Suchergebnisse

Abstract
Carbon, the human's most reliable fuel type in the past, must be neutralized in this century toward the Paris Agreement temperature goals. Solar power is widely believed a key fossil fuel substitute but suffers from the needs of large space occupation and huge energy storage for peak shaving. Here, we propose a solar network circumnavigating the globe to connecting large-scale desert photovoltaics among continents. By evaluating the generation potential of desert photovoltaic plants on each continent (taking dust accumulation into account) and the hourly maximum transmission potential that each inhabited continent can receive (taking transmission loss into account), we find that the current total annual human demand for electricity will be more than met by this solar network. The local imbalanced diurnal generation of photovoltaic energy can be made up by transcontinental power transmission from other power stations in the network to meet the hourly electricity demand. We also find that laying solar panels over a large space may darken the Earth's surface, but this albedo warming effect is orders of magnitude lower than that of CO2 released from thermal power plants. From practical needs and ecological effects, this powerful and stable power network with lower climate perturbability could potentially help to phase out global carbon emissions in the 21st century.

A cost-effective and scalable approach was developed to produce monodisperse Ni2−xCoxP nanocrystals (NCs) with composition tuned over the entire range (0 ≤ x ≤ 2). Ni2−xCoxP NCs were synthesized using low-cost, stable and low-toxicity triphenyl phosphite (TPP) as a phosphorus source, metal chlorides as metal precursors and hexadecylamine (HDA) as a ligand. The synthesis involved the nucleation of amorphous Ni–P and its posterior crystallization and simultaneous incorporation of Co. The composition, size and morphology of the Ni2−xCoxP NCs could be controlled simply by varying the ratio of Ni and Co precursors and the amounts of TPP and HDA. Ternary Ni2−xCoxP-based electrocatalysts exhibited enhanced electrocatalytic activity toward the hydrogen evolution reaction (HER) compared to binary phosphides. In particular, NiCoP electrocatalysts displayed the lowest overpotential of 97 mV at J = 10 mA cm−2 and an excellent long-term stability. DFT calculations of the Gibbs free energy for hydrogen adsorption at the surface of Ni2−xCoxP NCs showed NiCoP to have the most appropriate composition to optimize this parameter within the whole Ni2−xCoxP series. However, the hydrogen adsorption energy was demonstrated not to be the only parameter controlling the HER activity in Ni2−xCoxP. ; J. David and J. Arbiol acknowledge funding from Generalitat de Catalunya 2017 SGR 327 and the Spanish MINECO project VALPEC (ENE2017-85087-C3). ICN2 acknowledges support from the Severo Ochoa Programme (SEV-2013-0295) and is funded by the CERCA Programme/Generalitat de Catalunya. J. David has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 665919. J. Llorca is a Serra Hunter Fellow and is grateful to the ICREA Academia program and grants MINECO/FEDER ENE2015-63969-R and GC 2017 SGR 128. J. Liu, J. Li and X. Yu thank the China Scholarship Council for scholarship support. M. Meyns acknowledges a Juan de la Cierva formación grant by the Spanish MINECO. ; Peer reviewed

The applicability of a multi-step generic procedure to systematically develop sample preparation methods for the detection, characterization, and quantification of inorganic engineered nanoparticles (ENPs) in a complex matrix was successfully demonstrated. The research focused on the optimization of the sample preparation, aiming to achieve a complete separation of ENPs from a complex matrix without altering the ENP size distribution and with minimal loss of ENPs. The separated ENPs were detected and further characterized in terms of particle size distribution and quantified in terms of elemental mass content by asymmetric flow-field flow fractionation coupled to a multi-angle light scattering detector and an inductively coupled plasma mass spectrometer. Following the proposed generic procedure SiO2-ENPs were separated from a tomato soup. Two potential sample preparation methods were tested these being acid digestion and colloidal extraction. With the developed method a complete SiO2-ENPs and matrix separation with a Si mass recovery >90% was achieved by acid digestion. The alteration of the particle size distribution was minimized by particle stabilization. The generic procedure which also provides quality criteria for method development is urgently needed for standardized and systematic development of procedures for separation of ENPs from a complex matrix. The chosen analytical technique was shown to be suitable for detecting SiO2-ENPs in a complex food matrix like tomato soup and may therefore be extended to monitor the existence of ENPs during production and safety control of foodstuffs, food labelling, and compliance with legislative limits.