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Metallic hydrogen

Zhengyan Zhao, Xuedan Song, Lei Liu, Guanglan Li, Shaheen Shah, Ce Hao
This article presents a recognition mechanism for nitro-explosives by the luminescent metal-organic framework 1 (LMOF-1) with the aid of density functional theory (DFT) and time-dependent density functional theory (TDDFT). The behavior of hydrogen bonding between the LMOF-1 and nitro-explosives in the S1 state is closely associated with the fluorescence properties of the LMOF-1. In our research, we calculated the geometric configuration, 1H NMR and IR spectra of the Complex 2 formed by LMOF-1 and nitrobenzene in the S0 and S1 states...
January 5, 2018: Journal of Molecular Graphics & Modelling
Yu-Jie Wang, Yang-Yang Zhou, Hong-Guo Hao, Man Song, Na Zhang, Shuang Yao, Jing-Hui Yan, Zhi-Ming Zhang, Tong-Bu Lu
Two robust metal-organic frameworks (MOFs), {H4[Ni(π-H2O)2]2[Ni(rt-H2O)2]8Ni4(Tri)24}[VIVW12O40]2·24H2O (1) and {H[Ni(π-O)2]2[Ni(rt-H2O)2]8Ni4(Tri)24}[VIVW10VV2O40V2][VIVW9VV3O40VIV2]·24H2O (2) (Tri = 1,2,4-triazole), composed of polyoxometalates (POMs) and metal-organic units, were designed and synthesized by a hydrothermal method. Structure analysis indicates that there is a metal-organic crown [{Ni3(Tri)6(H2O)4}4] ({Ni12}) in these two compounds. In 1, the {Ni12} crown embraces four pendant Tri ligands that could capture a cationic [Ni(H2O)2]2+ group, resulting in the Ni13-Tri building unit [Ni(H2O)2{Ni3(Tri)6(H2O)4}4] ({Ni13})...
January 18, 2018: Inorganic Chemistry
Fei Pang, Ruifang Zhang, Dengpeng Lan, Jianping Ge
Hybrid nanoparticles have intrinsic advantages to achieve better activity in photocatalysis compared to single component materials, as it can synergistically combine functional components which promote light absorption, charge transportation, surface reaction and catalyst regeneration. Through functional modular assembly, a rational and stepwise approach has been developed to construct Fe3O4-CdS-Au trimer nanoparticles and its derivatives as magnetically separable catalysts for photothermo-catalytic hydrogen evolution from water...
January 18, 2018: ACS Applied Materials & Interfaces
Wei Fang, Jeremy O Richardson, Ji Chen, Xin-Zheng Li, Angelos Michaelides
Hydrogen diffusion on metals exhibits rich quantum behavior, which is not yet fully understood. Using simulations, we show that many hydrogen diffusion barriers can be categorized into those with parabolic tops and those with broad tops. With parabolic-top barriers, hydrogen diffusion evolves gradually from classical hopping, to shallow tunneling, to deep tunneling as the temperature (T) decreases, and noticeable quantum effects persist at moderate T. In contrast, with broad-top barriers quantum effects become important only at low T and the classical-to-quantum transition is sharp, at which classical hopping and deep tunneling both occur...
September 22, 2017: Physical Review Letters
Saumyak Mukherjee, Sayantan Mondal, Ashish Anilrao Deshmukh, Balasubramanian Gopal, Biman Bagchi
Self-assembly of proteins often gives rise to interesting quasi-stable structures that serve important biological purposes. Insulin hexamer is such an assembly. While monomer is the biologically active form of insulin, hexamer serves as the storehouse of the hormone. The hexamer also prevents the formation of higher order aggregates. While several studies explored the role of bivalent metal ions like Zn2+, Ca2+ etc. in the stabilization of the hexameric form, the role of water molecules has been ignored. We combine molecular dynamics simulations, quantum calculations and X-ray analyses to discover that a team of approximately ten water molecules confined inside a barrel-shaped nano-cavity at the center of insulin hexamer is one of the major causes that account for the unusual stability of the biomolecular assembly...
January 17, 2018: Journal of Physical Chemistry. B
Yuan Pan, Kaian Sun, Shoujie Liu, Xing Cao, Konglin Wu, Weng-Chon Cheong, Zheng Chen, Yu Wang, Yang Li, Yunqi Liu, Dingsheng Wang, Qing Peng, Chen Chen, Yadong Li
The construction of highly active and stable non-noble metal electrocatalysts for hydrogen and oxygen evolution reactions electrocatalysts is a major challenge for overall water splitting. Herein, we report a novel hybrid nanostructure with CoP na-noparticles (NPs) embedded in N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis-oxidation-phosphidation strategy derived from core-shell ZIF-8@ZIF-67. Benefiting from the synergistic effects between highly active CoP NPs and NCNHP, the CoP/NCNHP hybrid exhibited outstanding bifunctional electrocatalytic performances...
