N,P, S co-doped biomass-derived hierarchical porous carbon through simple phosphoric acid-assisted activation for high-performance electrochemical energy storage

Porous carbon materials are the most widely used electrode materials in Electric Double Layer Supercapacitor (EDLS). Optimize specific surface area, improving hierarchical pores structure, and doping heteroatoms are all important methods to improve the capacitance performance of electrodes. Herein, we synthesize walnut shell-derived hierarchical porous carbon (WSPC) with cost-effective and well-developed pore for electrochemical energy storage via simple phosphoric acid-assisted activation method. The final porous carbon products have perfect microporous structure, abundant heteroatom functional groups (the atomic content ratio of nitrogen, phosphorus and sulfur reaches 10.3%), and high specific surface area and pore volume (up to 2583 m² g^?1 and 1.236 cm³ g^?1, respectively). In the three-system, the electrode shows an optimal specific capacitance of up to 332 F g^?1 and excellent rate performance. In the symmetric system, the symmetric device WSPC//WSPC shows a maximum gravimetric specific energy of ~14.08 Wh kg^?1. And the device still has a specific energy of 9.75 Wh kg^?1 even under the high gravimetric specific power of 7 kW kg^?1. In addition, the device has excellent cycle stability and retains an initial specific capacitance of 90.2% after 8000 galvanostatic charge-discharge (GCD) cycle. In summary, these outstanding results suggest the biomass derived porous carbon possessing the potential and will show great commercial value for the fabrication of high performance supercapacitors.     

Mechanism for electrochemical hydrogen insertion in carbonaceous materials

The mechanism for safe and reversible storage of hydrogen in porous carbonaceous materials by electrochemical decomposition of water in alkaline electrolyte is proposed. Atomic H was found to be inserted into the microdomains of defective graphene layers. Hydrogen storage capacity increases with increasing interlayer distance between carbon sheets. Hydrogen insertion in carbonaceous materials occurs at ambient conditions. Static potential acts as an electrochemical valve which can retain the hydrogen in the carbon structure, thus preventing leakage during storage.     

Melaleuca bark based porous carbons for hydrogen storage

Typical porous carbons were obtained from waster biomass, melaleuca bark activated by potassium hydroxide (KOH), and characterized by XRD, SEM, TEM, FTIR, XPS and N₂-sorption. The different samples with tunable morphologies and texture were prepared by controlling synthesis reaction parameters. The resulting samples demonstrate both high surface area (up to 3170 m² g⁻¹) and large hydrogen storage capacity (4.08 wt% at 77 K and 10 bar), implying their great potential as hydrogen storage materials.     

Degradation of biomass components to prepare porous carbon for exceptional hydrogen storage capacity

Porous carbon has been constructed in various strategies for hydrogen storage. In this work, a simple-effective strategy was proposed to transform sustainable biomass into porous carbon by degrade partial lignin and hemicellulose with Na₂SO₃ and NaOH aqueous mixture. This method collapses the biomass structure to provide more active sites, and also avoid the generation and accumulation of non-porous carbon nanosheets. As a result, the as-prepared sample possesses high specific surface area (2849 m² g^?1) and large pore volume (1.08 cm³ g^?1) concentrating almost completely on micropore. Benefit to these characteristics, the as-prepared sample exhibits appealing hydrogen storage capacity of 3.01 wt% at 77 K, 1 bar and 0.85 wt% at 298 K, 50 bar. The isosteric heat of hydrogen adsorption is as high as 8.0 kJ mol^?1, which is superior to the most biochars. This strategy is of great significance to the conversion of biomass and the preparation of high-performance hydrogen storage materials.     

Perspective and potential of CO2: A focus on potentials for renewable energy conversion in the Mediterranean basin

Figures commonly quoted on the soon shortage of generating energy from fossil sources which may give the impression that it will be possible to switch to renewable energies conversion as foundations for the future of industrial instances in the Mediterranean basin. In this study, CO₂ energy potential and perspectives in the Mediterranean basin have been investigated in terms of efficiency, feasibility, geographical patterns and savings. Two conjoint mathematical protocols have been carried out in order to yield a simplified extracted scheme for prototype CO₂ trapping/storage plants.     

