Search results for "NEWA"
showing 10 items of 2491 documents
Development of an Electrochemical Balance to Measure Quantitatively Hydrogen Generation during Electrochemical Processes
2017
A new method to measure the amount of hydrogen generated from the surface of an immersed electrode is presented in this work. The method consists of a mechanical balance with a horizontal arm attached to two hydrogen-collecting containers that are submerged in two independent electrochemical cells. One of the two cells (the test cell) contains the electrode of interest, generating an unknown amount of hydrogen, whereas the other cell (the measurement cell) contains an inert electrode that is used to evolve an amount of hydrogen equal to that generated in the test cell, such as the mechanical equilibrium between the sides of the balance is constantly maintained. Adequate electrical connectio…
Grand canonical rate theory for electrochemical and electrocatalytic systems I: General formulation and proton-coupled electron transfer reactions
2020
A generally valid rate theory at fixed potentials is developed to treat electrochemical and electrocatalytic potential-dependent electron, proton, and proton-coupled electron reactions. Both classical and quantum reactions in adiabatic and non-adiabatic limits are treated. The applicability and new information obtained from the theory is demonstrated for the gold catalyzed acidic Volmer reaction.
Immobilization of copper complexes with (1,10-phenanthrolinyl)phosphonates on titania supports for sustainable catalysis
2017
Different strategies for the immobilization of copper complexes with 1,10-phenanthroline (phen) using the phosphonate anchoring group were investigated to prepare robust and porous heterogeneous catalysts. Homoleptic and heteroleptic copper(I) complexes with phen bearing the bis(trimethylsiloxy)phosphoryl anchoring group (Pphen-Si) at different positions of the phen backbone were prepared and covalently incorporated into titania (TiO2) xerogels by using the sol–gel process or grafted onto the surface of mesoporous TiO2 (SBET = 650 m2 g−1). Copper(I) bis(Pphen-Si) complexes were the only complexes that were successfully anchored onto the TiO2 surface because the heterogenization was often ac…
Nanostructured electrodes for hydrogen production in alkaline electrolyzer
2018
Abstract Ever-widespread employment of renewable energy sources, such as wind and sun, request the simultaneous use of effective energy storage systems owing to the intermittent and unpredictable energy generation by these sources. The most reliable storage systems currently under investigation are batteries and electrochemical cells for hydrogen production from water splitting. Both systems store chemical energy which can be converted on demand. The low power density is the weakness of the batteries while the high production cost limits currently the wide use of hydrogen from electrochemical water splitting. In this work, attention was focused on the use of nanostructured Ni as a cathode f…
Metallic interconnects for solid oxide fuel cell: Effect of water vapour on oxidation resistance of differently coated alloys
2009
International audience; The need of interconnect to separate fuel and oxidant gasses and connect individual cells into electrical series in a SOFC stack appears as one of the most important point in fuel cell technology. Due to their high electrical and thermal conductivities, thermal expansion compatibility with the other cell components and lowcost, ferritic stainless steels (FSS) are nowconsidered to be among the most promising candidate materials as interconnects in SOFC stacks. Despite the formation at 800 ◦C of a protective chromia Cr2O3 scale, it can transform in volatile chromium species, leading to the lost of its protectiveness and then the degradation of the fuel cell. A previous…
A Mechanical–Electrochemical Approach for the Determination of Precursor Sites for Pitting Corrosion at the Microscale
2006
International audience; The influence of metallurgical defects and residual surface stresses generated by polishing on the pitting susceptibility of duplex stainless steels was studied by combining macro- and microelectrochemical measurements with thermal-mechanical simulation and metallography tests. It has been shown that pits initiate in both phases at metallurgical point defects (such as oxide inclusions in the ferrite and dislocation lines in the austenite). By contrast, the surface stress state was the driving force for pit initiation along the austenite/ferrite interface. Experiments at the macroscale revealed that this process represents about 40% of the total number of pits observe…
Dismantling and electrochemical copper recovery from Waste Printed Circuit Boards in H2SO4–CuSO4–NaCl solutions
2019
Abstract The worldwide growing of electrical and electronic equipment makes increasingly urgent to find environmentally friendly treatments for e-waste. In this paper, the attention has been focused on i) the eco-friendly dismantling of the electronic components from Waste Printed Circuit Boards and ii) recovering of pure metallic copper, which is the most abundant metal and one of the most valuable in Printed Circuit Boards. After an experimental optimization study, we found that a solution containing 0.5 M H2SO4, 0.4 M CuSO4, and 4 M NaCl can be successfully used to disassemble the electronic components from the boards by leaching of all exposed metals. Air was blown into the leaching sol…
Dithienopyrrolobenzothiadiazole-based organic dyes for efficient dye-sensitized solar cells
2014
Four novel D–π–A metal-free organic dyes DTP1–4 containing a dithienopyrrolobenzothiadiazole (DTPBT) unit were synthesized and applied in dye-sensitized solar cells, where DTPBT was employed as a π-spacer for the first time. The photophysical, electrochemical and photovoltaic properties of the dyes were systematically investigated. The dyes DTP1–4 showed broad absorption spectra and high molar extinction coefficient, resulting in high light harvesting efficiency. In addition, the impacts of donors and the thiophene unit as an additional π-spacer were also studied. The results showed that the dye DTP4 with triphenylamine as the donor exhibited better photovoltaic performance than DTP1–3 with…
Effect of Ni content on the structure and hydrogenation property of mechanically alloyed TiMgNix ternary alloys
2017
Abstract In this study, TiMgNix samples (x = 0.2, 0.4, 0.6, 0.8, 1) have been prepared by mechanical alloying using a planetary high-energy ball mill. The structural transformations were characterized by XRD and indicated that all the as-milled TiMgNix alloys consist of mixtures of crystalline Mg and amorphous Ti-Ni-(Mg) phase. TEM analyses also show that nanocrystallites and amorphous phases coexist in the as-milled TiMgNi alloy. Electrochemical test shows that the TiMgNi composition yields the highest discharge capacity. The discharge capacities and activation properties of TiMgNix alloys linearly increase with increasing Ni content. The MgTiNi0.8 composition boasts the best cycling prope…
Coated interconnects development for high temperature water vapour electrolysis: Study in anode atmospher
2013
International audience; High temperature water vapour electrolysis (HTE) is an efficient technology for hydrogen production. In this context, a commercial stainless steel, K41X (AISI 441), was chosen as interconnect. In a previous paper, the high temperature corrosion and the electrical conductivity were evaluated in both anode (O-2-H2O) and cathode (H-2-H2O) atmosphere at 800 degrees C. In O-2-H2O atmosphere, the formation of a thin chromia protective layer was observed. Nevertheless, the ASR parameter measured was higher than the maximum accepted value. These results, in addition with chromium evaporation measurements, proved that the K41X alloy is not suitable for HTE interconnect applic…