Chemical and Electrochemical O2 Reduction on Earth-Abundant M-N-C Catalysts and Implications for Mediated Electrolysis

Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.

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Room Temperature Alkali Metal Reduction of Carbon Dioxide

10.26434/chemrxiv.12665336 ◽

2020 ◽

Author(s):

Lucas A. Freeman ◽

Akachukwu D. Obi ◽

Haleigh R. Machost ◽

Andrew Molino ◽

Asa W. Nichols ◽

...

Keyword(s):

Alkali Metal ◽

Alkali Metals ◽

Room Temperature ◽

Chemical Reduction ◽

Bond Cleavage ◽

Open Shell ◽

Metal Reduction ◽

One Pot ◽

Earth Abundant ◽

Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO2 to access useful CO2-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO2 and the MGE. Herein we report the first successful chemical reduction of CO2 at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO2 adduct (1) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO2)]n(M = Li, Na, K, 2-4) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M2(CAAC–CO2)]n (5-8). It is notable that these crystalline clusters of reduced CO2 may also be isolated via the “one-pot” reaction of free CO2 with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products 2-8 were investigated using a combination of experimental and theoretical methods.

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Oxygen-Oxygen Bond Cleavage and Formation in Co(II) Mediated Stoichiometric O2 Reduction via the Potential Intermediacy of a Co(IV) Oxyl Radical

10.26434/chemrxiv.7176392 ◽

2018 ◽

Author(s):

Lucie Nurdin ◽

Denis M. Spasyuk ◽

Laura Fairburn ◽

Warren Piers ◽

Laurent Maron

Keyword(s):

Bond Cleavage ◽

Peroxo Complex ◽

Oxygen Oxygen ◽

O2 Reduction ◽

Oxygen Bond ◽

Pentadentate Ligand

Diprotonation of a remarkably stable, toluene soluble cobalt peroxo complex supported by a neutral, dianionic pentadentate ligand leads to facile O-O bond cleavage and production of a highly reactive Co(IV) oxyl cation intermediate that dimerizes and releases O2. These processes are relevant to both O2 reduction and O2 evolution and the mechanism was probed in detail both experimentally and computationally.

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Workfunction of Al-Doped ZnO Films Deposited by Atomic Layer Deposition

10.26434/chemrxiv.5850003 ◽

2018 ◽

Author(s):

Peter George Gordon ◽

Goran Bacic ◽

Gregory P. Lopinski ◽

Sean Thomas Barry

Keyword(s):

Atomic Layer Deposition ◽

Atomic Layer ◽

Atomic Ratio ◽

Aluminum Concentration ◽

Zno Films ◽

Transparent Conductor ◽

Kelvin Probe ◽

Layer Deposition ◽

Earth Abundant ◽

Doped Zno

Al-doped ZnO (AZO) is a promising earth-abundant alternative to Sn-doped In2O3 (ITO) as an n-type transparent conductor for electronic and photovoltaic devices; AZO is also more straightforward to deposit by atomic layer deposition (ALD). The workfunction of this material is particularly important for the design of optoelectronic devices. We have deposited AZO films with resistivities as low as 1.1 x 10-3 Ωcm by ALD using the industry-standard precursors trimethylaluminum (TMA), diethylzinc (DEZ), and water at 200◦C. These films were transparent and their elemental compositions showed reasonable agreement with the pulse program ratios. The workfunction of these films was measured using a scanning Kelvin Probe (sKP) to investigate the role of aluminum concentration. In addition, the workfunction of AZO films prepared by two different ALD recipes were compared: a “surface” recipe wherein the TMA was pulsed at the top of each repeating AZO stack, and a interlamellar recipe where the TMA pulse was introduced halfway through the stack. As aluminum doping increases, the surface recipe produces films with a consistently higher workfunction as compared to the interlamellar recipe. The resistivity of the surface recipe films show a minimum at a 1:16 Al:Zn atomic ratio and using an interlamellar recipe, minimum resistivity was seen at 1:19. The film thicknesses were characterized by ellipsometry, chemical composition by EDX, and resistivity by four-point probe.

