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Publications (10 of 12) Show all publications
Tahira, A., Ibupoto, Z., Montecchi, M., Pasquali, L., Tonezzer, M., Nafady, A., . . . Vomiero, A. (2022). Role of cobalt precursors in the synthesis of Co 3 O 4 hierarchical nanostructures toward the development of cobalt‐based functional electrocatalysts for bifunctional water splitting in alkaline and acidic media. Journal of the Chinese Chemical Society (Taipei), 69(4), 681-691
Open this publication in new window or tab >>Role of cobalt precursors in the synthesis of Co 3 O 4 hierarchical nanostructures toward the development of cobalt‐based functional electrocatalysts for bifunctional water splitting in alkaline and acidic media
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2022 (English)In: Journal of the Chinese Chemical Society (Taipei), ISSN 0009-4536, E-ISSN 2192-6549, Vol. 69, no 4, p. 681-691Article in journal (Refereed) Published
Abstract [en]

The precursors have significant influence on the catalytic activity of nonprecious electrocatalysts for effective water splitting. Herein, we report active electrocatalysts based on cobalt oxide (Co3O4) hierarchical nanostructures derived from four different precursors of cobalt (acetate, nitrate, chloride, and sulfate salts) using the low-temperature aqueous chemical growth method. It has been found that the effect of precursor on the morphology of nanostructured material depends on the synthetic method. The Co3O4 nanostructures exhibited cubic phase derived from these four precursors. The Co3O4 nanostructures obtained from chloride precursor have demonstrated improved oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) compared to other precursors due relatively higher content of Co3O4 nanostructures at the surface of material. An overpotential of 400 mV versus reversible hydrogen electrode (RHE) at 10 mA cm−2 was observed for HER. The Co3O4 nanostructures derived from the chloride precursor have shown favorable reaction kinetics via 34 mV dec−1 value of the Tafel slope for HER reaction. The Co3O4 nanostructures derived from chloride precursor have also shown an excellent HER durability for 15 hr in alkaline media. Furthermore, the OER functional characterization was carried out onto Co3O4 nanostructures derived from chloride precursor exhibited 220 mV overpotential at 10 mA cm−2 and Tafel slope of 56 mV dec−1. Importantly, the reason behind the favorable catalytic activity of Co3O4 nanostructures derived from chloride precursor was linked to one order of magnitude smaller charge transfer resistance and higher amount of Co3O4 content at the surface of nanostructures than the Co3O4 nanostructures derived from other precursors. The performance of Co3O4 nanostructures derived from chloride precursor via the wet chemical method suggests that cobalt chloride precursor could be of great interest for the development of efficient, stable, nonprecious, and environmentally friendly electrocatalysts for the chemical energy conversion and storage devices.

Place, publisher, year, edition, pages
John Wiley & Sons, 2022
National Category
Materials Chemistry
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-90259 (URN)10.1002/jccs.202200012 (DOI)000779361600001 ()2-s2.0-85127682676 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-05-31 (johcin);

Funder: King Saud University (grant no. RSP-2022/79)

Available from: 2022-04-19 Created: 2022-04-19 Last updated: 2022-05-31Bibliographically approved
Tahira, A., Mazzaro, R., Rigoni, F., Nafady, A., Shaikh, S. F., Alothman, A. A., . . . Ibupoto, Z. H. (2021). A simple and efficient visible light photodetector based on Co3O4/ZnO composite. Optical and quantum electronics, 53(9), Article ID 534.
Open this publication in new window or tab >>A simple and efficient visible light photodetector based on Co3O4/ZnO composite
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2021 (English)In: Optical and quantum electronics, ISSN 0306-8919, E-ISSN 1572-817X, Vol. 53, no 9, article id 534Article in journal (Refereed) Published
Abstract [en]

Herein, we propose for the first time visible light photodetector based on n-type ZnO nanorods decorated with p-type Co3O4 nanowires. The heterojunction was fabricated on fluorine doped tin oxide (FTO) glass substrate by low temperature aqueous chemical growth method. ZnO exhibits nanorod morphology and cobalt oxide possesses nanowire shape with sharp tail. Energy dispersive spectroscopy confirmed the presence of Zn, O, and Co elements in the heterojunction. ZnO and Co3O4 have hexagonal and cubic phases, respectively, as confirmed by XRD. The dense and perpendicular ZnO nanorods are acting as a scattering layer for visible light, while Co3O4 nanowires act as a visible-light absorber. The all oxide p–n junction can operate as visible light photodetector. Furthermore, the heterojunction also shows a reproducible and fast response for the detection of visible light. Optimization of the device is needed (presence of buffer layers, tuning a thickness of the optical absorber) to improve its functionalities. 

