal Organic

We propose a novel solvent-free conversion strategy of Pt–ZnO to Pt-ZIF-8. This synthesis strategy may facilitate the discovery of MMOFs that have not been reported previously.

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Metal, Metal Oxides and Metal Sulphides for Biomedical Applications

10.1007/978-3-030-56413-1 ◽

2021 ◽

Keyword(s):

Metal Oxides ◽

Biomedical Applications ◽

Metal Metal

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Ni-Fe-Co based mixed metal/metal-oxides nanoparticles encapsulated in ultrathin carbon nanosheets: A bifunctional electrocatalyst for overall water splitting

Surfaces and Interfaces ◽

10.1016/j.surfin.2021.101361 ◽

2021 ◽

pp. 101361

Author(s):

Waleed Yaseen ◽

Nabi Ullah ◽

Meng Xie ◽

Bashir Adegbemiga Yusuf ◽

Yuanguo Xu ◽

...

Keyword(s):

Metal Oxides ◽

Water Splitting ◽

Carbon Nanosheets ◽

Mixed Metal ◽

Bifunctional Electrocatalyst ◽

Overall Water Splitting ◽

Metal Metal

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Metal-Organic Frameworks in Oxidation Catalysis with Hydrogen Peroxide

Catalysts ◽

10.3390/catal11020283 ◽

2021 ◽

Vol 11 (2) ◽

pp. 283

Author(s):

Oxana Kholdeeva ◽

Nataliya Maksimchuk

Keyword(s):

Hydrogen Peroxide ◽

Liquid Phase ◽

Selective Oxidation ◽

Metal Organic Frameworks ◽

Short Review ◽

Catalytic Performance ◽

Oxidation Catalysis ◽

Catalyst Stability ◽

Aqueous Hydrogen Peroxide ◽

Metal Organic

In recent years, metal–organic frameworks (MOFs) have received increasing attention as selective oxidation catalysts and supports for their construction. In this short review paper, we survey recent findings concerning use of MOFs in heterogeneous liquid-phase selective oxidation catalysis with the green oxidant–aqueous hydrogen peroxide. MOFs having outstanding thermal and chemical stability, such as Cr(III)-based MIL-101, Ti(IV)-based MIL-125, Zr(IV)-based UiO-66(67), Zn(II)-based ZIF-8, and some others, will be in the main focus of this work. The effects of the metal nature and MOF structure on catalytic activity and oxidation selectivity are analyzed and the mechanisms of hydrogen peroxide activation are discussed. In some cases, we also make an attempt to analyze relationships between liquid-phase adsorption properties of MOFs and peculiarities of their catalytic performance. Attempts of using MOFs as supports for construction of single-site catalysts through their modification with heterometals will be also addressed in relation to the use of such catalysts for activation of H2O2. Special attention is given to the critical issues of catalyst stability and reusability. The scope and limitations of MOF catalysts in H2O2-based selective oxidation are discussed.

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Performance Analysis of TiO2-Modified Co/MgAl2O4 Catalyst for Dry Reforming of Methane in a Fixed Bed Reactor for Syngas (H2, CO) Production

Energies ◽

10.3390/en14113347 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3347

Author(s):

Arslan Mazhar ◽

Asif Hussain Khoja ◽

Abul Kalam Azad ◽

Faisal Mushtaq ◽

Salman Raza Naqvi ◽

...

Keyword(s):

Catalytic Activity ◽

Fixed Bed ◽

Catalytic Performance ◽

Dry Reforming ◽

Fixed Bed Reactor ◽

Dry Reforming Of Methane ◽

Catalyst Stability ◽

Feed Ratio ◽

Catalyst Loading ◽

Impregnation Method

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process.

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