January 17, 2018: Journal of the American Chemical Society
Zhong-Hua Xue, Jing-Tan Han, Wei-Jie Feng, Qiu-Ying Yu, Xin-Hao Li, Markus Antonietti, Jie-Sheng Chen
Engineering the adsorption of molecules on active sites is an integral and challenging part for the design of highly efficient transition-metal-based catalysts for methanol dehydrogenation. Here we report a Mott-Schottky catalyst composed of Ni nanoparticles and tailorable nitrogen-doped carbon-foam (Ni/NCF) and thus tunable adsorption energy for highly efficient and selective dehydrogenation of gas-phase methanol to hydrogen and CO even under relatively high weight hourly space velocities (WHSV). Both theoretical and experimental results reveal the key role of the rectifying contact at the Ni/NCF boundaries in tailoring the electron density of Ni species and enhancing the absorption energies of methanol molecules, which leads to a remarkably high turnover frequency (TOF) value (356 mol methanol mol-1 Ni h-1 at 350 °C), 10-fold outpacing the bench-marked transition-metal catalysts in the literature...
January 17, 2018: Angewandte Chemie
Yonghui Tian, Shuangli Hu, Xiao-Lan Sheng, Yixiang Duan, Jacek Jakowski, Bobby G Sumpter, Jingsong Huang
The prevalent catalysts for natural and artificial N2 fixation are known to hinge upon transition metal (TM) elements. Herein, we demonstrate by density functional theory that Al-doped graphene is a potential non-TM catalyst to convert N2 to NH3 in the presence of relatively mild proton/electron sources. In the integrated structure of catalyst, the Al atom serves as a binding site and catalytic center while the graphene framework severs as an electron buffer during the successive proton/electron additions to N2 and its various downstream NxHy intermediates...
January 16, 2018: Journal of Physical Chemistry Letters
Mansi S Shah, Michael Tsapatsis, J Ilja Siepmann
No abstract text is available yet for this article.
January 17, 2018: Chemical Reviews
Zhixue Bai, Wenhao Dong, Yipeng Ren, Cong Zhang, Qiang Chen
The flourish of nanotechnology has brought new vitality to the research and development of electrochemical sensing materials. In this work, we successfully synthesized Nano Au & Pt alloy microspheres decorated with reduced graphene oxide (RGO/nAPAMSs) by a simple, facile and eco-friendly one-step reduction strategy for the fabrication of highly sensitive non-enzymatic H2O2 sensing interfaces. Energy-dispersive X-ray spectroscopy mapping (EDX mapping), energy-dispersive X-ray spectroscopy analyzer (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR) and X-ray diffraction spectrum (XRD) were employed to characterize RGO/nAPAMSs from a microscopic perspective...
January 16, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Isaac N Mills, Jonathan A Porras, Stefan Bernhard
The exponential growth in published studies on phosphorescent metal complexes has been triggered by their utilization in optoelectronics, solar energy conversion, and biological labeling applications. Very recent breakthroughs in organic photoredox transformations have further increased the research efforts dedicated to discerning the inner workings and structure-property relationships of these chromophores. Initially, the principal focus was on the Ru(II)-tris-diimine complex family. However, the limited photostability and lack of luminescence tunability discovered in these complexes prompted a broadening of the research to include 5d transition metal ions...
January 16, 2018: Accounts of Chemical Research
Narendra Kumar Alam Venugopal, Shuli Yin, Yinghao Li, Hairong Xue, You Xu, Xiaonian Li, Hongjing Wang, Liang Wang
Tailoring of new hydrogen evolution reaction (HER) electrocatalyst with earth abundant elements is important for large scale water splitting and hydrogen production. In this work, we present a simple synthetic method for incorporating iron phosphide (FeP) particles into three-dimensional (3D) porous graphene aerogel (GA) structure. The FeP formed in porous 3D GA (FeP/GA) is derived from electroactive Fe hexacyanoferrate (FeHCF). The advantage of incorporating FeP, in the porous 3D graphene network enables high accessibility for HER...
January 16, 2018: Chemistry, An Asian Journal
Anton V Savchenkov, Anna V Vologzhanina, Artem O Dmitrienko, Yan V Zubavichus, Denis V Pushkin, Larisa B Serezhkina, Viktor N Serezhkin
Single crystals of Na[(UO2)(i-C3H7COO)3]·0.7H2O (I), Cs[(UO2)(i-C3H7COO)3] (II) and (NH4)[(UO2)(i-C4H9COO)3] (III) were obtained via isothermal evaporation and their structures were solved using X-ray diffraction techniques. Even though the ligands are branched, bulky and spatial, many carbon and hydrogen atoms are still disordered in these crystal structures at low temperature. A new type of Na coordination is observed for the first time for this family of compounds, proposing high sensitivity of compound I to humidity...
