Bismuth nanosheets grown on carbon fiber cloth as advanced binder-free anode for sodium-ion batteries

The bismuth nanosheets grown on carbon fiber cloth were designed. For sodium-ion batteries, the Bi/CFC electrode exhibited a high reversible capacity of 350 and 240 mAh g^− 1 after 300 cycles at 50 and 200 mA g^− 1, as well as a good rate capability. Besides, the electrode displayed two flat potential profiles during the charge/discharge process. The results suggest that the Bi/CFC electrode has excellent potential as an anode for sodium-ion batteries.     

Facile synthesis of scheelite-type NdOsO4 directly grown on carbon cloth for oxygen evolution reaction

Journal of Solid State Electrochemistry - In the recent work, the scheelite-type ABO4 compound (A = Nd and B = Os) is synthesized via a hydrothermal route directly...     

Facile synthesis of sheet-shaped Co2P grown on carbon cloth as a high-performance electrocatalyst for the hydrogen evolution reaction

Journal of Solid State Electrochemistry - Here, we demonstrate the synthesis of sheet-shaped Co2P grown on carbon cloth (sheet-shaped Co2P-CC) through a facile route. Electrochemical measurements...     

A binder-free Ge-nanoparticle anode assembled on multiwalled carbon nanotube networks for Li-ion batteries

Germanium (Ge) nanoparticle-multiwalled carbon nanotube (MWCNT) anodes are fabricated through the anchoring of Ge on the surface of electrophoretically pre-deposited MWCNT networks via a thermal evaporation process. This Ge-MWCNT nanocomposite displays a large reversible capacity of over 800 mA h g(-1) at 1 C even after 200 cycles.     

Co/N-doped carbon nanotube arrays grown on 2D MOFs-derived matrix for boosting the oxygen reduction reaction in alkaline and acidic media

The development of high-performance and cost-effective electrocatalysts towards oxygen reduction reaction(ORR) is of significant importance,but still challenging for the practical applications in related energy systems.ORR process typically suffers from sluggish kinetics,the exploration of ORR electrocatalyst thus requires elaborate design.Herein,an effective strategy is developed for growing Co/N-doped carbon nanotube arrays on 2D MOFs-derived matrix via the pyrolysis of Co/Zn metalorganic-framework(MOF) nanosheets.The Co/Zn-MOF nanosheets serve as both the self-template for the 2D carbonized framework morphology and C/N source for the in-situ growth of 1D N-doped carbon nanotubes.The constructed hie rarchical architecture effectively integrates the OD/1D Co nanoparticle/Ndoped carbon nanotube interface and 1D(nanotubes)/2D(nanosheets) junction into frameworks with highly exposed active surface,enhanced mass-transport kinetics and electrical conductivity.As a result,the designed composite exhibits superior ORR activity and durability in alkaline media as compared to commercial Pt/C.Particularly,it shows promising ORR performance with a half-wave potential of 0.78 V versus reversible hydrogen electrode and negligible activity attenuation after 5000 potential cycles in acidic electrolyte.The designed strategy can be extended to construct other MOFs-derived carbon matrixes with diverse hierarchical structures and provide an efficient avenue for searching highperformance electrocatalysts.     

Ultra-small Co/CoOx nanoparticles dispersed on N-doped carbon nanosheets for highly efficient electrocatalytic oxygen evolution reaction

In this paper,we report a facile strategy to synthesize Co-BDC-NH2 material,which is used as a precursor towards an excellent OER electrocatalyst by thermal annealing in nitrogen.Ultra-small Co/Co Oxnanoparticles were uniformly dispersed on the rhombus N-doped carbon(NC)nanoflakes.Transmission electron microscopic,X-ray diffraction spectrometric,and X-ray photoelectron spectroscopic analyses revealed the coexistence of metallic Co and Co oxides nanoparticles.It was found that Co/CoO_x@NC obtained at 500℃ annealing temperature exhibited the highest electrocatalytic OER activity,with 307 and375 m V overpotential to achieve 10 and 100 m A cm^-2 current densities.Besides,thanks to the in-situ annealing process,Co/CoO_x@NC showed excellent catalytic stability with 97.4%current density retention after 24 h electrolysis at 1.66 V vs.RHE electrode potential.Further investigations revealed that the ultrasmall Co/Co Oxnanoparticles distributed on N-doped carbon template contribute significantly towards OER electrocatalysis through enlarging the activity surface areas and enhancing the intrinsic electrochemical activity due to the presence of metallic Co.     