Place, publisher, year, edition, pages
Springer Nature, 2021
Keywords
ZnO nanorods, Co3O4 nanosheets, Heterojunction, Visible light photodetector
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-86982 (URN)10.1007/s11082-021-03129-x (DOI)000690987400001 ()2-s2.0-85113418254 (Scopus ID)
Note

Validerad;2021;Nivå 2;2021-09-07 (alebob);

Forskningsfinansiär: King Saud University (RSP-2021/79)

Available from: 2021-09-06 Created: 2021-09-06 Last updated: 2021-09-07Bibliographically approved
Kumar, R., Qadir, G., Rajar, K., Balouch, A., Ibupoto, Z. H. & Parkash, A. (2021). Voltammetric detection of caffeine content in different tea stuffs by using Co3O4/GCE-Nafion electrode. Journal of the Iranian Chemical Society, 18(3), 701-708
Open this publication in new window or tab >>Voltammetric detection of caffeine content in different tea stuffs by using Co3O4/GCE-Nafion electrode
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2021 (English)In: Journal of the Iranian Chemical Society, ISSN 1735-207X, E-ISSN 1735-2428, Vol. 18, no 3, p. 701-708Article in journal (Refereed) Published
Abstract [en]

In this study, we synthesized Caffeine assisted Co3O4 nanostructures via a low-temperature hydrothermal method. After structural and surface characterization, prepared Co3O4 nanostructures were deposited on the surface of GCE through the drop-casting process with resulting electrode represented as Co3O4/GCE-Nafion. The modified electrode was used as a working electrode for oxidation of Caffeine (CAF). A square wave voltammetry technique used to examine the performance of the modified electrode offers the limit of detection (0.23 µM). In comparison, amperometry shows more sensitive responses such as the limit of detection (0.097 µM) and demonstrates good agreement in results at a wide range scale. The modified electrode exhibits good reproducibility with no significant interference in results. We compared these analytical results with other reported analytical techniques, but we obtain better results as compared to previous reports. Furthermore, Co3O4/GCE-Nafion was used to determine the concentration of CAF in tea samples, and the excellent recoveries were obtained at different concentrations of CAF. These results offer good reusability of the modified electrode in real-sample analysis and suggest the electrode feasibility for quality assurance of food and drug regularity authority applications.

Place, publisher, year, edition, pages
Springer, 2021
Keywords
Co3O4 NSs, Caffeine, Electrochemical Sensor, Food analysis
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-80940 (URN)10.1007/s13738-020-02059-x (DOI)000568639500001 ()2-s2.0-85090948954 (Scopus ID)
Note

Validerad;2021;Nivå 2;2021-02-18 (alebob)

Available from: 2020-09-28 Created: 2020-09-28 Last updated: 2021-02-18Bibliographically approved
Amin, S., Tahira, A., Solangi, A. R., Mazzaro, R., Ibupoto, Z. H., Fatima, A. & Vomiero, A. (2020). Functional Nickel Oxide Nanostructures for Ethanol Oxidation in Alkaline Media. Electroanalysis, 32(5), 1052-1059
Open this publication in new window or tab >>Functional Nickel Oxide Nanostructures for Ethanol Oxidation in Alkaline Media
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2020 (English)In: Electroanalysis, ISSN 1040-0397, E-ISSN 1521-4109, Vol. 32, no 5, p. 1052-1059Article in journal (Refereed) Published
Abstract [en]

Nickel oxide (NiO) nanostructures are employed in the basic medium for the oxidation of ethanol. A variety of NiO nanostructures are synthesized by wet chemical growth method, using different hydroxide (OH−) ion sources, particularly from ammonia, hexamethylenetetramine, urea and sodium hydroxide. The use of urea as (OH−) ion source results in flower‐like NiO structures composed by extremely thin nanowalls (thickness lower than 10 nm,), which demonstrated to be the most active for ethanol oxidation. All the samples exhibit NiO cubic phase, and no other impurity was detected. The cyclic voltammetry (CV) curves of NiO nanostructures were found linear over the concentration range 0.1–3.5 mM (R2=0.99) of ethanol, with the limit of detection estimated to be 0.013 mM for ethanol. The NiO nanostructures exhibit a selective signal towards ethanol oxidation in the presence of different members of alcohol family. The proposed NiO nanostructures showed a significant practicality for the reproducible and sensitive determination of ethanol from brandy, whisky, mixture of brandy and rum, and vodka samples. The nanomaterial was used as a surface modifying agent for the glassy carbon electrode and it showed a stable electro‐oxidation activity for the ethanol for 16 days. These findings indicate that the presented NiO nanomaterial can be applied in place of noble metals for ethanol sensing and other environmental applications (like fuel cells).

Place, publisher, year, edition, pages
John Wiley & Sons, 2020
Keywords
NiO nanostructures, (OH−) ion source, ethanol oxidation, alkaline media
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-77972 (URN)10.1002/elan.201900662 (DOI)000507436500001 ()2-s2.0-85078019459 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-05-26 (alebob)

Available from: 2020-03-05 Created: 2020-03-05 Last updated: 2022-10-27Bibliographically approved
Ibupoto, A., Qureshi, U., Arain, M., Ahmed, F., Khatri, Z., Brohi, R., . . . Ibupoto, Z. (2020). Zno/Carbon nanofibers for efficient adsorption of lead from aqueous solutions. Environmental technology, 41(21), 2731-2741
Open this publication in new window or tab >>Zno/Carbon nanofibers for efficient adsorption of lead from aqueous solutions
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2020 (English)In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 41, no 21, p. 2731-2741Article in journal (Refereed) Published
Abstract [en]

Hybrid nanofibers based on ZnO loaded activated carbon nanofibers (ZnO-ACNFs) are proposed here for the elimination of hazardous lead from aqueous solutions. The prepared ZnO nanoscale material was loaded into the polyacrylonitrile nanofibers (PAN NFs) which were later carbonized by using a novel method named as a plate-sandwich method. The Synthesized nanofibrous composite was characterized by SEM, TEM, EDX, FTIR and XRD techniques to analyze its chemical and morphological properties. Moreover, the nanocomposite was efficaciously applied for the lead (Pb2+) ions removal from wastewater and simulated water through continuous filtration and batch filtration. The ZnO-ACNFs membrane showed outstanding results in adsorptive removal, giving adsorption capacity of 92.59 mg/g within the contact time of 45 min. Compared to their counterparts (ZnO and CNFs), the hybrid ZnO-ACNFs showed excellent performance in removing toxic lead.

Place, publisher, year, edition, pages
Taylor & Francis, 2020
Keywords
Carbon, PAN, nanofibers, lead, water treatment
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-73074 (URN)10.1080/09593330.2019.1580774 (DOI)000561132300003 ()30734649 (PubMedID)2-s2.0-85089689911 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-08-31 (johcin)

Available from: 2019-03-01 Created: 2019-03-01 Last updated: 2022-10-27Bibliographically approved
Amin, S., Tahira, A., Solangi, A., Beni, V., Morante, J., Liu, X., . . . Vomiero, A. (2019). A practical non-enzymatic urea sensor based on NiCo2O4 nanoneedles. RSC Advances, 9(25), 14443-14451
Open this publication in new window or tab >>A practical non-enzymatic urea sensor based on NiCo2O4 nanoneedles
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2019 (English)In: RSC Advances, E-ISSN 2046-2069, Vol. 9, no 25, p. 14443-14451Article in journal (Refereed) Published
Abstract [en]

We propose a new facile electrochemical sensing platform for determination of urea, based on a glassy carbon electrode (GCE) modified with nickel cobalt oxide (NiCo2O4) nanoneedles. These nanoneedles are used for the first time for highly sensitive determination of urea with the lowest detection limit (1 μM) ever reported for the non-enzymatic approach. The nanoneedles were grown through a simple and low-temperature aqueous chemical method. We characterized the structural and morphological properties of the NiCo2O4 nanoneedles by TEM, SEM, XPS and XRD. The bimetallic nickel cobalt oxide exhibits nanoneedle morphology, which results from the self-assembly of nanoparticles. The NiCo2O4 nanoneedles are exclusively composed of Ni, Co, and O and exhibit a cubic crystalline phase. Cyclic voltammetry was used to study the enhanced electrochemical properties of a NiCo2O4 nanoneedle-modified GCE by overcoming the typical poor conductivity of bare NiO and Co3O4. The GCE-modified electrode is highly sensitive towards urea, with a linear response (R2 = 0.99) over the concentration range 0.01–5 mM and with a detection limit of 1.0 μM. The proposed non-enzymatic urea sensor is highly selective even in the presence of common interferents such as glucose, uric acid, and ascorbic acid. This new urea sensor has good viability for urea analysis in urine samples and can represent a significant advancement in the field, owing to the simple and cost-effective fabrication of electrodes, which can be used as a promising analytical tool for urea estimation.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-74362 (URN)10.1039/C9RA00909D (DOI)000468640100054 ()2-s2.0-85065663040 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-06-11 (johcin)

