Electron donors are widely exploited in visible-light photocatalytic hydrogen production. As a typical electron donor pair and often the first choice for hydrogen production, the sodium sulfide-sodium sulfite pair has been extensively used. However, the resultant thiosulfate ions consume the photogenerated electrons to form an undesirable pseudocyclic electron transfer pathway during the photocatalytic process, strongly limiting the solar energy conversion efficiency. Here, we report novel and bioinspired electron donor pairs offering a noncyclic electron transfer pathway that provides more electrons without the consumption of the photogenerated electrons. Compared to the state-of-the-art electron donor pair Na2S-Na2SO3, these novel Na2S-NaH2PO2 and Na2S-NaNO2 electron donor pairs enable an unprecedented enhancement of up to 370% and 140% for average photocatalytic H-2 production over commercial CdS nanoparticles, and they are versatile for a large series of photocatalysts for visible-light water splitting. The discovery of these novel electron donor pairs can lead to a revolution in photocatalysis and is of great significance for industrial visible-light-driven H-2 production. [GRAPHICS] .

针对大学生实践能力培养与"新工科"建设要求不适应等现象,通过金相技能大赛为抓手推动大学生实践教育改革和发展.金相技能大赛在重视理论结合实践,强化金相技能训练;全面锻炼学生综合素质;磨炼心性培养集体主义精神以及保障教育机会公平性方面具有积极影响.全国大学生金相技能大赛对培养大学生工匠精神,提高实践教育教学质量具有重要意义.

Focusing on the fundamental task of moral education,this article takes the"Raman Spectroscopy Analysis Experiment"course as a carrier to promote the ideological and political affinity of the experimental course.By exploring the ideological and political elements in the experimental contents and using various teaching methods flexibly,the students'enthusiasm for learning is motivated.Ultimately,value shaping and scientific literacy are integrated naturally with experimental theoretical knowledge and operational skills,enhancing the effectiveness of ideological and political education in materials science experimental courses.

Fe3O4/CNT composites are synthesized with ethylene glycol as solvent by a one-step solvothermal method and used as anode materials for asymmetric supercapacitors (ASC). An appropriate amount of water in ethylene glycol can accelerate the formation of Fe3O4 and reduce the average size of Fe3O4 to around 20 nm. However, spherical Fe3O4 particles larger than 100 nm will form in pure ethylene glycol for long reaction time. The Fe3O4/CNT composite with small Fe3O4 nanoparticles exhibits a high specific surface area, promoted electron transfer ability, as well as a high utilization rate of active materials. The optimized electrode shows a high specific capacity of 689 C g(-1) at 1 A g-1, and remains 443 C g(-1) at 10 A g(-1). The inferior long-term cycling stability is due to the phase transition of Fe3O4 and a reductive effect to form metallic Fe. An ASC using Fe3O4/CNT and NiCoO2/C composites as anode and cathode, respectively, delivers a high energy density of 58.1 Wh kg(-1) at a power density of 1007 W kg-1 in a voltage window of 1.67 V and has a capacity retention of 63% after 5000 cycles. The self-discharge behavior of the ASC is also investigated.

The performances of energy storage devices are strongly dependent on the electrode materials. Owing to the high theoretical capacity, NiCoO2 is a promising transition metal oxide for supercapacitors. Despite many efforts have been devoted, it still lacks of effective methods to overcome its shortcomings such as low conductivity and poor stability, in order to achieve its theoretical capacity. Herein, utilizing the thermal reducibility of trisodium citrate and its hydrolyzate, a series of NiCoO2@NiCo/CNT ternary composites in which NiCoO2@NiCo core-shell nanospheres deposited on CNT surface with adjustable metal contents are synthesized. Benefiting from the enhanced synergistic effect of both metallic core and CNTs, the optimized composite exhibits an extremely high specific capacitance (2660 F g-1 at 1 A g-1, the effective specific capacitance of the loaded metal oxide is 4199 F g-1, close to the theoretical value), an excellent rate performance and stability, when the metal content is about 37%. After depolarized calculation, the energy storage mechanism of the composite is reasonably analyzed. By controlling the contents of hexamethylenetetramine, trisodium citrate and CNTs in the reactant, the roles of them are distinguished. This study reveals an efficient novel strategy for transition metal oxides to maximize the electrochemical performances.