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Dimers, monomers and pentacoordination in a series of earth-abundant transition metal dibromido complexes supported by a neutral SNS ligand framework

Polyhedron ◽

10.1016/j.poly.2018.07.033 ◽

2018 ◽

Vol 154 ◽

pp. 252-258

Author(s):

Yasmeen Hameed ◽

Sarah Ouanounou ◽

Titel Jurca ◽

Bulat Gabidullin ◽

Ilia Korobkov ◽

...

Keyword(s):

Transition Metal ◽

Earth Abundant ◽

Sns Ligand

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Deposition and characterization of earth abundant CuZnS ternary thin films by vacuum spray pyrolysis and fabrication of p‐ CZS/ n‐AZO heterojunction solar cells

International Journal of Energy Research ◽

10.1002/er.5515 ◽

2020 ◽

Vol 44 (9) ◽

pp. 7778-7788

Author(s):

Aabel P ◽

Santhosh Kumar M C

Keyword(s):

Thin Films ◽

Solar Cells ◽

Spray Pyrolysis ◽

Heterojunction Solar Cells ◽

Earth Abundant

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The Prepartion of Co@C3N4 Catalyst and Applications on Synthesis of Quinolines from 2-Aminobenzyl Alcohols with Ketones

New Journal of Chemistry ◽

10.1039/d0nj05767c ◽

2021 ◽

Author(s):

Fei Cao ◽

Anruo Mao ◽

Bobin Yang ◽

Chenyang Ge ◽

Dawei Wang

Keyword(s):

Energy Consumption ◽

Metal Complex ◽

Environmental Friendliness ◽

Triazole Ligand ◽

Earth Abundant

The unsymmetrical diphenylphosphino-pyridinyl-triazole ligand was synthesized and characterized through IR, NMR and MS and the corresponding earth-abundant metal complex (cobalt) was prepared. Considering energy consumption and environmental friendliness, it is...

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Engineering Sulfur Vacancies into Fe9S10 Nanosheet Arrays for Efficient Alkaline Hydrogen Evolution

Nanoscale ◽

10.1039/d1nr02762j ◽

2021 ◽

Author(s):

Wenjun He ◽

Jianing Cheng ◽

Yaohui Gao ◽

Caichi Liu ◽

Jianling Zhao ◽

...

Keyword(s):

Transition Metal ◽

Hydrogen Evolution ◽

Hydrogen Evolution Reaction ◽

Metal Sulfides ◽

Transition Metal Sulfides ◽

Nanosheet Arrays ◽

Excellent Activity ◽

Earth Abundant ◽

Iron Based

The development of earth-abundant transition metal sulfides electrocatalysts with excellent activity and stability toward alkaline hydrogen evolution reaction (HER) is critical but challenging. Iron-based sulfides are favored due to their...

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Defect and Doping Co-Engineered Non-Metal Nanocarbon ORR Electrocatalyst

Nano-Micro Letters ◽

10.1007/s40820-020-00579-y ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Jian Zhang ◽

Jingjing Zhang ◽

Feng He ◽

Yijun Chen ◽

Jiawei Zhu ◽

...

Keyword(s):

Rational Design ◽

Low Cost ◽

Reduction Reaction ◽

Defect Engineering ◽

Heteroatom Doping ◽

Competitive Activity ◽

Design And Manufacturing ◽

Earth Abundant ◽

Induced Defects ◽

Carbon Based

AbstractExploring low-cost and earth-abundant oxygen reduction reaction (ORR) electrocatalyst is essential for fuel cells and metal–air batteries. Among them, non-metal nanocarbon with multiple advantages of low cost, abundance, high conductivity, good durability, and competitive activity has attracted intense interest in recent years. The enhanced ORR activities of the nanocarbons are normally thought to originate from heteroatom (e.g., N, B, P, or S) doping or various induced defects. However, in practice, carbon-based materials usually contain both dopants and defects. In this regard, in terms of the co-engineering of heteroatom doping and defect inducing, we present an overview of recent advances in developing non-metal carbon-based electrocatalysts for the ORR. The characteristics, ORR performance, and the related mechanism of these functionalized nanocarbons by heteroatom doping, defect inducing, and in particular their synergistic promotion effect are emphatically analyzed and discussed. Finally, the current issues and perspectives in developing carbon-based electrocatalysts from both of heteroatom doping and defect engineering are proposed. This review will be beneficial for the rational design and manufacturing of highly efficient carbon-based materials for electrocatalysis.

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