Cycling effects on interfacial reliability of TiO<Subscript>2</Subscript> anode film in thin film lithium-ion microbatteries

This work presents a comprehensive study on the cycling effects on morphological, nanomechanical, and interfacial properties of sputtered TiO₂ anode film during discharge/charge cycling. TiO₂ film mechanically fails due to the repeated volume change and related generation/relaxation of stress induced by electrochemical phase transformation. The induced stress intensifies the initiation/propagation of cracks, also the interfacial delamination. Both morphology and mechanical property changes have harmful effects on the electrical contact, resulting in the battery aging. This paper also demonstrates that the experiment and analysis method is effective to characterize the interfacial reliability within thin film microbatteries.     

Microwave synthesis of NiSe2 nanomaterials on carbon fiber felt for flexible supercapacitors and oxygen evolution reaction

Journal of Solid State Electrochemistry - In this paper, NiSe2 materials were synthesized on carbon fiber felts (CFF) using a convenient one-step microwave approach. Self-supporting NiSe2/CFF is a...     

无模板合成微米管状Co3O4基复合材料高效催化电解水析氧反应

电解水制氢因具有清洁高效的优点而被认为是大规模生产氢能最有希望的技术之一.然而,电解水半反应之一的析氧反应(OER)需经历复杂且动力学缓慢的4电子转移过程.加之热力学上的阻碍,OER实际需要的电位远大于1.23 V的理论值,导致其能耗高,限制了电解水的效率和商业化应用.因此,亟待开发高效的OER电催化剂.管状结构具有较高的比表面积、充分暴露的活性位点和丰富的短路径扩散通道,是一种理想的电催化结构.同时,Co3O4基材料因其制备容易、成本低和OER电催化学活性较高等特点,成为近年来电催化材料的研究热点.此外,非金属元素P的掺杂条件温和,并且可以有效改变过渡金属电子结构.因此,本文通过合理设计管状的Co3O4基电催化剂并进行P掺杂,尝试将形貌调控和元素改性的优势发挥到最大.为了解析影响生成管状结构的因素,本文通过控制变量法系统地研究了管状Ni/Co3O4的制备条件,包括阳离子种类和含量、添加剂种类和含量、阴离子种类等对催化剂形貌和性能的影响.表征结果表明,初始的乙酸钴镍氢氧化物棱柱对反应环境较为敏感,从而成为直接影响最终微米管状结构的关键因素.此外,对Ni/Co3O4微米管进行适量的P掺杂,能提高材料的电子传输性能和优化材料的电子结构;而且P的掺杂直接提高了样品中的M3+/M2+比例(M代表Co和Ni),而M3+是M基电催化材料的活性位点,这进一步增加了OER的活性位点进而提高其催化活性.总之,通过结构和成分的优化,得到了OER催化性能显著提高的微米管状P-Ni/Co3O4,其性能甚至超过了商业化RuO2电催化剂.     

Electrodeposition of cobalt-sulfide nanosheets film as an efficient electrocatalyst for oxygen evolution reaction

In this communication, we report the development of cobalt-sulfide nanosheets film on Ti mesh (Co-S/Ti mesh) via electrodeposition as a novel oxygen evolution anode in basic media. Electrochemical experiments suggest that this Co-S/Ti mesh electrode exhibits high catalytic activity and good stability. It needs overpotential of 361 mV to drive current density of 10 mA cm^− 2 and its catalytic activity is maintained for at least 20 h.     

Preparation of hybrid thin film modified carbon nanotubes on glassy carbon electrode and its electrocatalysis for oxygen reduction

A hybrid thin film containing Pt nanoparticles and [tetrakis(N-methylpyridyl)porphyrinato]cobalt (CoTMPyP) modified multi-walled carbon nanotubes (MWNTs) on a glassy carbon (GC) electrode surface was fabricated. This hybrid film electrode exhibited remarkable electrocatalytic activity for oxygen reduction and high stability with promising applications in fuel cells.     

Implanting Ni into N-doped puffed carbon: A new advanced electrocatalyst for oxygen evolution reaction

Tailored design and synthesis of high-quality electrocatalysts is vital for the advancement of oxygen evolution reaction (OER). Herein, we report a powerful puffing method to fabricate hierarchical porous N-doped carbon with numerous embedded Ni nanoparticles. Interestingly, during the puffing and annealing process, rice precursor with N and Ni sources can be in-situ converted into Ni-embedded N-doped porous carbon (N-PC/Ni) composite. The obtained N-PC/Ni composite possesses a cross-linked porous architecture containing conductive carbon backbone and active Ni nanoparticles electrocatalysts for OER. The pore formation in N-PC/Ni composite is also proposed because of carbothermic reduction. The N-PC/Ni composite is fully studied as electrocatalysts for OER. Due to increased active surface area, enhanced electronic conductivity and reactivity, the designed N-PC/Ni composite exhibits superior OER performance with a low Tafel slope (∼88 mV/dec) and a low overpotential as well as excellent long-term stability in alkaline solution. Our proposed rational design strategy may provide a new way to construct other advanced metal/heteroatom-doped composites for widespread application in electrocatalysis.     

溶剂热法制备磷掺杂碳纳米管作为氧气还原和氧气析出反应双功能电催化剂的研究

对氧气还原(ORR)和氧气析出(OER)反应都具有催化活性的双功能催化剂在金属-空气电池中起着关键作用.本文通过溶剂热反应,一步原位合成了磷掺杂碳纳米管(P-CNT).旋转环盘电极测试表明磷掺杂能够明显提高碳纳米管的催化活性,P-CNT在碱性电解质中对ORR和OER都具有优异的催化活性.P-CNT对ORR的催化还原为近4电子反应,可与商业催化剂Pt/C(20 wt%)相比;而其对OER的催化活性则高于Pt/C(20 wt%).此外,P-CNT的长期稳定性优于Pt/C(20 wt%).P-CNT对ORR和OER的高催化活性和稳定性主要归因于磷对碳的掺杂以及磷与碳间强的化学键合.     