January 16, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Alexander M Khenkin, Madhu Vedichi, Linda J W Shimon, Matthew A Cranswick, Johannes E M N Klein, Lawrence Que, Ronny Neumann
The iron(II) triflate complex (1) of 1,2-bis(2,2'-bipyridyl-6-yl)ethane, with two bipyridine moieties connected by an ethane bridge, was prepared. Addition of aqueous 30% H2O2 to an acetonitrile solution of 1 yielded 2, a green compound with λmax=710 nm. Moessbauer measurements on 2 showed a doublet with an isomer shift (δ) of 0.35 mm/s and a quadrupole splitting (ΔEQ) of 0.86 mm/s, indicative of an antiferromagnetically coupled diferric complex. Resonance Raman spectra showed peaks at 883, 556 and 451 cm-1 that downshifted to 832, 540 and 441 cm-1 when 1 was treated with H218O2...
November 2017: Israel Journal of Chemistry
H Ashassi-Sorkhabi, S Abolghasemi-Fakhri, B Rezaei Moghadam, H Javan
An efficient and non-precious metal catalyst is a key factor for hydrogen evolution reaction (HER). Here we report that the fabrication of highly ordered porous arrays of Cu-Zn-Ni alloy has been carried out in a one-step electrochemical route at a constant apparent current density of -3 A·cm-2. The optimum film composition and reactivity of the electrodes for catalytic hydrogen evolution reaction were analyzed by using different current densities, deposition time and bath concentration. For this purpose, onset potentials in linear sweep voltammograms (LSV) were compared...
January 8, 2018: Journal of Colloid and Interface Science
Erik Andris, Prokopis Andrikopoulos, Jiří Schulz, Jan Turek, Aleš Růžička, Jana Roithová, Lubomír Rulíšek
Attractive metallophilic (aurophilic, argentophilic, cuprophilic, …) interactions play an important role in arrangement and stabilization of oligonuclear metal ion complexes. We report a combined experimental and theoretical assessment of aurophilic interactions in closed-shell gold(I) dimers. The experimental binding energies were obtained for charged [(LH)AuCl]+…[(L')AuCl] dimers (L is either a phosphine or a N-heterocyclic carbene ligand) in the gas phase. These energies served for benchmarking of correlated quantum chemical calculations (CCSD(T)-calibrated SCS-MP2/CBS method) that were then applied to neutral [(L)AuX]…[(L')AuX] dimers (X = Cl, Br, I)...
January 15, 2018: Journal of the American Chemical Society
Georgy A Filonenko, Robbert van Putten, Emiel J M Hensen, Evgeny A Pidko
Catalytic hydrogenation and dehydrogenation reactions form the core of the modern chemical industry. This vast class of reactions is found in any part of chemical synthesis starting from the milligram-scale exploratory organic chemistry to the multi-ton base chemicals production. Noble metal catalysis has long been the key driving force in enabling these transformations with carbonyl substrates and their nitrogen-containing counterparts. This review is aimed at introducing the reader to the remarkable progress made in the last three years in the development of base metal catalysts for hydrogenations and dehydrogenative transformations...
January 15, 2018: Chemical Society Reviews
Hui Li, Qi Li, Peng Wen, Trey B Williams, Shiba Adhikari, Chaochao Dun, Chang Lu, Dominique Itanze, Lin Jiang, David L Carroll, George L Donati, Pamela M Lundin, Yejun Qiu, Scott M Geyer
Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this work, highly monodisperse CoP and Co2 P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co2 P NCs show higher OER performance owing to easier formation of plentiful Co2 P@COOH heterojunctions...
January 15, 2018: Advanced Materials
Ying Yang, Wen Zhang, Feng Yang, Biao Zhou, Dehong Zeng, Na Zhang, Guoming Zhao, Shijie Hao, Xin Zhang
A green and sustainable approach for biorefining involves the development of bifunctional catalysts for the one-pot conversion of cellulosic biomass to isosorbide. This requires highly efficient, easily separated and versatile metal-acid catalysts for hydrolysis-hydrogenation-dehydration cascade reactions. Herein, we report a new type of metal-acid bifunctional catalyst by dispersing Ru nanoparticles (NPs) on magnetic yolk-shell nanoarchitectures comprising an Fe3O4 core and a sulfoacid (SO3H)-containing periodic mesoporous organosilica shell...
January 15, 2018: Nanoscale
Lvlv Ji, Cuncai Lv, Zuofeng Chen, Zhipeng Huang, Chi Zhang
Hydrogen is considered a promising energy carrier for replacing traditional fossil fuels. Electrochemical or solar-driven water splitting is a green and sustainable method of producing hydrogen. To lower the overpotential and minimize energy costs, numerous reports have focused on developing noble-metal-free catalysts for hydrogen production, with special attention paid to nickel-based materials. Herein, the current state of research on the use of Ni-based materials as electrocatalysts, cocatalysts, and photoactive materials in hydrogen production is reviewed...
January 15, 2018: Advanced Materials
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