Analysis of suitability of TPP ash-slag waste as materials for hydrogen fuel storage

The current trends in energy were described, the main of which is the use of alternative energy sources, especially hydrogen. The most common methods of hydrogen accumulation were proposed: accumulation of compressed gaseous hydrogen in high-pressure tanks; accumulation of liquid hydrogen in cryogenic tanks; storing hydrogen in a chemically bound state; accumulation of gaseous hydrogen in carriers with a high specific surface area. Based on the combination of advantages and disadvantages, the most promising methods of accumulation were selected: storage of liquid hydrogen and storage of hydrogen in carriers with a high specific surface area. The main requirement for materials for hydrogen storage by these methods was revealed – a high specific surface area. Prospects for the development of waste-free low-emission technologies due to the recycling of secondary raw materials and the development of low-temperature technologies for the synthesis of functional and structural materials were substantiated. The applicability of large-scale ash and slag waste from coal-fired thermal power plants as a raw material for obtaining materials by low-temperature technologies was shown. The traditional ways of using ash and slag waste as a raw material, active additive and filler in the production of cements were described. Modern technologies for the production of innovative materials with a unique set of properties were presented, namely carbon nanotubes, silica aerogel and geopolymer materials. The prospect of using geopolymer matrices as a precursor for the synthesis of a number of materials was described; the most promising type of materials was selected – geopolymer foams, which are mainly used as sorbents for purifying liquids and gases or accumulating target products, as well as heat-insulating materials. The possibility of obtaining products of any shape and size on the basis of geopolymer matrices without high-temperature processing was shown. The special efficiency of the development of the technology of porous granules and powders obtained from a geopolymer precursor using various methods was substantiated. The obtained granules can be used in the following hydrogen storage technologies: direct accumulation of hydrogen in porous granules; creation of insulating layers for liquid hydrogen storage units.     

“自动控制系统工程设计”课程思政教学实践

学习不仅仅是自然科学知识的学习，更是社会科学、民族文化、正确人生观和价值观的形成过程，“课程思政”无疑正是实现该目标的捷径，它是当前高等院校思想政治教育的新模式。如何提升学生解决“复杂工程问题”的能力成为高校开展工程教育和“新工科”的难点和重点，而课程思政正是培养学生解决“复杂工程问题”中所需要的非技术因素的重要途径。“自动控制系统工程设计”是自动化专业高年级学生的一门专业课，当前关于“课程思政”的论述是指导思想居多、实施经验以及案例设计较少，针对该问题以“自动控制系统工程设计”为例，详细给出了“课程思政”教学案例的具体实施过程，对同类课程提供参考。     

The role of carbon in microstructure evolution of SiBCO ceramics

The composition of polymer derived ceramics could be readily tuned through controlling the structure and element content of the polymer precursors, and investigation on the effect of the element on microstructure evolution is important to the design of advanced ceramics. In this article, the effect of carbon content in SiBCO polymer precursors was systematically investigated. The polymer network and thermal stability of polymer precursors and the carbon content of pyrolyzed SiBCO ceramic could be readily tuned by controlling the DVB amount used. Carbon contributed to the formation of graphitic carbon in SiBC_xO ceramics and inhibited the growth of β–SiC and SiO₂ crystals at 1600 °C, but lead to an increase in the graphitic carbon phase at 1800 °C.     

Amorphous-crystalline cobalt-molybdenum bimetallic phosphide heterostructured nanosheets as Janus electrocatalyst for efficient water splitting

Efficient and sustainable Janus catalysts toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are highly desirable for future hydrogen production via water electrolysis. Herein we report an active Janus electrocatalyst of amorphous-crystalline cobalt-molybdenum bimetallic phosphide heterostructured nanosheets on nickel foam (CoMoP/CoP/NF) for efficient electrolysis of alkaline water. As-reported CoMoP/CoP/NF consists of amorphous bimetal phosphide nanosheets doped with crystalline CoMoP/CoP heterostructured nanoparticles on NF. It can efficiently catalyze both HER (η = 127 mV@100 mA cm^?2) and OER (η = 308 mV@100 mA cm^?2) in alkaline electrolyte with long-term durability. Serving as anode and cathode of water electrolyzer, CoMoP/CoP/NF generates electrolytic current of 10, 50 and 100 mA cm^?2 at low voltage of 1.50, 1.59, and 1.67 V, respectively.     

Zeolitic-imidazolate frameworks-derived Co3S4/NiS@Ni foam heterostructure as highly efficient electrocatalyst for oxygen evolution reaction

Transition metals sulfide-based nanomaterials have recently received significant attention as a promising cathode electrode for the oxygen evolution reaction (OER) due to their easily tunable electronic, chemical, and physical properties. However, the poor electrical conductivity of metal-sulfide materials impedes their practical application in energy devices. Herein, firstly nano-sized crystals of cobalt-based zeolitic-imidazolate framework (Co-ZIF) arrays were fabricated on nickel-form (NF) as the sacrificial template by a facile solution method to enhance the electrical conductivity of the electrocatalyst. Then, the Co₃S₄/NiS@NF heterostructured arrays were synthesized by a simple hydrothermal route. The Co-ZIFs derived Co₃S₄ nanosheets are grown successfully on NiS nanorods during the hydrothermal sulfurization process. The bimetallic sulfide-based Co₃S₄/NiS@NF-12 electrocatalyst demonstrated a very low overpotential of 119 mV at 10 mA cm^?2 for OER, which is much lower than that of mono-metal sulfide NiS@NF (201 mV) and ruthenium-oxide (RuO₂) on NF (440 mV) electrocatalysts. Furthermore, the Co₃S₄/NiS@NF-12 electrocatalyst showed high stability during cyclic voltammetry and chronoamperometry measurements. This research work offers an effective strategy for fabricating high-performance non-precious OER electrocatalysts.     

Density functional theory study of the hydrogen evolution reaction in haeckelite boron nitride quantum dots

To satisfy arising energy needs and to handle the forthcoming worldwide climate transformation, the major research attention has been drawn to environmentally friendly, renewable and abundant energy resources. Hydrogen plays an ideal and significant role is such resources, due to its non-carbon based energy and production through clean energy. In this work, we have explored catalytic activity of a newly predicted haeckelite boron nitride quantum dot (haeck-BNQD), constructed from the infinite BN sheet, for its utilization in hydrogen production. Density functional theory calculations are employed to investigate geometry optimization, electronic and adsorption mechanism of haeck-BNQD using Gaussian16 package, employing the hybrid B3LYP and wB97XD functionals, along with 6–31G(d,p) basis set. A number of physical quantities such as HOMO/LUMO energies, density of states, hydrogen atom adsorption energies, Mulliken populations, Gibbs free energy, work functions, overpotentials, etc., have been computed and analysed in the context of the catalytic performance of haeck-BNQD for the hydrogen-evolution reaction (HER). Based on our calculations, we predict that the best catalytic performance will be obtained for H adsorption on top of the squares or the octagons of haeck-BNQD. We hope that our prediction of most active catalytic sites on haeck-BNQD for HER will be put to test in future experiments.     

Porous CoNiOOH nanosheets derived from the well-mixed MOFs as stable and highly efficient electrocatalysts for water oxidation

The development of efficient and stable electrocatalysts is of great significance for improving water splitting. Among them, transition metal oxyhydroxides show excellent performance in oxygen evolution reactions (OER), but there are certain difficulties in direct preparation. Recently, Metal–organic frameworks (MOFs) as precatalysts or precursors have shown promising catalytic performance in OER and can be decomposed under alkaline conditions. Therefore, using a mild and controllable way to convert MOFs into oxyhydroxides and retaining the original structural advantages is crucial for improving the catalytic activity. Herein, a rapid electrochemical strategy is used to activate well-mixed MOFs to prepare Co/Ni oxyhydroxide nanosheets for efficient OER catalysts, and the structural transformation in this process was investigated in detail by using scanning electron microscope, X-ray diffraction, Raman, X-ray photoelectron spectroscopy and electrochemical methods. It is discovered that electrochemical activation can promote ligand substitution of well-mixed MOFs to form porous oxyhydroxide nanosheets and tune the electronic structure of the metal (Co and Ni), which can lead to more active site exposure and accelerate charge transfer. In addition, the change of structure also improves hydrophilicity, as well as benefiting from the strong synergistic effect between multiple species, the optimal a-MCoNi–MOF/NF has excellent OER performance and long-term stability. More obviously, the porous CoNiOOH nanosheets are formed in situ during electrochemical activation process through structural transformation and acts as the active centers. This work provides new insights for mild synthesis of MOFs derivatives and also provides ideas for the preparation of highly efficient catalysts.     

