scholarly journals Ultrahigh drive current and large selectivity in GeS selector

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Shujing Jia ◽  
Huanglong Li ◽  
Tamihiro Gotoh ◽  
Christophe Longeaud ◽  
Bin Zhang ◽  
...  
Keyword(s):  
Nonvolatile Memory ◽  
Large Scale ◽  
Chain Growth ◽  
Trap States ◽  
Drive Current ◽  
Threshold Switching ◽  
High Nonlinearity ◽  
High Drive ◽  
Earth Abundant ◽  
Silicon Transistor

Abstract Selector devices are indispensable components of large-scale nonvolatile memory and neuromorphic array systems. Besides the conventional silicon transistor, two-terminal ovonic threshold switching device with much higher scalability is currently the most industrially favored selector technology. However, current ovonic threshold switching devices rely heavily on intricate control of material stoichiometry and generally suffer from toxic and complex dopants. Here, we report on a selector with a large drive current density of 34 MA cm−2 and a ~106 high nonlinearity, realized in an environment-friendly and earth-abundant sulfide binary semiconductor, GeS. Both experiments and first-principles calculations reveal Ge pyramid-dominated network and high density of near-valence band trap states in amorphous GeS. The high-drive current capacity is associated with the strong Ge-S covalency and the high nonlinearity could arise from the synergy of the mid-gap traps assisted electronic transition and local Ge-Ge chain growth as well as locally enhanced bond alignment under high electric field.

scholarly journals Selective hydroboration of unsaturated bonds by an easily accessible heterotopic cobalt catalyst

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chuhan Li ◽  
Shuo Song ◽  
Yuling Li ◽  
Chang Xu ◽  
Qiquan Luo ◽  
...  
Keyword(s):  
Base Metal ◽  
Large Scale ◽  
Metal Cluster ◽  
Active Species ◽  
Cobalt Catalysts ◽  
Metal Salts ◽  
One Pot ◽  
Practical Utilization ◽  
Earth Abundant

AbstractHomogeneous earth-abundant metal catalysis based on well-defined molecular complexes has achieved great advance in synthetic methodologies. However, sophisticated ligand, hazardous activator and multistep synthesis starting from base metal salts are generally required for the generation of active molecular catalysts, which may hinder their broad application in large scale organic synthesis. Therefore, the development of metal cluster catalysts formed in situ from simple earth-abundant metal salts is of importance for the practical utilization of base metal resource, yet it is still in its infancy. Herein, a mixture of catalytic amounts of cobalt (II) iodide and potassium tert-butoxide is discovered to be highly active for selective hydroboration of vinylarenes and dihydroboration of nitriles, affording a good yield of diversified hydroboration products that without isolation can readily undergo further one pot transformations. It should be highlighted that the alkoxide-pinacolborane combination acts as an efficient activation strategy to activate cobalt (II) iodide for the generation of metastable heterotopic cobalt catalysts in situ, which is proposed to be catalytically active species.

scholarly journals WS(1−x)Sex Nanoparticles Decorated Three-Dimensional Graphene on Nickel Foam: A Robust and Highly Efficient Electrocatalyst for the Hydrogen Evolution Reaction

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 929 ◽  
Author(s):  
Sajjad Hussain ◽  
Kamran Akbar ◽  
Dhanasekaran Vikraman ◽  
Rana Afzal ◽  
Wooseok Song ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Large Scale ◽  
Nickel Foam ◽  
Transition Metal Dichalcogenides ◽  
Three Dimensional ◽  
Cost Effective ◽  
Highly Efficient ◽  
Highly Active ◽  
Earth Abundant

To find an effective alternative to scarce, high-cost noble platinum (Pt) electrocatalyst for hydrogen evolution reaction (HER), researchers are pursuing inexpensive and highly efficient materials as an electrocatalyst for large scale practical application. Layered transition metal dichalcogenides (TMDCs) are promising candidates for durable HER catalysts due to their cost-effective, highly active edges and Earth-abundant elements to replace Pt electrocatalysts. Herein, we design an active, stable earth-abundant TMDCs based catalyst, WS(1−x)Sex nanoparticles-decorated onto a 3D porous graphene/Ni foam. The WS(1−x)Sex/graphene/NF catalyst exhibits fast hydrogen evolution kinetics with a moderate overpotential of ~−93 mV to drive a current density of 10 mA cm−2, a small Tafel slope of ~51 mV dec−1, and a long cycling lifespan more than 20 h in 0.5 M sulfuric acid, which is much better than WS2/NF and WS2/graphene/NF catalysts. Our outcomes enabled a way to utilize the TMDCs decorated graphene and precious-metal-free electrocatalyst as mechanically robust and electrically conductive catalyst materials.

scholarly journals Atomically dispersed nickel as coke-resistant active sites for methane dry reforming

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohcin Akri ◽  
Shu Zhao ◽  
Xiaoyu Li ◽  
Ketao Zang ◽  
Adam F. Lee ◽  
...  
Keyword(s):  
Active Sites ◽  
Large Scale ◽  
Low Cost ◽  
Coke Formation ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Highly Active ◽  
Catalytic Sites ◽  
Earth Abundant ◽  
Poor Stability

AbstractDry reforming of methane (DRM) is an attractive route to utilize CO2 as a chemical feedstock with which to convert CH4 into valuable syngas and simultaneously mitigate both greenhouse gases. Ni-based DRM catalysts are promising due to their high activity and low cost, but suffer from poor stability due to coke formation which has hindered their commercialization. Herein, we report that atomically dispersed Ni single atoms, stabilized by interaction with Ce-doped hydroxyapatite, are highly active and coke-resistant catalytic sites for DRM. Experimental and computational studies reveal that isolated Ni atoms are intrinsically coke-resistant due to their unique ability to only activate the first C-H bond in CH4, thus avoiding methane deep decomposition into carbon. This discovery offers new opportunities to develop large-scale DRM processes using earth abundant catalysts.

