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Lin Q, Luo C, Jin D, Zhou L, Zhang R, Wang X. Precise Tuning of Bilayer Ultrasmall MoS 2 Featuring Inhibition of Carrier Recombination and Fast Surface Chemistry for Green H 2 Evolution. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2305888. [PMID: 37726232 DOI: 10.1002/smll.202305888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/31/2023] [Indexed: 09/21/2023]
Abstract
Achieving water splitting to produce green H2 , using the noble-metal-free MoS2 , has attracted huge interest from researchers. However, tuning the number of MoS2 layers precisely while obtaining small lateral sizes to surge the H2 -evolution rate is a tremendous challenge. Here, a bottom-up strategy is designed for the in situ growth of ultrasmall lateral-sized MoS2 with tunable layers on CdS nanorods (CN) by controlling the decomposition temperature and concentration of substrate seed (NH4 )2 MoS4 . Here, the bilayer MoS2 and CN coupling (2L-MoS2 /CN) exhibits the optimum photocatalytic activity. Compared to thicker MoS2 , the 2L-MoS2 has sufficient reduction capacity to drive photocatalytic H2 evolution and the ultrasmall lateral size provides more active sites. Meanwhile, the indirect bandgap, in contrast to the direct bandgap of the monolayer MoS2 , suppresses the carrier recombination transferred to 2L-MoS2 . Under the synergistic effect of both, 2L-MoS2 /CN has fast surface chemical reactions, resulting in the photocatalytic H2 -evolution rate of up to 41.86 mmol g-1 h-1 . A novel strategy is provided here for tuning the MoS2 layers to achieve efficient H2 evolution.
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Affiliation(s)
- Qingzhuo Lin
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, the School of Chemistry and Chemical Engineering, Nanchang University, 999 Xuefu Road, Nanchang, 330031, China
| | - Chonghan Luo
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, the School of Chemistry and Chemical Engineering, Nanchang University, 999 Xuefu Road, Nanchang, 330031, China
| | - Dai Jin
- School of Future Technology, Nanchang University, 999 Xuefu Road, Nanchang, 330031, China
| | - Ling Zhou
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, the School of Chemistry and Chemical Engineering, Nanchang University, 999 Xuefu Road, Nanchang, 330031, China
| | - Rongbin Zhang
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, the School of Chemistry and Chemical Engineering, Nanchang University, 999 Xuefu Road, Nanchang, 330031, China
| | - Xuewen Wang
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, the School of Chemistry and Chemical Engineering, Nanchang University, 999 Xuefu Road, Nanchang, 330031, China
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Nagarajan T, Sridewi N, Wong WP, Walvekar R, Khalid M. Enhanced tribological properties of diesel-based engine oil through synergistic MoS 2-graphene nanohybrid additive. Sci Rep 2023; 13:17424. [PMID: 37833323 PMCID: PMC10575967 DOI: 10.1038/s41598-023-43260-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
This research explores the potential of microwave-synthesized MoS2-graphene nanohybrid as additives to enhance the tribological properties of diesel-based engine oil. The synthesis method offers significant advantages, reducing both synthesis time and energy consumption by 90-98% compared to conventional approaches. The synthesized nanohybrids are characterized through FESEM, EDX, XRD, and Raman spectroscopy to understand their morphology and functional group interactions. These nanohybrids are incorporated into 20W40 engine oil following synthesis, and a comprehensive assessment of their properties is conducted. This evaluation covers critical parameters like viscosity index, stability, volatility, as well as tribological properties, oxidation resistance, and thermal conductivity of the oil-nanohybrid system. Results demonstrate that adding just 0.05 wt% of MoS2-graphene nanohybrid leads to a remarkable 58.82% reduction in friction coefficient and a significant 36.26% decrease in the average wear scar diameter. Additionally, oxidation resistance improves by 19.21%, while thermal conductivity increases notably by 19.83% (at 100 °C). The study demonstrates the synergistic effects of these nanohybrids in reducing friction and wear, enhancing oxidation resistance, and improving thermal conductivity. In conclusion, this research highlights the potential of microwave-synthesized MoS2-graphene nanohybrid as promising tribological additives for diesel engine oils. Their successful integration could significantly enhance the performance and durability of critical mechanical components in diesel engines, representing a significant advancement in lubrication technology.