For rapid charge/discharge application, capacitive energy storage technology is an attractive approach. The low energy density, one of disadvantages, can be ameliorated by promising pseudocapacitive materials that harvest energy through redox reactions. In this work, a composite of bimetal oxide and carbon nanotubes (CNTs), NiCoO2@CNT, with a novel mesoporous grape-like structure is prepared by a mild method, in which metal oxide nanoparticles are bonded to CNTs like vines tightly. Due to the synergistic effect and the unique structure as well as the facilitation of CNTs, impressive properties are performed for the NiCoO2@CNT composite. With an excellent stability and rate capability, it achieves 1587 F g(-1) at 1 A g(-1). As revealed in the charge storage mechanism, the surface-controlled process plays a dominant role, which can be ascribed to the large proportion of redox reactions on the surface of small NiCoO2 nanoparticles and the presence of CNTs. NiCoO2@CNT and activated carbon are then applied to fabricate an asymmetric supercapacitor. It exhibits a high energy density of 41.8 Wh kg(-1) at 412 W kg(-1) and an outstanding cycling property with 92% maintained after 5000 cycles, indicating a great potential for the actual application. (C) 2021 Elsevier Ltd. All rights reserved.

为了主动适应新时代高等教育要求和高素质人才培养目标,提高材料专业本科毕业生的工程实践与创新能力,浙江大学材料科学与工程专业探索构筑了面向实践创新能力持续培养的多层次、递进式"3+3+3+1"实践教学体系,引入材料学科前沿交叉的自主探究性实验科目和O2O混合式实验教学等方法,以课外训练与课堂教学有机结合.实施名师引领的大学四年全程式创新能力持续贯通培养,突出强化学生的工程实践能力、科技创新能力和科学探索精神,形成特色鲜明的实践教学培养模式,为材料科学与工程专业的实践教学改革提供了借鉴.

Hollow hierarchical Mn–Co–P nanoarrays with high-efficiency and good-durability is a promising bifunctional electrocatalyst in overall water splitting.

Designing optimized nano-sized architecture is a promising approach to prepare high-performance elec-trode materials for supercapacitors. In this work, a hierarchical multi-shelled structure has been success-fully synthesized, which consists of a 3D carbon nanofiber network as a supporting scaffold prepared by carbonization of aramid nanofiber aerogel, an intermediate polypyrrole (PPy) bonding layer and a NiCoO2 outer shell, just like a coaxial cable in the structure. The intermediate PPy layer facilitates the uniform deposition of NiCoO2 by providing more anchor sites, and enhances the electrical contact between carbon nanofiber network and NiCoO2 shell due to its high conductivity and good compatibility with two differ-ent substances. The synergistic effect of the hierarchical configuration endows the electrode material with a high specific capacitance of 1037 F g-1 at 1 A g-1 and excellent cycling stability (-89% of initial capacitance after 7000 cycles). Moreover, an asymmetric supercapacitor based on the composite and acti-vated carbon achieves a high energy density of 37.7 Wh kg-1 at a power density of 465 W kg-1 in 1.65 V. This work may provide a feasible strategy to design high-performance hybrid electrodes for energy stor-age devices.(c) 2022 Elsevier Inc. All rights reserved.

The shuttle effect and excessive volume change of the sulfur cathode severely impede the industrial implementation of Li-S batteries. It is still highly challenging to find an efficient way to suppress the shuttle effect and volume expansion. Here, we report, for the first time, an innovative atomic orbital hybridization concept to construct the hierarchical hollow sandwiched sulfur nanospheres with double-polyaniline layers as the cathode material for large-scale high-performance Li-S batteries. This hierarchically 3D, cross-linked and stable sulfur-polyaniline backbone with interconnected disulfide bonds provides a new type and strong intrinsic chemical confinement of sulfur owing to the atomic orbital hybridization of Li 2s, S 3p, C 2p and N 2p. Crucially, such atomic orbital hybridization of sulfur sandwiched in the double sulfur-polyaniline network is highly reversible during the discharge/charge process and can very efficiently suppress the shuttle effect and volume expansion, contributing to a very high capacity of 1142 mAh g-1 and an excellent stabilized capacity of 886 mAh g-1 at 0.2 C after 500 cycles with a suppressed volume expansion and an unprecedented electrode integrity. This innovative atomic orbital hybridization concept can be extended to the preparation of other electrode materials to eliminate the shuttle effect and volume expansion in battery technologies. The present work also provides a commercially viable and up-scalable cathode material based on this strong and highly reversible atomic orbital hybridation for large-scale high-performance Li-S batteries.

Angle-resolved XPS combined with argon ion etching was used to characterize the surface functional groups and the chemical structure of Ti3C2Tx MXene. Survey scanning obtained on the sample surface showed that the sample mainly contains C, O, Ti and F elements, and a little Al element. Analyzing the angle-resolved narrow scanning of these elements indicated that a layer of C and O atoms was adsorbed on the top surface of the sample, and there were many O or F related Ti bonds except Ti–C bond. XPS results obtained after argon ion etching indicated staggered distribution between C–Ti–C bond and O–Ti–C, F–Ti bond. It is confirmed that Ti atoms and C atoms were at the center layer of Ti3C2Tx MXene, while O atoms and F atoms were located at both the upper and lower surface of Ti3C2 layer acting as surface functional groups. The surface functional groups on the Ti3C2 layer were determined to include O2−, OH−, F− and O−–F−, among which F atoms could also desorb from Ti3C2Tx MXene easily. The schematic atomic structure of Ti3C2Tx MXene was derived from the analysis of XPS results, being consistent with theoretical chemical structure and other experimental reports. The results showed that angle-resolved XPS combing with argon ion etching is a good way to analysis 2D thin layer materials.

在新工科建设要求背景下,传统单一的线下实训与新冠肺炎疫情期间单一的线上调研实习存在各自的缺陷,探索适合后疫情时代线上调研与线下实训相结合的"横纵结合"本科生企业实习模式非常必要.这种兼具横向行业跨越宽度和纵向专业了解深度的本科生企业实习模式,能够有效提高学生的企业认知实习效果,有利于培养学生综合分析解决问题的能力及勇于创新的精神,也适用于其他工科专业.

Three-dimensional macroporous heterostructural Ni-Fe hydroxides with different mole ratio (NixFe(1−x)-PH) were prepared via a sol-gel process combined with phase separation, and the overall water splitting electrocatalytic activity of the resultant macroporous Ni-Fe hydroxides were investigated in detail. The as-prepared Ni-Fe hydroxide has cocontinuous skeletons and interconnected macropores with a narrow pore size distribution (~150 nm), and possesses outstanding electrocatalytic activity with an overpotential of 263 mV for oxygen evolution reaction (OER) and 175 mV for hydrogen evolution reaction (HER) at 10 mA·cm−2 in 1 M KOH, respectively. The Ni0.6Fe0.4-PH | | Ni0.6Fe0.4-PH has efficient overall water splitting performance with a cell voltage of 1.61 V at 10 mA·cm−2 and great stability. The fantastic macropore structure and strong synergistic effect between Ni-Fe hydroxides significantly reinforce the contact area between the electrocatalyst and electrolyte, and endow high electrocatalytic performance of bifunctional electrocatalysts.

This paper provides a controllable process to prepare stable and efficient water splitting electrocatalysts which can be applied to renewable energy storage and conversion.

Developing advanced electrochemical double-layer supercapacitors (EDLCs) with high energy density and capacitance can be realized by exploring the electrodes possessing large specific surface area and high electronic conductivity. Here, we fabricated rambutan-like activated carbon sphere/carbon nanotube (ACS/CNT) composites which can be used as electrode materials in EDLCs. Curved CNTs have a polycrystalline structure with tens of nanometers in diameter and hundreds of nanometers in length and are uniformly grown on the surface of the ACS. The unique three-dimensional (3D) microstructure contributes to the ideal electrochemical performance of composite electrodes by combining high specific surface area and superior electrical conductivity. The specific capacitance of the ACS/CNT composite is 180 F/g, which is over threefold that of the pristine ACS electrode at a current density of 2.5 A/g. ACS/CNT electrodes exhibit an excellent cyclical ability at 10 mV/s sweep rate in the working voltage range, and the capacitance retention is almost 80% after 1000 cycles. The preparation of 3D microstructure opens up a new way of designing electrodes with a 3D conductive network and lays the foundation for the development of lightweight energy storage supercapacitors.