Self-construction of pea-like Cu/Cu2S Mott-Schottky electrocatalyst for the oxygen evolution reaction

The speed of the oxygen evolution reaction seriously affects the hydrogen production efficiency of water electrolysis. Hence it is crucial to develop efficient and durable OER electrocatalysts. Construction of heterojunction catalysts is also one of the strategies to develop efficient catalysts. In this paper, a pea-like Cu/Cu₂S–C3 Mott?Schottky electrocatalyst was self-constructed by vapor deposition, while CF (copper foam) was used as substrate material and copper source, and thiourea was served as sulfur source. The built-in electric field is formed at the metal-semiconductor interface, which endows it with promising electrocatalytic performance. As the working electrode, the overpotentials of Cu/Cu₂S–C3 required to reach the current density of 10 and 50 mA cm^?2 were about 170 and 335 mV. The impact of the Mott-Schottky structure on the catalyst was also reflected in stability. The i-t tests of the sample Cu/Cu₂S–C3 were carried out under 10 and 60 mA cm^?2 and performed well.     

Recent insights in synthesis and energy storage applications of porous carbon derived from biomass waste: A review

In the last few decades, global warming, environmental pollution, and an energy shortage of fossil fuel may cause a severe economic crisis and health threats. Storage, conversion, and application of regenerable and dispersive energy would be a promising solution to release this crisis. The development of porous carbon materials from regenerated biomass are competent methods to store energy with high performance and limited environmental damages. In this regard, bio-carbon with abundant surface functional groups and an easily tunable three-dimensional porous structure may be a potential candidate as a sustainable and green carbon material. Up to now, although some literature has screened the biomass source, reaction temperature, and activator dosage during thermochemical synthesis, a comprehensive evaluation and a detailed discussion of the relationship between raw materials, preparation methods, and the structural and chemical properties of carbon materials are still lacking. Hence, in this review, we first assess the recent advancements in carbonization and activation process of biomass with different compositions and the activity performance in various energy storage applications including supercapacitors, lithium-ion batteries, and hydrogen storage, highlighting the mechanisms and open questions in current energy society. After that, the connections between preparation methods and porous carbon properties including specific surface area, pore volume, and surface chemistry are reviewed in detail. Importantly, we discuss the relationship between the pore structure of prepared porous carbon with surface functional groups, and the energy storage performance in various energy storage fields for different biomass sources and thermal conversion methods. Finally, the conclusion and prospective are concluded to give an outlook for the development of biomass carbon materials, and energy storage applications technologies. This review demonstrates significant potentials for energy applications of biomass materials, and it is expected to inspire new discoveries to promote practical applications of biomass materials in more energy storage and conversion fields.     

Polymer electrets and their applications

Polymer electrets have revealed great potential application in electromechanical devices because of the low weight, large quasi-piezoelectric sensitivity, and excellent flexibility. For an electret, a permanent and macroscopic electric field exists on the surface, principally led by a macroscopic electrostatic charge on the surface or a net orientation of polar groups inside the object. Here, progress in the development of polymer electrets is reviewed. After a brief retrospect of the research courses and those typical polymer electrets that are classified into fluorine polymer and nonfluorine polymer, we present a survey on the charging methods, including corona, soft X-ray, contact, thermal and monoenergetic particle beams. The latest representative applications (i.e., power harvesting, sensors, field effect transistors, and biomedicine) based on polymer electrets are also summarized. Finally, we complete this review with a discussion on perspectives and challenges in this field.