弱磁性Co0.85Se纳米片负载碳纳米管作为电催化析氢催化剂

氢气是一种环境友好可再生的清洁能源,电解水无疑是一种很好的制氢方法.然而,电催化分解水析氢受到其缓慢的动力学过程、较低的催化性能和较差的稳定性的限制.为了使整个过程更节能,具有高电流密度和低的过电势的高效电催化剂被广泛研究.非化学计量相硒化钴(Co0.85Se)作为一种重要的金属硫属化合物具有优异的催化性能而广受关注.但是低维的Co0.85Se活性位点少,分散性差,电子传递能力低,导致其电催化剂活性差.多壁碳纳米管(MWCNTs)具有多种电性能,包括金属导电性和电子存储能力等.因此,MWCNTs的特殊结构和高导电性可以有效地促进电子从电催化剂向碳纳米管的转移,实现高效电分解水制氢性能.本文在不使用表面活性剂和模板的情况下,通过一步水热溶剂热法合成弱磁性Co0.85Se纳米片负载碳纳米管电催化剂.采用磁滞回线研究Co0.85Se和MWCNTs/Co0.85Se的磁性能,结果表明其有弱顺磁性,Co0.85Se纳米片之间的空间距离增强导致粒子间偶极相互作用减弱,从而使MWCNTs/Co0.85Se纳米复合材料的矫顽力值增加到158 Oe.随着微晶尺寸的减小和纳米颗粒间距的增大,MWCNTs/Co0.85Se催化剂的比表面积增大,有利于提高其电催化活性.扫描电镜和透射电镜展示出Co0.85Se纳米片分散性较差,且团聚现象严重,而MWCNTs/Co0.85Se纳米复合催化剂显示Co0.85Se纳米片均匀分散在MWCNTs表面,且纳米片尺寸明显减小,有利于Co0.85Se纳米片暴露更多的活性位点.线性扫描伏安曲线测量表明,在酸性溶液中Co0.85Se纳米片在电流密度为10 mA cm?2时,其过电势为319 mV(vs.RHE),30 wt%MWCNTs/Co0.85Se的过电势为266 mV(vs.RHE).Co0.85Se和MWCNTs/Co0.85Se的Tafel斜率分别为92.6和60.5 mV dec?1.此外,MWCNTs/Co0.85Se的电流交换密度(j0)为0.07 mA cm?2.较小的Tafel斜率和高的电流交换密度表明,MWCNTs/Co0.85Se具有良好的反应动力学和快速的质子分离速率.交流阻抗谱表明MWCNTs/Co0.85Se比Co0.85Se电阻更小,电子传输速率更快.电化学活性表面积与双电层在固液界面处的电容测量值成正比.结果显示,30 wt%MWCNTs/Co0.85Se的双电层电容为0.22 mF cm^-2,高于Co0.85Se和15 wt%的rGO/Co0.85Se(0.04 mF cm^-2,0.17 mF cm^-2),这表明较大的电化学活性表面积有利于析氢反应进行.30 wt%MWCNTs/Co0.85Se的循环稳定测试表明其具有较好的稳定性.综上,本文介绍了通过一步水热法合成具有弱磁性的Co0.85Se和MWCNTs/Co0.85Se电催化剂,碳纳米管作为一种高导电性材料被引入Co0.85Se纳米片中以减少Co0.85Se的团聚,使Co0.85Se的活性位点增加,进而提高电催化制氢性能.     

CoP@SiO2nanoreactors: A core-shell structure for efficient electrocatalytic oxygen evolution reaction

Metallic phosphides as a crucial class of metal-like compounds show high electric conductivity and electrochemical properties. It is of significant benefit to understanding the relationship between the electrocatalytic performance and phosphating degree of precursors. In this work, using Co₃O₄@SiO₂ as precursor, core-shell structured CoP@SiO₂ nanoreactors with outstanding oxygen evolution reaction performance were synthesized through a facile calcination method. The electrocatalytic performance of CoP@SiO₂ modified electrode that treated with 500 mg NaH₂PO₂ was greatly enhanced. The obtained product displays a low overpotential of 280 mV at a current density of 10 mA/cm² and a Tafel value 89 mV/dec in alkaline conditions. The easy available CoP@SiO₂ with outstanding catalytic performance and stability possesses huge potential in future electrochemical applications.     

Co1-xS embedded in porous carbon derived from metal organic framework as a highly efficient electrocatalyst for oxygen evolution reaction

Here, we report a two-step conversion method to fabricate a composite of Co_1-xS embedded in porous carbon framework (Co_1-xS@C) derived from metal organic frameworks (MOFs). The as-prepared porous dodecahedron Co_1-xS@C composite catalyst exhibits excellent electrocatalytic performance towards oxygen evolution reaction (OER).     

Promoting effect of nitrogen doping on carbon nanotube-supported RuO_2 applied in the electrocatalytic oxygen evolution reaction

RuO_2 nanoparticles supported on multi-walled carbon nanotubes(CNTs) functionalized with oxygen(OCNTs) and nitrogen(NCNTs) were employed for the oxygen evolution reaction(OER) in 0.1 M KOH.The catalysts were synthesized by metal-organic chemical vapor deposition using ruthenium carbonyl(Ru_3(CO)_(12)) as Ru precursor. The obtained RuO_2/OCNT and RuO_2/NCNT composites were characterized using TEM, H_2-TPR, XRD and XPS in order probe structure–activity correlations, particularly, the effect of the different surface functional groups on the electrochemical OER performance. The electrocatalytic activity and stability of the catalysts with mean RuO_2 particle sizes of 13–14 nm was evaluated by linear sweep voltammetry, cyclic voltammetry, and chronopotentiometry, showing that the generation of nitrogen-containing functional groups on CNTs was beneficial for both OER activity and stability. In the presence of RuO_2, carbon corrosion was found to be significantly less severe.     

Highly exposed NiFeOx nanoclusters supported on boron doped carbon nanotubes for electrocatalytic oxygen evolution reaction

The development of efficient and cost-effective electrocatalysts for oxygen evolution reaction (OER) is crucial for the overall water splitting. Herein, we prepared a highly exposed NiFeO_x ultra-small nanoclusters supported on boron-doped carbon nonotubes catalyst, which achieves a 10 mA/cm² anodic current density at a low overpotential of 213 mV and the Tafel slope of 52 mV/dec in 1.0 mol/L KOH, superior to the pristine NiFeO_x-CNTs and other state-of-the-art OER catalysts in alkaline media. A combination study (XPS, sXAS and XAFS) verifies that the local atomic structure of Ni and Fe atoms in the nanoclusters are similar to NiO and Fe₂O₃, respectively, and the B atoms which are doped into the crystal lattice of CNTs leads to the optimization of Ni 3d e_g orbitals. Furthermore, in-situ X-ray absorption spectroscopies reveal that the high valence state of Ni atoms are served as the real active sites. This work highlights that the precise control of highly exposed multicomponent nanocluster catalysts paves a new way for designing highly efficient catalysts at the atomic scale.     

A review on non-noble metal based electrocatalysis for the oxygen evolution reaction

In order to find a clean, efficient and sustainable new energy source that can replace fossil fuels, hydrogen energy is considered to be the most ideal choice. Electrocatalytic oxygen evolution plays a vital role in the development of hydrogen energy, promotes the research of new electrocatalysts, and is dedicated to find materials with high electrocatalytic efficiency. This article discusses in detail the major developments in OER electrocatalysts, including recently reported metal and non-metal based materials. Metal-based catalysts, although having the advantages of high catalytic activity, have disadvantages such as poor stability and low selectivity, which hinder the further application of such materials. Non-metallic based materials avoid such disadvantages and exhibit very substantial performance in overall water decomposition. This review provides useful knowledge of a well-designed OER electrocatalyst and a possible strategy for OER/HER dual-function catalytic performance for future development.     

pH-sensing properties of PbO<Subscript>2</Subscript> thin film electrodeposited on carbon ceramic electrode

In this paper, a new highly sensitive potentiometric pH electrode is proposed based on the solid-state PbO₂ film electrodeposited on carbon ceramic electrode (CCE). Two different crystal structures of PbO₂, α and β were examined and the similar results were obtained. Moreover, the experimental results obtained for the proposed pH sensor and a conventional glass pH electrode were in good agreement. The electromotive force (emf) signal between the pH-sensitive PbO₂-coated CCE and SCE reference electrode was linear over the pH range of 1.5–12.5. Near-Nernstian slopes of −64.82 and −57.85 mV/pH unit were obtained for α- and β-PbO₂ electrodes, respectively. The interferences of some mono-valence and multi-valence ions on potentiometric response of the sensor were studied. The proposed pH sensor displayed high ion selectivity with respect to K⁺, Na⁺, Ca²⁺, and Li⁺, with log values around −12 and has a working lifetime of about 30 days. Key parameters important for the pH sensor performance, including kind of PbO₂ film, selectivity, response time, stability, and reproducibility, have been characterized. The proposed electrode showed a good efficiency for direct pH-metry after calibration and pH-metric titrations without calibration step. The response time was about 1 s in acidic medium and less than 30 s in alkaline solutions. The pH values of complex matrix samples such as fruit juices measured by the proposed sensor and a conventional glass pH electrode were in good agreement.