Research

Jump to: Review

9 pages, 2065 KiB

Open AccessCommunication

Octahedral Shaped PbTiO₃-TiO₂ Nanocomposites for High-Efficiency Photocatalytic Hydrogen Production

by Simin Yin, Shun Liu, Yongfeng Yuan, Shaoyi Guo and Zhaohui Ren

Nanomaterials 2021, 11(9), 2295; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11092295 - 03 Sep 2021

Cited by 7 | Viewed by 1651

In this work, octahedral shaped PbTiO₃-TiO₂ nanocomposites have been synthesized by a facile hydrothermal method, where perovskite ferroelectric PbTiO₃ nanooctahedra were employed as substrate. The microstructures of the composites were investigated systemically by using XRD, SEM, TEM and UV-Vis [...] Read more.

In this work, octahedral shaped PbTiO₃-TiO₂ nanocomposites have been synthesized by a facile hydrothermal method, where perovskite ferroelectric PbTiO₃ nanooctahedra were employed as substrate. The microstructures of the composites were investigated systemically by using XRD, SEM, TEM and UV-Vis spectroscopy. It was revealed that anantase TiO₂ nanocrystals with a size of about 5 nm are dispersed on the surface of the {111} facets of the nanooctahedron crystals. Photocatalytic hydrogen production of the nanocomposites has been evaluated in a methanol alcohol-water solution under UV light enhanced irradiation. The H₂ evolution rate of the nanocomposites increased with an increased loading of TiO₂ on the nanooctahedra. The highest H₂ evolution rate was 630.51 μmol/h with the highest concentration of TiO₂ prepared with 2 mL tetrabutyl titanate, which was about 36 times higher than that of the octahedron substrate. The enhanced photocatalytic reactivity of the nanocomposites is possibly ascribed to the UV light absorption of the nanooctahedral substrates, efficient separation of photo-generated carriers via the interface and the reaction on the surface of the TiO₂ nanocrystals. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Figure 1

15 pages, 4932 KiB

Open AccessArticle

Electrospun Fe₃O₄-Sn@Carbon Nanofibers Composite as Efficient Anode Material for Li-Ion Batteries

by Hong Wang, Yuejin Ma and Wenming Zhang

Nanomaterials 2021, 11(9), 2203; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11092203 - 27 Aug 2021

Cited by 1 | Viewed by 3026

Abstract

Nanoscale Fe₃O₄-Sn@CNFs was prepared by loading Fe₃O₄ and Sn nanoparticles onto CNFs synthesized via electrostatic spinning and subsequent thermal treatment by solvothermal reaction, and were used as anode materials for lithium-ion batteries. The prepared anode delivers [...] Read more.

Nanoscale Fe₃O₄-Sn@CNFs was prepared by loading Fe₃O₄ and Sn nanoparticles onto CNFs synthesized via electrostatic spinning and subsequent thermal treatment by solvothermal reaction, and were used as anode materials for lithium-ion batteries. The prepared anode delivers an excellent reversible specific capacity of 1120 mAh·g⁻¹ at a current density of 100 mA·g⁻¹ at the 50th cycle. The recovery rate of the specific capacity (99%) proves the better cycle stability. Fe₃O₄ nanoparticles are uniformly dispersed on the surface of nanofibers with high density, effectively increasing the electrochemical reaction sites, and improving the electrochemical performance of the active material. The rate and cycling performance of the fabricated electrodes were significantly improved because of Sn and Fe₃O₄ loading on CNFs with high electrical conductivity and elasticity. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Figure 1

13 pages, 46216 KiB

Open AccessArticle

Standing and Lying Ni(OH)₂ Nanosheets on Multilayer Graphene for High-Performance Supercapacitors

by Junming Xu, Mengxia Tang, Zhengming Hu, Xiaoping Hu, Tao Zhou, Kaixin Song, Jun Wu and Jipeng Cheng

Nanomaterials 2021, 11(7), 1662; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11071662 - 24 Jun 2021

Cited by 7 | Viewed by 2713

Abstract

For conventional synthesis of Ni(OH)₂/graphene hybrids, oxygen-containing functional groups should be firstly introduced on graphene to serve as active sites for the anchoring of Ni(OH)₂. In this work, a method for growing Ni(OH)₂ nanosheets on multilayer graphene (MLG) [...] Read more.

For conventional synthesis of Ni(OH)₂/graphene hybrids, oxygen-containing functional groups should be firstly introduced on graphene to serve as active sites for the anchoring of Ni(OH)₂. In this work, a method for growing Ni(OH)₂ nanosheets on multilayer graphene (MLG) with molecular connection is developed which does not need any pre-activation treatments. Moreover, Ni(OH)₂ nanosheets can be controlled to stand or lie on the surface of MLG. The prepared hybrids were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The growth processes are suggested according to their morphologies at different growth stages. The enhanced electrochemical performances as supercapacitor electrode materials were confirmed by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques. Ni(OH)₂ nanosheets standing and lying on MLG show specific capacities of 204.4 mAh g⁻¹ and 131.7 mAh g⁻¹, respectively, at 1 A g⁻¹ based on the total mass of the hybrids and 81.5% and 92.8% capacity retention at a high current density of 10 A g⁻¹, respectively. Hybrid supercapacitors with as-prepared hybrids as cathodes and activated carbon as anode were fabricated and tested. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Figure 1

11 pages, 4278 KiB

Open AccessArticle

Synthesis and Study on Ni-Co Phosphite/Activated Carbon Fabric Composited Materials with Controllable Nano-Structure for Hybrid Super-Capacitor Applications

by Dalai Jin, Jiamin Zhou, Tianpeng Yang, Saisai Li, Lina Wang, Yurong Cai and Longcheng Wang

Nanomaterials 2021, 11(7), 1649; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11071649 - 23 Jun 2021

Cited by 2 | Viewed by 2015

Abstract

The advantage of low resistivity and inactive binders makes binder-free electrode an excellent candidate for high-performance energy devices. A simple hydrothermal method was used to fabricate M₁₁(HPO₃)₈(OH)₆ (M: Ni and Co) (MHP) arrays combined with activated [...] Read more.

The advantage of low resistivity and inactive binders makes binder-free electrode an excellent candidate for high-performance energy devices. A simple hydrothermal method was used to fabricate M₁₁(HPO₃)₈(OH)₆ (M: Ni and Co) (MHP) arrays combined with activated carbon fabric (ACF) without binder. The structures of MHP can be easily tuned from bouquets to nano-sheets by the concentration of NaH₂PO₂. The MHP/ACF composite materials with different structures showed the typical battery-type characteristic of anodic electrodes. In a three-electrode cell configuration, the MHP nano-sheet arrays/ACF composite has a higher capacity, of 1254 F/g, at a scan rate of 10 mA/cm² and shows better cycling stability: 84.3% remaining specific capacity after 1000 cycles of charge-discharge measurement. The composite is highly flexible, with almost the same electrochemical performance under stretching mode. The MHP/ACF composite@ACF hybrid supercapacitor can deliver the highest energy density, of 34.1 Wh·kg⁻¹, and a power density of 722 W·kg⁻¹ at 1 A·g⁻¹. As indicated by the results, MHP/ACF composite materials are excellent binder-free electrodes, candidates for flexible high-performance hybrid super-capacitor devices. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Figure 1

12 pages, 4727 KiB

Open AccessArticle

High-Capacity and Long-Lifespan Aqueous LiV₃O₈/Zn Battery Using Zn/Li Hybrid Electrolyte

by Qiang Pang, Xiangyu Yu, Shijing Zhang, Wei He, Siyu Yang, Yao Fu, Ying Tian, Mingming Xing and Xixian Luo

Nanomaterials 2021, 11(6), 1429; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11061429 - 28 May 2021

Cited by 8 | Viewed by 3236

Abstract

Aqueous zinc-ion batteries (AZIBs) are promising candidates for large-scale energy storage because of their low cost and high safety. However, their practical applications are impeded by low energy density and short service life. Here, an aqueous Zn²⁺/Li⁺ hybrid-ion battery is [...] Read more.

