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Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide
Zirconia and 10%, 20%, and 30% cerium-doped zirconia nanoparticles (ZCO), ZCO-1, ZCO-2, and ZCO-3, respectively, were prepared using auto-combustion method. Binary nanohybrids, ZrO(2)@rGO and ZCO-2@rGO (rGO = reduced graphene oxide), and ternary nanohybrids, ZrO(2)@rGO@MoS(2) and ZCO-2@rGO@MoS(2,) h...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221905/ https://www.ncbi.nlm.nih.gov/pubmed/32276478 http://dx.doi.org/10.3390/nano10040707 |
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author | Verma, Dinesh Kumar Shukla, Nivedita Kumar, Bharat Singh, Alok Kumar Shahu, Kavita Yadav, Mithilesh Rhee, Kyong Yop Rastogi, Rashmi Bala |
author_facet | Verma, Dinesh Kumar Shukla, Nivedita Kumar, Bharat Singh, Alok Kumar Shahu, Kavita Yadav, Mithilesh Rhee, Kyong Yop Rastogi, Rashmi Bala |
author_sort | Verma, Dinesh Kumar |
collection | PubMed |
description | Zirconia and 10%, 20%, and 30% cerium-doped zirconia nanoparticles (ZCO), ZCO-1, ZCO-2, and ZCO-3, respectively, were prepared using auto-combustion method. Binary nanohybrids, ZrO(2)@rGO and ZCO-2@rGO (rGO = reduced graphene oxide), and ternary nanohybrids, ZrO(2)@rGO@MoS(2) and ZCO-2@rGO@MoS(2,) have been prepared with an anticipation of a fruitful synergic effect of rGO, MoS(2), and cerium-doped zirconia on the tribo-activity. Tribo-activity of these additives in paraffin oil (PO) has been assessed by a four-ball lubricant tester at the optimized concentration, 0.125% w/v. The tribo-performance follows the order: ZCO-2@rGO@MoS(2) > ZrO(2)@rGO@MoS(2) > ZCO-2@rGO > ZrO(2)@rGO > MoS(2) > ZrO(2) > rGO > PO. The nanoparticles acting as spacers control restacking of the nanosheets provided structural augmentation while nanosheets, in turn, prevent agglomeration of the nanoparticles. Doped nanoparticles upgraded the activity by forming defects. Thus, the results acknowledge the synergic effect of cerium-doped zirconia and lamellar nanosheets of rGO and MoS(2). There is noncovalent interaction among all the individuals. Analysis of the morphological features of wear-track carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM) in PO and its formulations with various additives is consistent with the above sequence. The energy dispersive X-ray (EDX) spectrum of ZCO-2@rGO@MoS(2) indicates the existence of zirconium, cerium, molybdenum, and sulfur on the wear-track, confirming, thereby, the active role played by these elements during tribofilm formation. The X-ray photoelectron spectroscopy (XPS) studies of worn surface reveal that the tribofilm is made up of rGO, zirconia, ceria, and MoS(2) along with Fe(2)O(3), MoO(3), and SO(4)(2−) as the outcome of the tribo-chemical reaction. |
format | Online Article Text |
id | pubmed-7221905 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-72219052020-05-22 Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide Verma, Dinesh Kumar Shukla, Nivedita Kumar, Bharat Singh, Alok Kumar Shahu, Kavita Yadav, Mithilesh Rhee, Kyong Yop Rastogi, Rashmi Bala Nanomaterials (Basel) Article Zirconia and 10%, 20%, and 30% cerium-doped zirconia nanoparticles (ZCO), ZCO-1, ZCO-2, and ZCO-3, respectively, were prepared using auto-combustion method. Binary nanohybrids, ZrO(2)@rGO and ZCO-2@rGO (rGO = reduced graphene oxide), and ternary nanohybrids, ZrO(2)@rGO@MoS(2) and ZCO-2@rGO@MoS(2,) have been prepared with an anticipation of a fruitful synergic effect of rGO, MoS(2), and cerium-doped zirconia on the tribo-activity. Tribo-activity of these additives in paraffin oil (PO) has been assessed by a four-ball lubricant tester at the optimized concentration, 0.125% w/v. The tribo-performance follows the order: ZCO-2@rGO@MoS(2) > ZrO(2)@rGO@MoS(2) > ZCO-2@rGO > ZrO(2)@rGO > MoS(2) > ZrO(2) > rGO > PO. The nanoparticles acting as spacers control restacking of the nanosheets provided structural augmentation while nanosheets, in turn, prevent agglomeration of the nanoparticles. Doped nanoparticles upgraded the activity by forming defects. Thus, the results acknowledge the synergic effect of cerium-doped zirconia and lamellar nanosheets of rGO and MoS(2). There is noncovalent interaction among all the individuals. Analysis of the morphological features of wear-track carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM) in PO and its formulations with various additives is consistent with the above sequence. The energy dispersive X-ray (EDX) spectrum of ZCO-2@rGO@MoS(2) indicates the existence of zirconium, cerium, molybdenum, and sulfur on the wear-track, confirming, thereby, the active role played by these elements during tribofilm formation. The X-ray photoelectron spectroscopy (XPS) studies of worn surface reveal that the tribofilm is made up of rGO, zirconia, ceria, and MoS(2) along with Fe(2)O(3), MoO(3), and SO(4)(2−) as the outcome of the tribo-chemical reaction. MDPI 2020-04-08 /pmc/articles/PMC7221905/ /pubmed/32276478 http://dx.doi.org/10.3390/nano10040707 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Verma, Dinesh Kumar Shukla, Nivedita Kumar, Bharat Singh, Alok Kumar Shahu, Kavita Yadav, Mithilesh Rhee, Kyong Yop Rastogi, Rashmi Bala Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide |
title | Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide |
title_full | Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide |
title_fullStr | Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide |
title_full_unstemmed | Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide |
title_short | Synergistic Tribo-Activity of Nanohybrids of Zirconia/Cerium-Doped Zirconia Nanoparticles with Nano Lamellar Reduced Graphene Oxide and Molybdenum Disulfide |
title_sort | synergistic tribo-activity of nanohybrids of zirconia/cerium-doped zirconia nanoparticles with nano lamellar reduced graphene oxide and molybdenum disulfide |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221905/ https://www.ncbi.nlm.nih.gov/pubmed/32276478 http://dx.doi.org/10.3390/nano10040707 |
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