The Experts below are selected from a list of 13926 Experts worldwide ranked by ideXlab platform
Raymond E. Schaak - One of the best experts on this subject based on the ideXlab platform.
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general strategy for the synthesis of transition metal Phosphide films for electrocatalytic hydrogen and oxygen evolution
ACS Applied Materials & Interfaces, 2016Co-Authors: Carlos G Read, Juan F Callejas, Cameron F Holder, Raymond E. SchaakAbstract:Transition metal Phosphides recently have been identified as promising Earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Here, we present a general and scalable strategy for the synthesis of transition metal Phosphide electrodes based on the reaction of commercially available metal foils (Fe, Co, Ni, Cu, and NiFe) with various organophosphine reagents. The resulting Phosphide electrodes were found to exhibit excellent electrocatalytic HER and OER performance. The most active electrodes required overpotentials of only −128 mV for the HER in acid (Ni2P), −183 mV for the HER in base (Ni2P), and 277 mV for the OER in base (NiFeP) to produce operationally relevant current densities of 10 mA cm–2. Such HER and OER performance compares favorably with samples prepared using significantly more elaborate and costly procedures. Furthermore, we demonstrate that the approach can also be utilized to obtain highly active and conformal metal Phosphide coati...
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converting metals into Phosphides a general strategy for the synthesis of metal Phosphide nanocrystals
Journal of the American Chemical Society, 2007Co-Authors: Amanda E. Henkes, Yolanda Vasquez, Raymond E. SchaakAbstract:Nanocrystals of metal Phosphides, which can have useful catalytic, electronic, and magnetic properties, are known to be accessible by using trioctylphosphine (TOP) as a highly reactive phosphorus source. Here we report a general strategy for synthesizing transition metal Phosphides, including those with 4d and 5d transition metals that have not previously been reported as unsupported nanocrystals. Unlike previously reported methods that involve direct decomposition of organometallic precursors, our method utilizes preformed metal nanoparticles as templates for generating metal Phosphide nanocrystals. Metal nanoparticles are reacted with TOP in a hot solvent (290−360 °C) to form transition metal Phosphides such as Ni2P, PtP2, Rh2P, PdP2, Pd5P2, and Au2P3. Furthermore, nanostructures such as hollow spheres can be easily made using a Kirkendall-type mechanism, which utilizes metal nanoparticles as reactive templates.
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Trioctylphosphine: A General Phosphorus Source for the Low-Temperature Conversion of Metals into Metal Phosphides
Chemistry of Materials, 2007Co-Authors: Amanda E. Henkes, Raymond E. SchaakAbstract:Metal Phosphides can have important properties such as superconductivity, magnetoresistance, magnetocaloric behavior, catalytic activity, and lithium intercalation capacity, which make them useful for a variety of technological applications. Bulk metal Phosphides usually require high temperatures and harsh reaction conditions to form, and metal Phosphide nanocrystals can also be challenging to synthesize. Here we elaborate on a recently developed alternative approach for synthesizing metal Phosphides, which involves the solution-mediated reaction of pre-formed metals with trioctylphosphine (TOP) at temperatures below 370 °C. This chemical conversion strategy is shown to be general and highly versatile, successfully forming a wide range of transition-metal and post-transition-metal Phosphides using a range of both bulk and nanoscale metals as precursors. Metal nanocrystals, bulk powders, foils, wires, thin films, lithographically patterned substrates, and supported nanocrystals can all be converted to meta...
Amanda E. Henkes - One of the best experts on this subject based on the ideXlab platform.
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converting metals into Phosphides a general strategy for the synthesis of metal Phosphide nanocrystals
Journal of the American Chemical Society, 2007Co-Authors: Amanda E. Henkes, Yolanda Vasquez, Raymond E. SchaakAbstract:Nanocrystals of metal Phosphides, which can have useful catalytic, electronic, and magnetic properties, are known to be accessible by using trioctylphosphine (TOP) as a highly reactive phosphorus source. Here we report a general strategy for synthesizing transition metal Phosphides, including those with 4d and 5d transition metals that have not previously been reported as unsupported nanocrystals. Unlike previously reported methods that involve direct decomposition of organometallic precursors, our method utilizes preformed metal nanoparticles as templates for generating metal Phosphide nanocrystals. Metal nanoparticles are reacted with TOP in a hot solvent (290−360 °C) to form transition metal Phosphides such as Ni2P, PtP2, Rh2P, PdP2, Pd5P2, and Au2P3. Furthermore, nanostructures such as hollow spheres can be easily made using a Kirkendall-type mechanism, which utilizes metal nanoparticles as reactive templates.