Available from: 2019-06-11 Created: 2019-06-11 Last updated: 2022-10-27Bibliographically approved
Amin, S., Tahira, A., Solangi, A., Mazzaro, R., Ibupoto, Z. & Vomiero, A. (2019). A sensitive enzyme-free lactic acid sensor based on NiO nanoparticles for practical applications. Analytical Methods, 11, 3578-3583
Open this publication in new window or tab >>A sensitive enzyme-free lactic acid sensor based on NiO nanoparticles for practical applications
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2019 (English)In: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 11, p. 3578-3583Article in journal (Refereed) Published
Abstract [en]

A facile and efficient electrochemical sensing platform has been successfully exploited for the first time for the determination of lactic acid using a nickel oxide (NiO) nanoparticle-modified glassy carbon electrode (GCE). Nickel oxide nanoparticles were prepared by a chemical growth method using different quantities of arginine as a soft template. The structural and morphological properties of NiO nanoparticles were characterized by Raman spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Cyclic voltammetry (CV) was used to study the electrochemical properties of various samples. The modified electrode is highly sensitive and presents a linear response over a wide range (0.005–5 mM) of lactic acid concentrations in 0.1 M NaOH. The detection limit for the sensor was found to be 5.7 μM, and it exhibits good stability. Furthermore, the sensor shows excellent selectivity in the presence of common interfering species. The lactic acid sensor showed good viability for lactic acid analysis in real samples (milk, yogurt and red wine) and demonstrated significant advancement in sensor technology for practical applications.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-75559 (URN)10.1039/C9AY00516A (DOI)000475986600010 ()2-s2.0-85069500109 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-16 (johcin)

Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2022-10-27Bibliographically approved
Tahira, A., Ibupoto, Z., Mazzaro, R., You, S., Morandi, V., Natile, M. M., . . . Vomiero, A. (2019). Advanced Electrocatalysts for Hydrogen Evolution Reaction Based on Core–Shell MoS2/TiO2 Nanostructures in Acidic and Alkaline Media. ACS Applied Energy Materials, 2(3), 2053-2062
Open this publication in new window or tab >>Advanced Electrocatalysts for Hydrogen Evolution Reaction Based on Core–Shell MoS2/TiO2 Nanostructures in Acidic and Alkaline Media
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2019 (English)In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 2, no 3, p. 2053-2062Article in journal (Refereed) Published
Abstract [en]

Hydrogen production as alternative energy source is still a challenge due to the lack of efficient and inexpensive catalysts, alternative to platinum. Thus, stable, earth abundant, and inexpensive catalysts are of prime need for hydrogen production via hydrogen evolution reaction (HER). Herein, we present an efficient and stable electrocatalyst composed of earth abundant TiO2 nanorods decorated with molybdenum disulfide thin nanosheets, a few nanometers thick. We grew rutile TiO2 nanorods via the hydrothermal method on conducting glass substrate, and then we nucleated the molybdenum disulfide nanosheets as the top layer. This composite possesses excellent hydrogen evolution activity in both acidic and alkaline media at considerably low overpotentials (350 mV and 700 mV in acidic and alkaline media, respectively) and small Tafel slopes (48 and 60 mV/dec in acidic and alkaline conditions, respectively), which are better than several transition metal dichalcogenides, such as pure molybdenum disulfide and cobalt diselenide. A good stability in acidic and alkaline media is reported here for the new MoS2/TiO2 electrocatalyst. These results demonstrate the potential of composite electrocatalysts for HER based on earth abundant, cost-effective, and environmentally friendly materials, which can also be of interest for a broader range of scalable applications in renewable energies, such as lithium sulfur batteries, solar cells, and fuel cells.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
acidic, alkaline, catalyst, hydrogen evolution reaction, MoS2, TiO2
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-73610 (URN)10.1021/acsaem.8b02119 (DOI)000462944700053 ()2-s2.0-85064810223 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-04-12 (oliekm)

Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2022-10-27Bibliographically approved
Ibupoto, Z., Tahira, A., Tang, P., Liu, X., Morante, J. R., Fahlman, M., . . . Vomiero, A. (2019). MoSx@NiO Composite Nanostructures: An Advanced Nonprecious Catalyst for Hydrogen Evolution Reaction in Alkaline Media. Advanced Functional Materials, 29(7), Article ID 1807562.
Open this publication in new window or tab >>MoSx@NiO Composite Nanostructures: An Advanced Nonprecious Catalyst for Hydrogen Evolution Reaction in Alkaline Media
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2019 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, no 7, article id 1807562Article in journal (Refereed) Published
Abstract [en]

The design of the earth‐abundant, nonprecious, efficient, and stable electrocatalysts for efficient hydrogen evolution reaction (HER) in alkaline media is a hot research topic in the field of renewable energies. A heterostructured system composed of MoSx deposited on NiO nanostructures (MoSx@NiO) as a robust catalyst for water splitting is proposed here. NiO nanosponges are applied as cocatalyst for MoS2 in alkaline media. Both NiO and MoS2@NiO composites are prepared by a hydrothermal method. The NiO nanostructures exhibit sponge‐like morphology and are completely covered by the sheet‐like MoS2. The NiO and MoS2 exhibit cubic and hexagonal phases, respectively. In the MoSx@NiO composite, the HER experiment in 1 m KOH electrolyte results in a low overpotential (406 mV) to produce 10 mA cm−2 current density. The Tafel slope for that case is 43 mV per decade, which is the lowest ever achieved for MoS2‐based electrocatalyst in alkaline media. The catalyst is highly stable for at least 13 h, with no decrease in the current density. This simple, cost‐effective, and environmentally friendly methodology can pave the way for exploitation of MoSx@NiO composite catalysts not only for water splitting, but also for other applications such as lithium ion batteries, and fuel cells.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
alkaline media, electrolysis, MoS x @NiO composites
National Category
Other Physics Topics
Research subject
Experimental Physics
Identifiers
urn:nbn:se:ltu:diva-72878 (URN)10.1002/adfm.201807562 (DOI)000459719800018 ()2-s2.0-85059344786 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-13 (johcin)

Available from: 2019-02-13 Created: 2019-02-13 Last updated: 2022-10-27Bibliographically approved
Aftab, A., Ismail, A. R., Ibupoto, Z., Akeiber, H. J. & Malghani, M. (2017). Nanoparticles based drilling muds a solution to drill elevated temperature wells: a review. Renewable & sustainable energy reviews, 76, 1301-1313
Open this publication in new window or tab >>Nanoparticles based drilling muds a solution to drill elevated temperature wells: a review
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2017 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 76, p. 1301-1313Article in journal (Refereed) Published
Abstract [en]

Demand of the oil and gas energy is increasing very drastically. Conventional hydrocarbon reservoirs contain below the sealing cap rock (shale) and easily move towards wellbore are at the depletion stage. Therefore, drilling engineers in collaboration with mud engineers, geologists and geophysicists are looking for innovative materials to drill unconventional hydrocarbons reservoir which are distributed at the basin scale and cannot approach easily. Geo-thermal energy wells and most of unconventional reservoirs are occurred at high pressure high temperature (HPHT) conditions. Conventional micro-macro organic drilling mud additives with heat insulator in nature can minimize efficiency while drilling HPHT wells. Oil-based muds (OBM) are strictly restricted due to high toxic level and poor emulsion stability at HT. However, this review suggests that addition of macro size organic particles and inorganic nanoparticles can enhance rheological performance, reduce filtrate loss volume and improve shale inhibition characteristics of environmental friendly water-based mud (WBM). Despite an impressive amount of experimental work has been done over drilling additives and their effect over rheological and shale inhibition, taking into account their literature review are rare. In addition, there is no review work of the knowledge gained to date. This work will hope fully trigger further development and new research topics in the area of drilling muds system.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Other Physics Topics
Research subject
Experimental physics
Identifiers
urn:nbn:se:ltu:diva-62993 (URN)10.1016/j.rser.2017.03.050 (DOI)000403381300090 ()2-s2.0-85017150764 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-04-11 (andbra)

Available from: 2017-04-11 Created: 2017-04-11 Last updated: 2022-10-27Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-6756-9862

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