Antimony-doped graphene nanoplatelets

Heteroatom doping into the graphitic frameworks have been intensively studied for the development of metal-free electrocatalysts. However, the choice of heteroatoms is limited to non-metallic elements and heteroatom-doped graphitic materials do not satisfy commercial demands in terms of cost and stability. Here we realize doping semimetal antimony (Sb) at the edges of graphene nanoplatelets (GnPs) via a simple mechanochemical reaction between pristine graphite and solid Sb. The covalent bonding of the metalloid Sb with the graphitic carbon is visualized using atomic-resolution transmission electron microscopy. The Sb-doped GnPs display zero loss of electrocatalytic activity for oxygen reduction reaction even after 100,000 cycles. Density functional theory calculations indicate that the multiple oxidation states (Sb3+ and Sb5+) of Sb are responsible for the unusual electrochemical stability. Sb-doped GnPs may provide new insights and practical methods for designing stable carbon-based electrocatalystsclose0

Current Status of Fabrication of Solid Oxide Fuel Cells for Emission-Free Energy Conversion

Solid oxide fuel cells (SOFCs) are promising energy conversion devices due to their environment friendly operation with relatively high efficiencies (\u3e60 %). High power densities and stability upon interruption of fuel supply are required to realize the applications of the SOFC technology. The two main approaches for SOFC fabrication, namely; co-sintering of powders and infiltration of catalytically active components into porous scaffolds are described. It is stressed that the fabrication technique determines the performance of the SOFCs. Co-sintering of powders allow achieving high power densities while infiltration technique yields SOFC that show no performance degradation upon fuel interruption

A perspective for reducing environmental impacts of mussel culture in Algeria

Purpose In Algeria, the Ministry of Fisheries and Halieutic Resources has designed a strategic plan for the development of marine aquaculture for the years 2015-2025, which aims at expanding the annual production of Mediterranean mussel from less than 150 metric tonnes year(-1) in 2013 to 7600 metric tonnes year(-1) in 2025. We used Life Cycle Assessment (LCA) for evaluating the environmental impact of suspended mussel culture in Algeria and suggest management practices which could reduce it.Methods In order to estimate the current and perspective impact of this industry, we (1) applied LCA to one of the few farms currently operating in Algeria and (2) investigated two management scenarios for the farms to be established in the future in the same coastal area. The first scenario (Comp_S) represents the continuity with the current situation, in which each farm is competing with the other ones and is therefore managing the production cycle independently. In the second scenario (Coop_S), mussel farms are grouped in an aquaculture management area and shared the same facilities for post-processing harvested mussels before sending them to the market. The midpoint-based CML-IA method baseline 2000 V 3.01 was employed using SimaPro software. Furthermore, we carried out a Monte Carlo simulation, in order to assess the uncertainty in the results.Results and discussion The analysis focused on impact categories related to acidification and global warming potential. We took into account the energy consumptions (electricity and vessel fuel), the rearing infrastructure, including longlines, and a building for stabling, grading, and packing the mussel. Electricity contributes with 38.1 and 31.8 % respectively to global warming potential (GWP) and acidification, while fuel consumption contributes with 19.5 % to GWP and 31.8 % to acidification. Results of this work are compared with other LCA studies recently carried out in France (Aubin and Fontaine 2014) and in Spain (Iribarren et al. 2010c).Conclusions The LCA results show that important reductions in environmental impacts could be attained if the mussel farming activity would be operated according to the cooperative scenario here proposed. In this case, the environmental benefits will be a reduction of 3150 MJ and 156 kg CO2 eq per metric tonne of mussel produced, compared with the alternative scenario. The results of this study suggest that LCA should be applied to the seafood production sector in Algeria, in order to identify best management practices