![]() ‘Beyond adsorption’ descriptors in hydrogen electrocatalysis. In situ X-ray absorption spectroscopy of PtNi-nanowire/Vulcan XC-72R under oxygen reduction reaction in alkaline media. Amorphous Ni(OH) 2 nanoboxes: fast fabrication and enhanced sensing for glucose. ![]() Comparison of nanoscaled and bulk NiO structural and environmental characteristics by XRD, XAFS, and XPS. Hydrogen transfer through different crystal phases of nickel oxy/hydroxide. Structure–property relationships describing the buried interface between silicon oxide overlayers and electrocatalytic platinum thin films. The role of alkali metal cations and platinum-surface hydroxyl in the alkaline hydrogen evolution reaction. Development of MOF-derived carbon-based nanomaterials for efficient catalysis. Atomically dispersed iron hydroxide anchored on Pt for preferential oxidation of CO in H 2. US Department of Energy Hydrogen and Fuel Cells Program: 2019 Annual Merit Review and Peer Evaluation Report (National Renewable Energy Laboratory, 2020)Ĭao, L. Recent progress in alkaline water electrolysis for hydrogen production and applications. Hydrogen evolution and oxidation: mechanistic studies and material advances. Aqueous synthesis of ultrathin platinum/non-noble metal alloy nanowires for enhanced hydrogen evolution activity. Trends in activity for the water electrolyser reactions on 3 dM(Ni,Co,Fe,Mn)hydr(oxy)oxide catalysts. Surface-engineered PtNi-O nanostructure with record-high performance for electrocatalytic hydrogen evolution reaction. Ultrathin platinum nanowires grown on single-layered nickel hydroxide with high hydrogen evolution activity. The markedly improved hydrogen evolution reaction activity and durability in an alkaline medium promise an attractive catalyst material for alkaline water electrolysers and renewable chemical fuel generation. The proton conductive Ni(OH) 2 shell can also effectively reject impurity ions and retard the Oswald ripening, endowing a high tolerance to solution impurities and exceptional long-term durability that is difficult to achieve in the naked Pt catalysts. This design creates a favourable local chemical environment to result in acidic-like hydrogen evolution reaction kinetics with a lowest Tafel slope of 27 mV per decade and a record-high specific activity and mass activity in alkaline electrolyte. Here we report a unique design of ‘Ni(OH) 2-clothed Pt-tetrapods’ with an amorphous Ni(OH) 2 shell as a water dissociation catalyst and a proton conductive encapsulation layer to isolate the Pt core from bulk alkaline electrolyte while ensuring efficient proton supply to the active Pt sites. To confirm your answer, compare the calculated value to the weighted mass displayed on the periodic table.In analogy to natural enzymes, an elaborated design of catalytic systems with a specifically tailored local chemical environment could substantially improve reaction kinetics, effectively combat catalyst poisoning effect and boost catalyst lifetime under unfavourable reaction conditions. The atomic mass of oxygen (use percent natural abundance data from Table 2.5.1) would be calculated as follows:Ītomic mass = (%1)(mass 1) (%2)(mass 2) (%3)(mass 3) ![]() For chlorine, there are only two naturally occurring isotopes so there are only two terms.Ītomic mass = (%1)(mass 1) (%2)(mass 2) ⋯Īnother example: oxygen exists as a mixture that is 99.759% 16O, 0.037% 17O and 0.204% 18O. This is repeated until there is a term for each isotope. ![]() The weighted average is determined by multiplying the percent of natural abundance by the actual mass of the isotope. The atomic mass of an element is the weighted average of the atomic masses of the naturally occurring isotopes of that element. Why? The reason is that we need to take into account the natural abundance percentages of each isotope in order to calculate what is called the weighted average. = 35.968 \,u \nonumber \]Īs you can see, the average atomic mass given in the last column of the table above (35.453) is significantly lower. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |