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AbstractChina is under pressure to improve its agricultural productivity to keep up with the demands of a growing population with increasingly resource‐intensive diets. This productivity improvement must occur against a backdrop of carbon intensity reduction targets, and a highly fragmented, nutrient‐inefficient farming system. Moreover, the Chinese government increasingly recognizes the need to rationalize the management of the 800 million tonnes of agricultural crop straw that China produces each year, up to 40% of which is burned in‐field as a waste. Biochar produced from these residues and applied to land could contribute to China's agricultural productivity, resource use efficiency and carbon reduction goals. However competing uses for China's straw residues are rapidly emerging, particularly from bioenergy generation. Therefore it is important to understand the relative economic viability and carbon abatement potential of directing agricultural residues to biochar rather than bioenergy. Using cost‐benefit analysis (CBA) and life‐cycle analysis (LCA), this paper therefore compares the economic viability and carbon abatement potential of biochar production via pyrolysis, with that of bioenergy production via briquetting and gasification. Straw reincorporation and in‐field straw burning are used as baseline scenarios. We find that briquetting straw for heat energy is the most cost‐effective carbon abatement technology, requiring a subsidy of $7 MgCO2e−1 abated. However China's current bioelectricity subsidy scheme makes gasification (NPV $12.6 million) more financially attractive for investors than both briquetting (NPV $7.34 million), and pyrolysis ($−1.84 million). The direct carbon abatement potential of pyrolysis (1.06 MgCO2e per odt straw) is also lower than that of briquetting (1.35 MgCO2e per odt straw) and gasification (1.16 MgCO2e per odt straw). However indirect carbon abatement processes arising from biochar application could significantly improve the carbon abatement potential of the pyrolysis scenario. Likewise, increasing the agronomic value of biochar is essential for the pyrolysis scenario to compete as an economically viable, cost‐effective mitigation technology.

AbstractAnchoring groups are extremely important in controlling the performance of dye‐sensitized solar cells (DSCs). The design and characterization of sensitizers with new anchoring groups, in particular non‐carboxylic acid groups, has become a recent focus of DSC research. Herein, new donorπacceptor zincporphyrin dyes with a pyridine ring as an anchoring group have been designed and synthesized for applications in DSCs. Photophysical and electrochemical investigations demonstrated that the pyridine ring worked effectively as an anchoring group for the porphyrin sensitizers. DSCs that were based on these new porphyrins showed an overall power‐conversion efficiency of about 4.0 % under full sunlight (AM 1.5G, 100 mW cm−2).

We report the first flexible hybrid energy cell that is capable of simultaneously or individually harvesting thermal, mechanical, and solar energies to power some electronic devices. For having both the pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based nanogenerator (NG) was used to harvest thermal and mechanical energies. Using aligned ZnO nanowire arrays grown on the flexible polyester (PET) substrate, a ZnO-poly(3-hexylthiophene) (P3HT) heterojunction solar cell was designed for harvesting solar energy. By integrating the NGs and the solar cells, a hybrid energy cell was fabricated to simultaneously harvest three different types of energies. With the use of a Li-ion battery as the energy storage, the harvested energy can drive four red light-emitting diodes (LEDs).

Abstract The alternative energy plays a crucial role in the sustainable energy development. The alternative energy related literature had attracted a growing attention with the research outputs expanding substantially. Based on the Science Citation Index-Expanded (SCI-E) and the Social Sciences Citation Index (SSCI), a bibliometric analysis of the research output was carried out to depict existing research activities on alternative energy and future directions. The article was the main type of publications with the English as the dominate language to explain their results. With the publications increasing rapidly since 2008, the researches mostly focused on the fields of Energy & Fuels and Environmental Sciences. Energy Policy was the journal that published the largest number of research articles on the alternative energy. The bioenergy and solar energy were popular items in the commonly used 20 journals. Among the countries, the USA was leading on alternative energy related research, publishing the largest number of articles (TP=2368) and being the most influent ( h -index=90). The USA played a key role in the academic collaborations with China, UK, Canada, Germany, Italy, South Korea and Spain. The National Renewable Energy Lab (the USA) contributed most in the alternative energy field and more specially, the School of Electrical & Computer Engineering (TP=36) was the most productive subordinate in the National Technology University of Athens. It was interesting to note that more attention was paid to solar or wind energy during the first 5 or 10 years, then turned to bioenergy subsequently except for Spain, Canada and Australia. In addition, bioenergy received the most attention in the 7 types of alternative energy. The forest/wood biomass, energy crops and switchgrass were the main bioenergy resources and fermentation was the commonly used conversion technology. The production of biogas, biodiesel and bioethanol was most popular in the bioenergy related studies. Wind energy and solar energy related researches were mainly on the energy utilization approaches such as the wind generation, wind farm, photovoltaic and solar thermal. The conversion devices such as the wind turbine and solar cell were paid most attention in order to improve the production efficiency. The most cited article, published in Desalination in 2009 with 1562 citations until 2013, was about wind power utilization in the reverse osmosis desalination plant.