Aqueous zinc-ion batteries (AZIBs) are promising candidates for large-scale energy storage because of their low cost and high safety. However, their practical applications are impeded by low energy density and short service life. Here, an aqueous Zn²⁺/Li⁺ hybrid-ion battery is fabricated using the LiV₃O₈ nanorods as the cathode, metallic Zn as the anode, and 3 M Zn(OTf)₂ + 0.5 M LiOTf aqueous solution as the electrolyte. Compared with the batteries using pure 3 M Zn(OTf)₂ electrolyte, the cycle performance of the hybrid-ion battery is significantly improved. After 4000 cycles at 5 A g¹, the remaining capacity is 163.9 mA h g⁻¹ with impressive capacity retention of 87.0%. Ex-situ XRD, ex-situ XPS, and SEM tests demonstrate that the hybrid electrolyte can inhibit the formation of the irreversible Zn₃(OH)₂V₂O₇·2H₂O by-product and restrict Zn dendrite growth during cycling, thereby improving the cycle performance of the batteries. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Figure 1

9 pages, 2188 KiB

Open AccessArticle

Effect of Co Doping on Electrocatalytic Performance of Co-NiS₂/CoS₂ Heterostructures

by Zehui Peng, Shuai Lou, Yuan Gao, Lijun Kong, Shancheng Yan, Ka Wang and Haizeng Song

Nanomaterials 2021, 11(5), 1245; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11051245 - 08 May 2021

Cited by 3 | Viewed by 2167

Abstract

There are abundant water resources in nature, and hydrogen production from electrolyzed water can be one of the main ways to obtain green and sustainable energy. Traditional water electrolysis uses precious metals as catalysts, but it is difficult to apply in massive volumes [...] Read more.

There are abundant water resources in nature, and hydrogen production from electrolyzed water can be one of the main ways to obtain green and sustainable energy. Traditional water electrolysis uses precious metals as catalysts, but it is difficult to apply in massive volumes due to low reserves and high prices. It is still a challenge to develop hydrogen electrocatalysts with excellent performance but low cost to further improve the efficiency of hydrogen production. This article reported a potential candidate, the Co-NiS₂/CoS₂ (material is based on NiS₂, and after Co doping, The NiS₂/CoS₂ heterostructure is formed) heterostructures, prepared by hydrothermal method with carbon paper as the substrate. In a 0.5 M sulfuric acid solution, the hydrogen evolution reaction with Co-NiS₂/CoS₂ as the electrode showed excellent catalytic performance. When the Co (Cobalt) doping concentration is increased to 27%, the overpotential is −133.3 mV, which is a drop of 81 mV compared with −214.3 mV when it is not doped. The heterostructure formed after doping also has good stability. After 800 CV cycles, the difference in overpotential is only 3 mV. The significant improvement of the catalytic performance can be attributed to the significant changes in the crystal structure and properties of the doped heterostructures, which provide an effective method for efficient electrocatalytic hydrogen production. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Figure 1

8 pages, 1726 KiB

Open AccessCommunication

Chemically Roughened, Sputtered Au Films with Trace-Loaded Manganese Oxide for both On-Chip and Off-Chip High Frequency Supercapacitors

by Pai Lu, Haitao Xue, Wentao Liu, Zhongbao Feng and Qiang Sun

Nanomaterials 2021, 11(2), 257; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11020257 - 20 Jan 2021

Cited by 3 | Viewed by 1547

Abstract

High frequency supercapacitors (HFSCs) are promising in alternating current line filtering and adaptable storage of high-frequency pulse electrical energy. Herein, we report a facile yet integrated-circuit-compatible fabrication of HFSC electrodes by combining chemical roughening of the sputtered metal (Au) films and in situ [...] Read more.

