Electrocatalytic water oxidation is a rate-determining step in the water splitting reaction. Here, we report one single atom W 6+ doped Ni(OH) 2 nanosheet sample (w-Ni(OH) 2 ) with an outstanding oxygen evolution reaction (OER) performance that is, in a 1 M KOH medium, an overpotential of 237 mV is obtained reaching a current density of 10 mA/cm 2 . Moreover, at high current density of 80 mA/cm 2 , the overpotential value is 267 mV. The corresponding Tafel slope is measured to be 33 mV/dec. The d 0 W 6+ atom with a low spin-state has more outermost vacant orbitals, resulting in more water and OH − groups being adsorbed on the exposed W sites of the Ni(OH) 2 nanosheet. Density functional theory (DFT) calculations confirm that the O radical and O-O coupling are both generated at the same site of W 6+ . This work demonstrates that W 6+ doping can promote the electrocatalytic water oxidation activity of Ni(OH) 2 with the highest performance.

Developing cost-effective, high-performance nitrogen reduction reaction (NRR) electrocatalysts is required for the production of green and low-cost ammonia under ambient conditions. Here, a strategy is proposed to adjust the reaction preference of noble metals by tuning the size and local chemical environment of the active sites. This proof-of-concept model is realized by single ruthenium atoms distributed in a matrix of graphitic carbon nitride (Ru SAs/g-C 3 N 4 ). This model is compared, in terms of the NRR activity, to bulk Ru. The as-synthesized Ru SAs/g-C 3 N 4 exhibits excellent catalytic activity and selectivity with an NH 3 yield rate of 23.0 µg mg cat −1 h −1 and a Faradaic efficiency as high as 8.3% at a low overpotential (0.05 V vs the reversible hydrogen electrode), which is far better than that of the bulk Ru counterpart. Moreover, the Ru SAs/g-C 3 N 4 displays a high stability during five recycling tests and a 12 h potentiostatic test. Density functional theory calculations reveal that compared to bulk Ru surfaces, Ru SAs/g-C 3 N 4 has more facile reaction thermodynamics, and the enhanced NRR performance of Ru SAs/g-C 3 N 4 originates from a tuning of the d-electron energies from that of the bulk to a single-atom, causing an up-shift of the d-band center toward the Fermi level.can maximize metal utilization. Since SACs have unique catalytic sites, they usually exhibit a distinct catalytic selectivity as compared to their nanoclusters or nanoparticle counterparts. [2] For example, single atomic Pt immobilized in the surface of Ni nanocrystals shows a higher activity and chemoselectivity toward the hydrogenation of 3-nitrostyrene. [3] Isolated Co single-site catalysts anchored on a N-doped porous carbon nanobelt exhibits an excellent catalytic performance for oxidation of ethylbenzene with 98% conversion and 99% selectivity, whereas the Co nanoparticles are essentially inert. [4] Moreover, atomic Ni-anchored covalent triazine framework has a remarkable selectivity for the conversion of CO 2 to CO, with a Faradaic efficiency (FE) of > 90% over the range of −0.6 to −0.9 V versus the reversible hydrogen electrode (RHE). [5] In view of these reported works, it is evident that the size of metal particles is a key factor in determining their catalytic performance, and decreasing the size offers an intriguing opportunity to alter the activity and selectivity of these metal catalysts. SACs, as the limit of size reduction, hold great potential to achieve high activity and selectivity in catalytic reactions.Recently, the electrocatalytic N 2 reduction reaction (NRR) in aqueous electrolytes for synthesizing ammonia at ambient

As an emerging battery technology, metal-air flow batteries inherit the advantageous features of the unique structural design of conventional redox flow batteries and the high energy density of metal-air batteries, thus showing great potential as efficient electrochemical systems for large-scale electrical energy storage. This review summarizes the operating principles and recent progress of metal-air flow batteries from a materials and chemistry perspective, with particular emphasis on the latest advanced materials design and cell configuration engineering, which the authors divide into three categories based on the anode

A strategy for finding new electrocatalysts for the oxygen reduction reaction (ORR) in acidic solutions is outlined and illustrated with results for Pd-Co catalysts. This is based on establishing guidelines for selecting test systems, rapid preparation of arrays, and rapid screening by scanning electrochemical microscopy. Promising candidates are further tested as supported electrocatalysts by larger scale electrochemical methods and in fuel cells, with optimization of the composition and structure. Those that emerge are characterized by a variety of methods, including X-ray diffraction, scanning electron microscopy, and X-ray photoemission spectroscopy. Finally, density functional theory is used for detailed calculations of oxygen adsorption and dissociation on the material and provides better guidelines for further testing.

High resolution infrared emission spectra of aluminum monohydride and monodeuteride have been recorded. Gaseous AlH and AID were generated by reacting molten aluminum metal with hydrogen and deuterium gas. Approximately 265 AIH lines with V= 1-+0 to v=5-+4 and 470 AID lines with v = 1 -+ 0 to v = 7 -+ 6 are reported. Dunham Y ij constants were obtained by fitting the data of each isotopomer separately to the Dunham energy level expression while massreduced Dunham U ij constants were obtained from a combined fit of all isotopomer data. A second set of Dunham U ij constants was obtained from a fit where U;/s with j < 2 were treated as adjustable parameters and all remaining Ui/s fixed to values that satisfy the constraints imposed by the Dunham model. Finally, an effective Born-Oppenheimer potential was determined by fitting all the data directly to the eigenvalues of the radial Schrodinger equation containing a parametrized potential function.

Absorption of thermal-energy gaseous hydrogen atoms by Si(100), exceeding by far the dopant and other impurity concentrations, occurs within a narrow substrate temperature (T(s)) window centered at approximately 460 K. The absorbed hydrogen persists in the crystalline bulk as highly mobile species before migrating out and desorbing as molecular hydrogen at T(s) as high as 900 K, well above the recombinative desorption temperatures of surface-adsorbed H. Developing and sustaining atomic-scale surface roughness, by H-induced silicon etching, is a prerequisite for H absorption and determines the T(s) window.

Glycerol electrolysis affords a green and energetically favorable route for the production of value‐added chemicals at the anode and H2 production in parallel at the cathode. Here, a facile method for trapping Pt nanoparticles at oxygen vacancies of molybdenum oxide (MoOx) nanosheets, yielding a high‐performance MoOx/Pt composite electrocatalyst for both the glycerol oxidation reaction (GOR) and the hydrogen evolution reaction (HER) in alkaline electrolytes, is reported. Combined electrochemical experiments and theoretical calculations reveal the important role of MoOx nanosheets for the adsorption of glycerol molecules in GOR and the dissociation of water molecules in HER, as well as the strong electronic interaction with Pt. The MoOx/Pt composite thus significantly enhances the specific mass activity of Pt and the kinetics for both reactions. With MoOx/Pt electrodes serving as both cathode and anode, two‐electrode glycerol electrolysis is achieved at a cell voltage of 0.70 V to reach a current density of 10 mA cm−2, which is 0.90 V less than that required for water electrolysis.

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