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Affiliation(s)
- Thachnatharen Nagarajan
- Faculty of Defence Science and Technology, National Defence University of Malaysia, Kuala Lumpur, Malaysia
| | - Nanthini Sridewi
- Faculty of Defence Science and Technology, National Defence University of Malaysia, Kuala Lumpur, Malaysia.
| | - Weng Pin Wong
- Sunway Centre for Electrochemical Energy and Sustainable Technology (SCEEST), School of Engineering and Technology, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, 47500, Petaling Jaya, Selangor, Malaysia
| | - Rashmi Walvekar
- Faculty of Innovation and Technology, School of Engineering, Chemical Engineering Programme, Taylor's University Malaysia, No.1 Jalan Taylor's, 47500, Subang Jaya, Selangor, Malaysia
- Liveable Urban Communities Impact Lab, Taylor's University Malaysia, No.1 Jalan Taylor's, 47500, Subang Jaya, Selangor, Malaysia
| | - Mohammad Khalid
- Sunway Centre for Electrochemical Energy and Sustainable Technology (SCEEST), School of Engineering and Technology, Sunway University, No. 5 Jalan Universiti, Bandar Sunway, 47500, Petaling Jaya, Selangor, Malaysia.
- Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
- Uttaranchal University, Dehradun, Uttarakhand, 248007, India.
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Yu S, Wang P, Ye H, Tang H, Wang S, Wu Z, Pei C, Lu J, Li H. Transition Metal Dichalcogenides Nanoscrolls: Preparation and Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2433. [PMID: 37686941 PMCID: PMC10490124 DOI: 10.3390/nano13172433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/21/2023] [Accepted: 08/25/2023] [Indexed: 09/10/2023]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDCs) nanosheets have shown extensive applications due to their excellent physical and chemical properties. However, the low light absorption efficiency limits their application in optoelectronics. By rolling up 2D TMDCs nanosheets, the one-dimensional (1D) TMDCs nanoscrolls are formed with spiral tubular structure, tunable interlayer spacing, and opening ends. Due to the increased thickness of the scroll structure, the light absorption is enhanced. Meanwhile, the rapid electron transportation is confined along the 1D structure. Therefore, the TMDCs nanoscrolls show improved optoelectronic performance compared to 2D nanosheets. In addition, the high specific surface area and active edge site from the bending strain of the basal plane make them promising materials for catalytic reaction. Thus, the TMDCs nanoscrolls have attracted intensive attention in recent years. In this review, the structure of TMDCs nanoscrolls is first demonstrated and followed by various preparation methods of the TMDCs nanoscrolls. Afterwards, the applications of TMDCs nanoscrolls in the fields of photodetection, hydrogen evolution reaction, and gas sensing are discussed.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Hai Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University, Nanjing 211816, China
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Mombeshora ET, Muchuweni E. Dynamics of reduced graphene oxide: synthesis and structural models. RSC Adv 2023; 13:17633-17655. [PMID: 37312999 PMCID: PMC10258683 DOI: 10.1039/d3ra02098c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/06/2023] [Indexed: 06/15/2023] Open
Abstract
Technological advancements are leading to an upsurge in demand for functional materials that satisfy several of humankind's needs. In addition to this, the current global drive is to develop materials with high efficacy in intended applications whilst practising green chemistry principles to ensure sustainability. Carbon-based materials, such as reduced graphene oxide (RGO), in particular, can possibly meet this criterion because they can be derived from waste biomass (a renewable material), possibly synthesised at low temperatures without the use of hazardous chemicals, and are biodegradable (owing to their organic nature), among other characteristics. Additionally, RGO as a carbon-based material is gaining momentum in several applications due to its lightweight, nontoxicity, excellent flexibility, tuneable band gap (from reduction), higher electrical conductivity (relative to graphene oxide, GO), low cost (owing to the natural abundance of carbon), and potentially facile and scalable synthesis protocols. Despite these attributes, the possible structures of RGO are still numerous with notable critical variations and the synthesis procedures have been dynamic. Herein, we summarize the highlights from the historical breakthroughs in understanding the structure of RGO (from the perspective of GO) and the recent state-of-the-art synthesis protocols, covering the period from 2020 to 2023. These are key aspects in the realisation of the full potential of RGO materials through the tailoring of physicochemical properties and reproducibility. The reviewed work highlights the merits and prospects of the physicochemical properties of RGO toward achieving sustainable, environmentally friendly, low-cost, and high-performing materials at a large scale for use in functional devices/processes to pave the way for commercialisation. This can drive the sustainability and commercial viability aspects of RGO as a material.
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Affiliation(s)
- Edwin T Mombeshora
- Department of Chemistry and Earth Sciences, University of Zimbabwe Mount Pleasant Harare MP167 Zimbabwe
| | - Edigar Muchuweni
- Department of Engineering and Physics, Bindura University of Science Education Bindura Zimbabwe
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