High frequency supercapacitors (HFSCs) are promising in alternating current line filtering and adaptable storage of high-frequency pulse electrical energy. Herein, we report a facile yet integrated-circuit-compatible fabrication of HFSC electrodes by combining chemical roughening of the sputtered metal (Au) films and in situ trace loading of a pseudocapacitive material (MnO_x). The developed electrode fabrication route is versatile for different substrates, and is described with the application paradigms of both on-chip (with Si/SiO₂ substrate) and off-chip (without Si/SiO₂ substrate, with Ti substrate as an example in this study) HFSCs. With Au/MnO_x films on Si/SiO₂ substrates as the working electrodes, the derived on-chip HFSC displayed satisfactory performance in high frequency applications (i.e., an areal capacitance of 131.7 µF cm⁻², a phase angle of −78°, and a RC time constant of 0.27 ms, at 120 Hz). Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Figure 1

14 pages, 6870 KiB

Open AccessArticle

Ni-Rich Layered Oxide with Preferred Orientation (110) Plane as a Stable Cathode Material for High-Energy Lithium-Ion Batteries

by Fangkun Li, Zhengbo Liu, Jiadong Shen, Xijun Xu, Liyan Zeng, Yu Li, Dechao Zhang, Shiyong Zuo and Jun Liu

Nanomaterials 2020, 10(12), 2495; https://0-doi-org.brum.beds.ac.uk/10.3390/nano10122495 - 11 Dec 2020

Cited by 21 | Viewed by 4717

Abstract

The cathode, a crucial constituent part of Li-ion batteries, determines the output voltage and integral energy density of batteries to a great extent. Among them, Ni-rich LiNi_xCo_yMn_zO₂ (x + y + z = 1, x ≥ [...] Read more.

The cathode, a crucial constituent part of Li-ion batteries, determines the output voltage and integral energy density of batteries to a great extent. Among them, Ni-rich LiNi_xCo_yMn_zO₂ (x + y + z = 1, x ≥ 0.6) layered transition metal oxides possess a higher capacity and lower cost as compared to LiCoO₂, which have stimulated widespread interests. However, the wide application of Ni-rich cathodes is seriously hampered by their poor diffusion dynamics and severe voltage drops. To moderate these problems, a nanobrick Ni-rich layered LiNi_0.6Co_0.2Mn_0.2O₂ cathode with a preferred orientation (110) facet was designed and successfully synthesized via a modified co-precipitation route. The galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) analysis of LiNi_0.6Co_0.2Mn_0.2O₂ reveal its superior kinetic performance endowing outstanding rate performance and long-term cycle stability, especially the voltage drop being as small as 67.7 mV at a current density of 0.5 C for 200 cycles. Due to its unique architecture, dramatically shortened ion/electron diffusion distance, and more unimpeded Li-ion transmission pathways, the current nanostructured LiNi_0.6Co_0.2Mn_0.2O₂ cathode enhances the Li-ion diffusion dynamics and suppresses the voltage drop, thus resulting in superior electrochemical performance. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures

Graphical abstract

Review

Jump to: Research

39 pages, 24378 KiB

Open AccessReview

Advances in Electrochemical Energy Devices Constructed with Tungsten Oxide-Based Nanomaterials

by Wenfang Han, Qian Shi and Renzong Hu

Nanomaterials 2021, 11(3), 692; https://0-doi-org.brum.beds.ac.uk/10.3390/nano11030692 - 10 Mar 2021

Cited by 21 | Viewed by 5074

Abstract

Tungsten oxide-based materials have drawn huge attention for their versatile uses to construct various energy storage devices. Particularly, their electrochromic devices and optically-changing devices are intensively studied in terms of energy-saving. Furthermore, based on close connections in the forms of device structure and [...] Read more.

Tungsten oxide-based materials have drawn huge attention for their versatile uses to construct various energy storage devices. Particularly, their electrochromic devices and optically-changing devices are intensively studied in terms of energy-saving. Furthermore, based on close connections in the forms of device structure and working mechanisms between these two main applications, bifunctional devices of tungsten oxide-based materials with energy storage and optical change came into our view, and when solar cells are integrated, multifunctional devices are accessible. In this article, we have reviewed the latest developments of tungsten oxide-based nanostructured materials in various kinds of applications, and our focus falls on their energy-related uses, especially supercapacitors, lithium ion batteries, electrochromic devices, and their bifunctional and multifunctional devices. Additionally, other applications such as photochromic devices, sensors, and photocatalysts of tungsten oxide-based materials have also been mentioned. We hope this article can shed light on the related applications of tungsten oxide-based materials and inspire new possibilities for further uses. Full article

(This article belongs to the Special Issue State-of-the-Art in Nanomaterials for Energy and Catalysis in China)

► Show Figures