Oxygen vacancies confined in nickel oxide nanoprism arrays for promoted electrocatalytic water splitting

Experimental and DFT calculation results show that the presence of oxygen vacancies can decrease the adsorption energy of intermediates at active sites and facilitate their adsorption, thus improving the catalytic properties.

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Oxygen vacancy-confined CoMoO4@CoNiO2 nanorod arrays for oxygen evolution with improved performance

Dalton Transactions ◽

10.1039/c9dt01378d ◽

2019 ◽

Vol 48 (27) ◽

pp. 10116-10121 ◽

Cited By ~ 11

Author(s):

Xiaoqiang Du ◽

Guangyu Ma ◽

Xiaoshuang Zhang

Keyword(s):

Oxygen Vacancy ◽

Oxygen Evolution ◽

Adsorption Energy ◽

Active Sites ◽

Oxygen Vacancies ◽

Dft Calculation ◽

Catalytic Properties ◽

Nanorod Arrays ◽

Calculation Results ◽

Improved Performance

Experimental and DFT calculation results show that the presence of oxygen vacancies can decrease the adsorption energy of intermediates at active sites and facilitate the adsorption of intermediates, thus improving the catalytic properties.

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Ultrathin NiCo2O4 nanosheets with dual-metal active sites for enhanced solar water splitting of a BiVO4 photoanode

Journal of Materials Chemistry A ◽

10.1039/c9ta08951a ◽

2019 ◽

Vol 7 (39) ◽

pp. 22274-22278 ◽

Cited By ~ 10

Author(s):

Chenchen Feng ◽

Qi Zhou ◽

Bin Zheng ◽

Xiang Cheng ◽

Yajun Zhang ◽

...

Keyword(s):

Water Splitting ◽

Water Oxidation ◽

Active Sites ◽

Oxygen Vacancies ◽

Solar Water ◽

Solar Water Splitting ◽

Highly Efficient ◽

Dual Metal ◽

Nico2o4 Nanosheets ◽

First Time

Spinel-structured NiCo2O4 nanosheets with dual-metal active sites, an ultrathin structure, and abundant oxygen vacancies were decorated for the first time on a BiVO4 photoanode for highly efficient PEC water oxidation.

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Effect of Mo Dispersion on the Catalytic Properties and Stability of Mo–Fe Catalysts for the Partial Oxidation of Methanol

Molecules ◽

10.3390/molecules25102410 ◽

2020 ◽

Vol 25 (10) ◽

pp. 2410

Author(s):

Shuai Zhang ◽

Minghan Han

Keyword(s):

Surface Layer ◽

Surface Area ◽

Partial Oxidation ◽

Active Sites ◽

Oxygen Vacancies ◽

Catalyst Surface ◽

Catalytic Properties ◽

Oxidation Of Methanol ◽

Partial Oxidation Of Methanol ◽

Fe Catalysts

Mo–Fe catalysts with different Mo dispersions were synthesized with fast (Cat-FS, 600 r·min−1) or slow stirring speed (Cat-SS, 30 r·min−1) by the coprecipitation method. Improving the stirring speed strengthened the mixing of the solution and increased the dispersion of particles in the catalyst, which exhibited favorable activity and selectivity. The byproduct (dimethyl ether (DME)) selectivity increased from 2.3% to 2.8% with Cat-SS, while it remained unchanged with Cat-FS in a stability test. The aggregation of particles and thin Mo-enriched surface layer decreased the catalyst surface area and slowed down the reoxidation of reduced active sites with Cat-SS, leaving more oxygen vacancies which promoted the formation of DME by the nonoxidative channel.

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An Efficient Nickel Sulfide@NiO Nanocomposite Catalyst with High Density of Active Sites for the Hydrogen Evolution Reaction in Alkaline Media

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19094 ◽

2021 ◽

Vol 21 (4) ◽

pp. 2520-2528

Author(s):

Shams Parveen Khokhar ◽

Mazhar Ali Abbasi ◽

Umair Aftab ◽

Muhammad Ishaq Abro ◽

Aqeel Ahmed Shah ◽

...

Keyword(s):

Nickel Oxide ◽

Hydrogen Evolution ◽

Water Splitting ◽

Hydrogen Evolution Reaction ◽

Active Sites ◽

Alkaline Media ◽

Alkaline Electrolyte ◽

Oxide Content ◽

Onset Potential ◽

Composite Catalysts

Efficient hydrogen evolution reaction (HER) catalysts based on the earth-abundant materials are highly vital to design practical and environmentally friendly water splitting devices. In this study, we present an optimized strategy for the development of active catalysts for hydrogen evolution reaction HER. The composite catalysts are prepared with the nanosurface of NiO for the deposition of NiS by hydrothermal method. In alkaline electrolyte, the NiS/NiO nanocomposite has shown excellent catalytic HER properties at the low onset potential and small Tafel slope of 72 mVdec-1. A current density of 10 mA/cm2 is achieved by the nanocomposite obtained with 0.4 gram of NiO as nanosurface for the deposition of NiS (sample 4) at the cost of 429 mV versus RHE. The sample 4 carries more active sites that allow it to act as excellent HER catalyst. Based on this study, we conclude that increasing the nickel oxide content into composite sample facilitates the HER process. Additionally, a long term HER stability for 10 hours and good durability is also demonstrated by the sample 4. Our findings reveal that the optimization of nickel oxide content in the preparation of catalyst leads to the excellent HER activity for the design of practical water splitting devices and other related applications.

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Oxygen defect engineering in cobalt iron oxide nanosheets for promoted overall water splitting

Journal of Materials Chemistry A ◽

10.1039/c9ta06537g ◽

2019 ◽

Vol 7 (38) ◽

pp. 21704-21710 ◽

Cited By ~ 18

Author(s):

Chengying Guo ◽

Xuejing Liu ◽

Lingfeng Gao ◽

Xiaojing Ma ◽

Mingzhu Zhao ◽

...

Keyword(s):

Electron Transfer ◽

Water Splitting ◽

Active Sites ◽

Oxygen Vacancies ◽

Catalytic Performance ◽

Oxygen Defect ◽

Defect Engineering ◽

Transfer Property ◽

Cobalt Iron Oxide ◽

Cobalt Iron

Benefited from the optimized activity of active sites, adsorption energy and the proposed electron transfer property, the CoFe2O4 nanosheet with oxygen vacancies exhibited significantly enhanced water splitting catalytic performance.

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A novel ligand with –NH2 and –COOH-decorated Co/Fe-based oxide for an efficient overall water splitting: dual modulation roles of active sites and local electronic structure

Catalysis Science & Technology ◽

10.1039/d0cy01109f ◽

2020 ◽

Vol 10 (18) ◽

pp. 6266-6273

Author(s):

Yalan Zhang ◽

Zebin Yu ◽

Ronghua Jiang ◽

Jung Huang ◽

Yanping Hou ◽

...

Keyword(s):

Electronic Structure ◽

Water Splitting ◽

Energy Demand ◽

Active Sites ◽

Electrode Materials ◽

Global Energy ◽

Overall Water Splitting ◽

Local Electronic Structure ◽

Electrochemical Water Splitting

Excellent electrochemical water splitting with remarkable durability can provide a solution to satisfy the increasing global energy demand in which the electrode materials play an important role.

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Investigation of Some Characterizations of Black TiO\(_2\) Nanotubes Via Spectroscopic Methods

Communications in Physics ◽

10.15625/0868-3166/29/2/13762 ◽

2019 ◽

Vol 29 (2) ◽

pp. 189 ◽

Cited By ~ 1

Author(s):

Tho Truong Nguyen ◽

Thi Minh Cao ◽

Hieu Van Le ◽

Viet Van Pham

Keyword(s):

Water Splitting ◽

Oxygen Vacancies ◽

Light Response ◽

Nanotube Arrays ◽

Spectroscopic Methods ◽

Visible Light Response ◽

Uv Visible ◽

Visible Reflectance ◽

Splitting Effect ◽

Anodization Method

The black TiO\(_2\) with substantial Ti\(^3+\) and oxygen vacancies exhibit an excellent photoelectrochemical water-splitting performance due to the improved charge transport the extended visible light response. In this study, black TiO\(_2\) nanotube arrays synthesized by the anodization method, and then, they have been investigated some characterizations by spectroscopic methods such as UV-visible reflectance (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectrum. The results showed that some highlighted properties of the black TiO2 nanotube arrays and they could apply for water-splitting effect.