Abstract Energy consumption in the household sector has become an important issue in China's energy consumption and an important unit of China's clean energy transformation. Currently, the potential air pollution, carbon emissions and health risks caused by energy consumption in many areas cannot be ignored, and refined and regionalized index-based research data necessary to support decision making are lacking. Based on household-level survey data collected from Qinghai Province, China, we estimated greenhouse gas (GHG) and air pollutant emissions from spatial perspectives, including household energy consumption in pastoral, agropastoral, and agricultural zones. The findings suggest that the total annual GHG and pollutant emissions per capita in the area was 2296.32 kg per year. The highest amount of pollutants was emitted from the pastoral zones, followed by the agropastoral and agricultural zones. CO2 is the primary GHG emitted by household energy consumption. Dung burning was the cause of the high PM2.5 emissions in the pastoral areas, while the use of coal was the primary cause of GHG and pollutant emissions in the agropastoral and agricultural zones. These findings highlight the need to integrate household energy policies with rural development to enable a complete transition towards cleaner fuels.

A self-humidifying composite membrane based on Nafion (R) hybrid with SiO2 supported sulfated zirconia particles (SiO2-SZ) was fabricated and investigated for fuel cell applications. The bi-functional SiO2-SZ particles, possessing hygroscopic property and high proton conductivity, were homemade and as the additive incorporated into our composite membrane. X-ray diffraction (XRD) and Fourier infrared spectrum (FT-IR) techniques were employed to characterize the structure of SiO2-SZ particles. Scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS) measurements were conducted to study the morphology of composite membrane. To verify the advantages of Nafion (R)/SiO2-SZ composite membrane, the IEC value, water uptake, proton conductivity, single cell performance and areal resistance were compared with Nafion (R)/SiO2 membrane and recast Nafion (R) membrane. The single cell employing our Nafion (R)/SiO2-SZ membrane exhibited the highest peak power density of 0.98 Wcm(-2) under dry operation condition in comparison with 0.74 Wcm(-2) of Nafion (R)/SiO2 membrane and 0.64 Wcm(-2) of recast Nafion (R) membrane, respectively. The improved performance was attributed to the introduction of SiO2-SZ particles, whose high proton conductivity and good water adsorbing/retaining function under dry operation condition, could facilitate proton transfer and water balance in the membrane. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.

AbstractCuO microspheres are obtained from thermal oxidation of Cu2O microspheres. A facile approach directed by electrostatic self‐assembly is used to fabricate graphene oxide wrapped CuO (CuO@GO). GO nanosheets directly used in batteries could reduce the preparation cost and pollution relative to reduced graphene oxide. As coating layers, GO could be electrochemically reduced to graphene in situ to obtain an additional 3D conductive network. The CuO@GO core–shell micro/nanocomposites exhibit significantly improved lithium storage capacity and cycling performance as compared to CuO microspheres or the physical mixture of CuO microspheres and GO nanosheets (CuO–GO‐PM). Under a current density of 100 mA g−1, CuO@GO retains a high discharge capacity of approximately 590 mAh g−1 for up to 50 cycles. After 200 cycles at a current density of 1000 mA g−1, the discharge capacity of the CuO@GO is approximately 313 mAh g−1, which is approximately 3 times larger than that of the CuO microspheres and CuO–GO‐PM.

Osmotic energy stored between seawater and freshwater is a clean and renewable energy source. However, developing high-efficiency and durable permselective membranes for harvesting osmotic energy remains a longstanding bottleneck. Herein, we report that a nanocomposite membrane with a biological serosa-mimetic structure can achieve high-performance osmotic energy generation through the coupling of two-dimensional (2D) sulfonated covalent organic framework (COF) nanosheets and anion-grafted aramid nanofibers (ANFs). As verified by theoretical calculations and experimental investigations, the 2D COF nanosheets not only provide abundant one-dimensional (1D)/2D nanofluidic channels to synergistically benefit an ultrafast ion migration but also enable high cation permselectivity via the covalently tethered anions. The grafted ANFs increase the mechanical strength of the membrane and further improve the ion diffusion/rectification. When it was applied in an osmotic power generator, the biomimetic membrane delivered a power density of 9.6 W m-2, far surpassing the commercial benchmark of 5.0 W m-2. This work could boost the viability of osmotic energy conversion toward a sustainable future.