NATURE-LIKE PHOTOSYNTHESIS OF WATER AND CARBON DIOXIDE WITH FEMTOSECOND LASER INDUCED SELF-ASSEMBLED METAL NANOSTRUCTURES

2009 ◽  
Vol 23 (31) ◽  
pp. 5849-5857 ◽  
Author(s):  
CONG WANG ◽  
MENGYAN SHEN ◽  
HAIBIN HUO ◽  
HAIZHOU REN ◽  
FADONG YAN ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Solar Energy ◽  
Femtosecond Laser ◽  
Large Scale ◽  
Metal Nanostructures ◽  
Surface Enhanced ◽  
Earth Abundant ◽  
Metal Nanostructure ◽  
Nanostructure Arrays ◽  
Self Assembled

Large-scale replication of the natural process of photosynthesis is a crucial subject of storing solar energy and saving our environment. Here, we report femtosecond laser induced self-assembled metal nanostructure arrays, which are easily mass producible on earth-abundant metals, can directly synthesize liquid and solid hydrocarbon compounds from carbon dioxide, water, and sunlight at a production rate of more than 1 × 105 μ L/(gh) that is significantly (103–106 times) higher than those in previous studies.1,2 The efficiency for storing solar energy of the photosynthesis is about 10% in the present simple experimental setup which can be further improved. Moreover, different from previous artificial photosynthesis works, this phenomenon presents a new mechanism that, through a surface-enhanced photodissociation process, nature-like photosynthesis can be performed artificially.

scholarly journals Efficient solar-to-fuels production from a hybrid microbial–water-splitting catalyst system

2015 ◽  
Vol 112 (8) ◽  
pp. 2337-2342 ◽  
Author(s):  
Joseph P. Torella ◽  
Christopher J. Gagliardi ◽  
Janice S. Chen ◽  
D. Kwabena Bediako ◽  
Brendan Colón ◽  
...  
Keyword(s):  
Water Splitting ◽  
Large Scale ◽  
Ralstonia Eutropha ◽  
Catalyst System ◽  
Liquid Fuels ◽  
Terrestrial Plants ◽  
Energy Current ◽  
Fusel Alcohols ◽  
Energy Needs ◽  
Earth Abundant

Photovoltaic cells have considerable potential to satisfy future renewable-energy needs, but efficient and scalable methods of storing the intermittent electricity they produce are required for the large-scale implementation of solar energy. Current solar-to-fuels storage cycles based on water splitting produce hydrogen and oxygen, which are attractive fuels in principle but confront practical limitations from the current energy infrastructure that is based on liquid fuels. In this work, we report the development of a scalable, integrated bioelectrochemical system in which the bacterium Ralstonia eutropha is used to efficiently convert CO2, along with H2 and O2 produced from water splitting, into biomass and fusel alcohols. Water-splitting catalysis was performed using catalysts that are made of earth-abundant metals and enable low overpotential water splitting. In this integrated setup, equivalent solar-to-biomass yields of up to 3.2% of the thermodynamic maximum exceed that of most terrestrial plants. Moreover, engineering of R. eutropha enabled production of the fusel alcohol isopropanol at up to 216 mg/L, the highest bioelectrochemical fuel yield yet reported by >300%. This work demonstrates that catalysts of biotic and abiotic origin can be interfaced to achieve challenging chemical energy-to-fuels transformations.

Gate-All-Around (GAA) Fully Depleted (FD) Cantilever Channel MOSFET with High-k Dielectric and Metal Gate

2007 ◽  
Vol 995 ◽  
Author(s):  
Sagnik Dey ◽  
Se-Hoon Lee ◽  
Sachin V. Joshi ◽  
Prashant Majhi ◽  
Sanjay K. Banerjee
Keyword(s):  
Metal Gate ◽  
Leakage Currents ◽  
Drive Current ◽  
Fully Depleted ◽  
Low Leakage ◽  
High Drive ◽  
High K ◽  
High K Dielectric

AbstractA MOSFET formed by a Si cantilever channel suspended between source/drain “anchors” wrapped all-around by high-κ dielectric and metal gate is demonstrated. The device shows excellent subthreshold characteristics and low leakage currents due to the fully depleted body and the gate-all-around architecture implemented with a high-κ dielectric and metal gate. At the same time this also allows a high drive current due to mobility enhancements arising from volume inversion of the cantilever channel such that a large ION/IOFF is achieved.

Analysis of the threshold switching mechanism of a Te–SbO selector device for crosspoint nonvolatile memory applications

2017 ◽  
Vol 111 (18) ◽  
pp. 183501 ◽  
Author(s):  
Young Seok Kim ◽  
Ji Woon Park ◽  
Jong Ho Lee ◽  
In Ah Choi ◽  
Jaeyeong Heo ◽  
...  
Keyword(s):  
Nonvolatile Memory ◽  
Switching Mechanism ◽  
Threshold Switching ◽  
Memory Applications
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