生物质能的现状和可持续性发展

阐述了发展生物质能源的必然性,在不同的国家生物质能源的利用情况下,主要介绍了中国发展利用生物质能源的现状和生物质能源在中国的重要战略意义。     

One-step synthesis of 3D sulfur-doped porous carbon with multilevel pore structure for high-rate supercapacitors

In this work, three-dimensional (3D) interconnected S-doped porous carbon materials are fabricated using bio-waste sodium lignosulfonate as carbon and sulfur precursor by in situ carbonization and subsequent KOH activation process. The as-obtained S-PC-50 has high specific surface area of 1592 m² g^?1, high S weight percentage up to 5.2 wt% and interconnected porous framework consisting of micro-, meso- and macropores. As a result, the S-PC-50 exhibits a high specific capacitance of 320 F g^?1 at 0.2 A g^?1, excellent rate performance with 76.5% capacitance retention after a current density increasing from 2 A g^?1 (200 F g^?1) to 100 A g^?1 (153 F g^?1) and 99% capacitance retention after 10,000 cycles at 5 A g^?1. Besides, the symmetric supercapacitor can deliver a high energy density up to 8.2 Wh kg^?1 at 50 W kg^?1.     

Sodium alginate assisted preparation of oxygen-doped microporous carbons with enhanced electrochemical energy storage and hydrogen uptake

Microporous carbons with large oxygen content have been successful synthesized from biomass by the sodium alginate assisted strategy. During the activation process, the Na₂O formed by the decomposition of sodium alginate combines with the activator KOH to undergo a redox reaction in situ with precursor, thereby forming a rich porosity in the samples. The obtained samples possess not only high SSA (2310~3001 m² g^?1) and large pore volume (0.89~1.19 cm³ g^?1) arising almost completely (>90%) from micropores, but also retains a high content of oxygen (21.86~32.47 wt %). As supercapacitor electrodes, the oxygen-doped microporous carbons display a high specific capacitance of 385 F g^?1 at 0.5 A g^?1 with capacity stability of 91.5% after 20 000 cycles at 5 A g^?1. As hydrogen storage materials, the oxygen-doped microporous carbons exhibit enhanced hydrogen storage capacity of 2.84 wt% (77 K, 1 bar) and 0.91 wt% (303 K, 50 bar). Experimental data indicate that this work provides a simple-efficient and universal strategy for preparing oxygen-doped microporous carbon for high-performance energy and hydrogen storage.     

关于发展节能环保产业的几点思考

能源和环境是人类生存和发展的重要基础。加快节能环保产业的发展,有助于推动经济平稳较快和可持续发展。     

Doping of nitrogen into biomass-derived porous carbon with large surface area using N2 non-thermal plasma technique for high-performance supercapacitor

A novel and facile modified method using non-thermal plasma is proposed to insert N active sites into biomass-derived porous carbon as high-performance electrode materials for supercapacitor. Large surface areas up to 3040.3 and 2662.5 m²/g with mesopore-dominant hierarchical porous carbons are produced from biomass of lilac and lotus seedpods via KOH activation, respectively. The lilac and lotus seedpods derived porous carbon electrodes present good specific capacitances of 214.5 and 201.1 F/g, respectively. N₂ non-thermal plasma modification successfully increases N-containing groups on lilac and lotus seedpods derived porous carbons, where the corresponding N atomic contents are increased by 10.2 and 3.6 times, respectively. As supercapacitor electrodes, their specific capacitances are improved greatly after plasma modification and up to 342.5 F/g (increased by 59.7%) and to 332.1 F/g (increased by 65.2%) at 0.5 A/g in 6 M KOH electrolyte with excellent cycling stability of 85.2% and 95.4% at 10 A/g after 5000 cycles, respectively.     

Non-azeotropic mixture energy conversion

The thermodynamic performance of an energy conversion device may be improved potentially by using a non-azeotropic mixture in a vapor cycle. A non-azeotropic mixture has a temperature distribution parallel to that of the surrounding fluid with which heat transfer takes place during the evaporation and condensation processes. The non-azeotropic mixture vapor cycle is investigated theoretically in this paper, and energy savings of such an energy conversion cycle are predicted.     