NiCo2O4 is a promising electrode material for supercapacitors and it has been widely investigated. However, its low conductivity restricts the reaction kinetics. Combining it with carbon materials can efficiently overcome the issue. But, very limited research about the homogenous coatings of NiCo2O4 nanocrystals on carbon nanotubes (CNTs) is reported. In this work, thin nanosheets and small nanoparticles of NiCo2O4 densely coated on CNTs are synthesized by tuning the annealing time with a hybrid of metal hydroxide@CNTs as a pre-cursor. In the precursor, core shell structures are formed by conformally coating 2D metal hydroxides on CNTs. After annealing it at 300 degrees C for different time, NiCo2O4 nanosheets or nanoparticles are then obtained and the core shell structure is remained. Due to the reduced crystal size of NiCo2O4 and the high conductivity of CNTs, the composites have large specific capacitances, excellent rate performances, and good stability. The composite of NiCo2O4 nanoparticles on CNTs has a higher specific capacitance, about 1786 F g(-1) at 0.5 A g(-1), than the hybrid of NiCo2O4 nanosheets on CNTs due to their different morphologies. Using the composite as positive electrode and activated carbon as negative electrode, a hybrid capacitor cell can work in a voltage of 1.6 V, delivering an energy density of 32.5 Wh kg(-1) at 800 W kg(-1), showing a large potential for supercapacitors.

It is a preferred method by constructing core - shell structured composites with heterojunctions to enhance the charge transfer and improve electrochemical performances for supercapacitors. In this work, we prepare NiCo2O4@CoS electrode materials on nickel foam via coating n - type CoS on p - type NiCo2O4 to form heterojunctions. The composite shows a synergistic effect from each component and has abundant active sites, as well as outstanding reaction kinetics. Density functional theory (DFT) analysis reveals that the NiCo2O4@CoS composite exhibits higher electronic conductivity than any single component. The NiCo2O4@CoS electrode presents an outstanding capacitance of 1902.5F g(-1) at the current density of 1 A g(-1). A hybrid capacitor with NiCo2O4@CoS as the positive electrode and activated carbon as the negative electrode shows a high energy density of 32.91 Wh kg(-1) at the power density of 425 W kg(-1) and an excellent stability of 81.5% initial capacitance after 5000 cycles at 1 A g(-1). The conclusions indicate that the heterojunction of NiCo2O4@CoS can be a potential electrode for supercapacitors.

The composites of NiCo2O4 with unique structures are extensively explored as promising electrodes. In this work, core-shell structured nanowires anchored on nickel foam are synthesized by the hydrothermal synthesis of NiCo2O4 as core and subsequent electrodeposition of alpha-Co(OH)(2) as shell. The core-shell composites exhibit enhanced electrochemical performances ascribing to the synergistic reactions from both materials, showing higher specific capacitance than any single component. By changing the deposition time, the mass loading of alpha-Co(OH)(2) can be easily controlled. The electrochemical performances of the hybrid electrodes are diverse with the mass loading of Co(OH)(2). The optimized hybrid electrode with 3 mins electrodeposition exhibits the highest specific capacitance (1298 F g(-1) at 1 A g(-1)) among all electrodes. The redox reaction is a main contributor to the total specific capacitance through electrochemical kinetics analysis. An asymmetric supercapacitor assembled by the optimized material as positive electrode and activated carbon as negative electrode can achieve a relatively high energy density of 39.7 Wh kg(-1) at a power density of 387.5 W kg(-1) (at 0.5 A g(-1)) in a voltage of 1.55 V. (C) 2020 Elsevier Inc. All rights reserved.

针对传统的材料专业实验课程教学,特别是涉及大型仪器的实验课程,普遍存在的理论与实践脱节、实验步骤机械、实验过程不完整的问题,提出了线上线下相结合的实验课程教学模式.将教学理论资料、操作流程预先展示在课题网站,以辅助现场实践教学,使得学生可以灵活、主动安排实践前的理论知识学习,完整了解大型仪器实验不便在课堂上当场展示的部分,并可能在现场实验时进行自主思考,提高学生的学习热情和实践操作能力,有利于培养学生的创新能力.

•Core-shell structures with NiCo2O4 as core show high performances for supercapacitors.•The shell materials are comprehensively reviewed in this work.•The mass loading of shell materials and the shape of NiCo2O4 are important for performances.