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A Pyridinic Fe-N4 Macrocycle Effectively Models the Active Sites in Fe/N-Doped Carbon Electrocatalysts

10.26434/chemrxiv.10008545.v2 ◽

2020 ◽

Author(s):

Travis Marshall-Roth ◽

Nicole J. Libretto ◽

Alexandra T. Wrobel ◽

Kevin Anderton ◽

Nathan D. Ricke ◽

...

Keyword(s):

Oxygen Reduction ◽

Active Sites ◽

Catalytic Properties ◽

Reduction Reaction ◽

Iron Phthalocyanine ◽

Electrochemical Studies ◽

Onset Potential ◽

Nitrogen Doped Carbon ◽

Iron Active Sites

Iron- and nitrogen-doped carbon (Fe-N-C) materials are leading candidates to replace platinum in fuel cells, but their active site structures are poorly understood. A leading postulate is that iron active sites in this class of materials exist in an Fe-N4 pyridinic ligation environment. Yet, molecular Fe-based catalysts for the oxygen reduction reaction (ORR) generally feature pyrrolic coordination and pyridinic Fe-N4 catalysts are, to the best of our knowledge, non-existent. We report the synthesis and characterization of a molecular pyridinic hexaazacyclophane macrocycle, (phen2N2)Fe, and compare its spectroscopic, electrochemical, and catalytic properties for oxygen reduction to a prototypical Fe-N-C material, as well as iron phthalocyanine, (Pc)Fe, and iron octaethylporphyrin, (OEP)Fe, prototypical pyrrolic iron macrocycles. N 1s XPS signatures for coordinated N atoms in (phen2N2)Fe are positively shifted relative to (Pc)Fe and (OEP)Fe, and overlay with those of Fe-N-C. Likewise, spectroscopic XAS signatures of (phen2N2)Fe are distinct from those of both (Pc)Fe and (OEP)Fe, and are remarkably similar to those of Fe-N-C with compressed Fe–N bond lengths of 1.97 Å in (phen2N2)Fe that are close to the average 1.94 Å length in Fe-N-C. Electrochemical studies establish that both (Pc)Fe and (phen2N2)Fe have relatively high Fe(III/II) potentials at ~0.6 V, ~300 mV positive of (OEP)Fe. The ORR onset potential is found to directly correlate with the Fe(III/II) potential leading to a ~300 mV positive shift in the onset of ORR for (Pc)Fe and (phen2N2)Fe relative to (OEP)Fe. Consequently, the ORR onset for (phen2N2)Fe and (Pc)Fe is within 150 mV of Fe-N-C. Unlike (OEP)Fe and (Pc)Fe, (phen2N2)Fe displays excellent selectivity for 4-electron ORR with <4% maximum H2O2 production, comparable to Fe-N-C materials. The aggregate spectroscopic and electrochemical data establish (phen2N2)Fe as a pyridinic iron macrocycle that effectively models Fe-N-C active sites, thereby providing a rich molecular platform for understanding this important class of catalytic materials.

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Decomposition of hydrogen peroxide on a two-component NiO-CdO catalyst and the effect of ionizing radiation on its catalytic properties

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19791015 ◽

1979 ◽

Vol 44 (4) ◽

pp. 1015-1022 ◽

Cited By ~ 7

Author(s):

Viliam Múčka

Keyword(s):

Aqueous Solution ◽

Hydrogen Peroxide ◽

Catalytic Activity ◽

Nickel Oxide ◽

Catalytic Properties ◽

Cadmium Oxide ◽

Chemisorb Oxygen ◽

Composition Region ◽

Chemisorbed Oxygen ◽

Two Component

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.

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