Sustainable development of the Belgrade energy system

Cities are the most important energy consumers of any country in all energy vector components. Nowadays, Belgrade as a cultural, educational, scientific, administrative, political, and business center of the region with its own structure of production, transportation, services, and urban system, represents significant consumer of different energy forms. Only useful and final energy is delivered to energy consuming sectors of a city. Simulation model MAED was used in this paper to estimate energy demand in city for a long time period. On the basis of energy demand forecast for three major ‘energy consumers’ (sectors of household/service, industry, and transportation) until 2020, the sustainable development ‘scenarios’ of Belgrade energy system are developed (2005–2010, 2010–2015, 2015–2020). For each ‘scenario’, the energy systems of primary resources are determined so to satisfy the predicted differences in energy consumption for the mentioned time intervals until 2020. In this case different ‘scenarios’ are evaluated. The evaluation of ‘scenarios’ sustainability is obtained by method of multi-criteria analysis. Using energy indices for sustainable development, the following indices are taken into consideration for the assessment of scenario sustainability: economical, social, and environmental. The obtained results can be used by experts in decision-making process.     

Biomass conversion: An overview of the IEA bioenergy agreement task VII

Extensive research and development activities have been conducted in the area of biomass conversion over the past several years. Task VII of the International Energy Agency's Bioenergy Agreement provided a means to coordinate the ongoing national programs of fourteen participating countries during the period from 1989 through 1991. This paper provides an overview of the state of the technology development for biomass conversion and summarizes the progress of the IEA program.     

An alternative energy source from palm wastes industry for Malaysia and Indonesia

Malaysia and Indonesia are the largest producers of palm oil product. The palm oil industry has contributed the biggest income to the countries for many years. Moreover, palm oils has emerged as one of the most important oils in the world’s oils and the market of fats. About 90% of palm oil is used as food related products worldwide, and the other 10% is used for basic raw material for soap. There are more than a hundred palm oil processing mills in the two countries. As such, a lot of savings can be done by using the fiber and shell from the processing wastes as an alternative fuel for electricity generation for this industry. This paper deals with energy conversion from the fiber and shell of the industry wastes as an alternative energy source for the palm oil mill industry in the two countries mentioned. The study concentrates on using the fiber and shell obtained from the processing of palm oil as fuels for the boiler instead of fossil fuel. In addition, the possibility of excess air and fuel air ratio for the fiber and shell combustion process is also discussed. Furthermore, it has been found that the shell and fiber alone can supply more steam and electricity than is required. Some palm oil mills in Malaysia and Indonesia have applied this strategy successfully. The FELDA palm oil mill, with the capacity 30–60 tons FFB/h, in Sungai Tengi, Selangor, Malaysia has been selected for this research.     

Fabrication of high-power electric double-layer capacitors

The electrochemical behavior of activated carbon/carbon (AC/C) composite electrodes was investigated for high-power electric doublelayer capacitors (EDLCs). It was found that high-rate charge/discharge characteristics are affected by the resistance of the electrolyte phase in the pores of the electrode. The charge/discharge characteristics were improved by optimizing the pore-size distribution of the electrodes. The size and total volume of the macro-pores in the electrodes were controlled by mixing and burning out polymer spheres. A high-power EDLC (15V, 470 F), which can discharge as much as 500 A, was fabricated by using improved AC/C composite electrodes.     

Sustainable development and global security

The sustainable development paradigm demands that we leave to future generations at least the same or better possibilities for development as they exist today. This requires a balanced development of economy, society and environment, and the absence of wars and terrorism. Wars and terror attacks are causing grave damage to the development, including loss of human lives, destruction of property, decrease in economic activity, threatened individual freedoms, and destruction of natural environment. It is therefore very important for sustainability to establish a secure global environment. This requires both protection against violence and elimination of its root causes, as well as active work of individuals, national states, non-governmental and international organisations toward peace.     

制度创新推进新能源产业可持续发展

要保持新能源的开发始终在技术创新下不断有所发现有所进步,必须坚持制度创新,与时俱进创新新能源发展的体制和机制。《可再生能源法》中的某些制度设计既不完善也不清晰、明确,应适时地把其从单纯促进开发的法律,改变为有序、规范开发和有效利用的一部法律。与新能源开发有直接关系的《电力法》和《节约能源法》,在规划、结构、布局、网络建设及价格和财税等方面,需要建立新的调整关系和法律的规范制度。