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Trioctylphosphine: A General Phosphorus Source for the Low-Temperature Conversion of Metals into Metal Phosphides
Chemistry of Materials, 2007Co-Authors: Amanda E. Henkes, Raymond E. SchaakAbstract:Metal Phosphides can have important properties such as superconductivity, magnetoresistance, magnetocaloric behavior, catalytic activity, and lithium intercalation capacity, which make them useful for a variety of technological applications. Bulk metal Phosphides usually require high temperatures and harsh reaction conditions to form, and metal Phosphide nanocrystals can also be challenging to synthesize. Here we elaborate on a recently developed alternative approach for synthesizing metal Phosphides, which involves the solution-mediated reaction of pre-formed metals with trioctylphosphine (TOP) at temperatures below 370 °C. This chemical conversion strategy is shown to be general and highly versatile, successfully forming a wide range of transition-metal and post-transition-metal Phosphides using a range of both bulk and nanoscale metals as precursors. Metal nanocrystals, bulk powders, foils, wires, thin films, lithographically patterned substrates, and supported nanocrystals can all be converted to meta...
Alexey Shavel - One of the best experts on this subject based on the ideXlab platform.
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Triphenyl Phosphite as the Phosphorus Source for the Scalable and Cost-Effective Production of Transition Metal Phosphides
Chemistry of Materials, 2018Co-Authors: Junfeng Liu, Michaela Meyns, Ting Zhang, Jordi Arbiol, Andreu Cabot, Alexey ShavelAbstract:Transition metal Phosphides have great potential to optimize a number of functionalities in several energy conversion and storage applications, particularly when nanostructured or in nanoparticle form. However, the synthesis of transition metal Phosphide nanoparticles and its scalability is often limited by the toxicity, air sensitivity, and high cost of the reagents used. We present here a simple, scalable, and cost-effective “heating up” procedure to produce metal Phosphides using inexpensive, low-toxicity, and air-stable triphenyl phosphite as source of phosphorus and chlorides as metal precursors. This procedure allows the synthesis of a variety of Phosphide nanoparticles, including Phosphides of Ni, Co, and Cu. The use of carbonyl metal precursors further allowed the synthesis of Fe2P and MoP nanoparticles. The fact that minor modifications in the experimental parameters allowed producing nanoparticles with different compositions and even to tune their size and shape shows the high potential and vers...
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Triphenyl Phosphite as the Phosphorus Source for the Scalable and Cost-Effective Production of Transition Metal Phosphides
2018Co-Authors: Junfeng Liu, Michaela Meyns, Ting Zhang, Jordi Arbiol, Andreu Cabot, Alexey ShavelAbstract:Transition metal Phosphides have great potential to optimize a number of functionalities in several energy conversion and storage applications, particularly when nanostructured or in nanoparticle form. However, the synthesis of transition metal Phosphide nanoparticles and its scalability is often limited by the toxicity, air sensitivity, and high cost of the reagents used. We present here a simple, scalable, and cost-effective “heating up” procedure to produce metal Phosphides using inexpensive, low-toxicity, and air-stable triphenyl phosphite as source of phosphorus and chlorides as metal precursors. This procedure allows the synthesis of a variety of Phosphide nanoparticles, including Phosphides of Ni, Co, and Cu. The use of carbonyl metal precursors further allowed the synthesis of Fe2P and MoP nanoparticles. The fact that minor modifications in the experimental parameters allowed producing nanoparticles with different compositions and even to tune their size and shape shows the high potential and versatility of the triphenyl phosphite precursor and the presented method. We also detail here a methodology to displace organic ligands from the surface of Phosphide nanoparticles, which is a key step toward their application in energy conversion and storage systems
Roel Prins - One of the best experts on this subject based on the ideXlab platform.
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Metal Phosphides: Preparation, Characterization and Catalytic Reactivity
Catalysis Letters, 2012Co-Authors: Roel Prins, Mark E. BussellAbstract:The preparation, characterization, and catalytic activity of supported metal Phosphides are reviewed. Reduction of metal compounds together with phosphate is a convenient method to prepare metal Phosphides, but requires high temperature. Reduction with phosphite, hypophosphite, or phosphine and the plasma reduction of phosphate can be carried out at lower temperatures, which leads to smaller metal Phosphide particles and more active catalysts. Organometallic routes allow the separate synthesis of metal Phosphide nanoparticles, which have to be added to the support in a second step. LEED, STM, XPS, and DFT studies have shown that the surfaces of Ni_2P reconstruct to P-rich surfaces. The investigation of metal Phosphides as catalysts for hydrotreating reactions continues to be a topic of considerable research with recent advances realized in using bimetallic and noble metal Phosphides to achieve high activities and tailored selectivities. Finally, hydrodeoxygenation catalysis over metal Phosphides is a growing area of research given the need to develop catalysts for upgrading biomass to transportation fuels. Graphical Abstract
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new synthesis method for nickel Phosphide hydrotreating catalysts
Chemical Communications, 2005Co-Authors: Shaofeng Yang, Roel PrinsAbstract:Nickel Phosphide particles on silica and alumina support were prepared from metal or metal oxide particles by treatment with phosphine and hydrogen at moderate temperature, resulting in small particle sizes equivalent to that of the precursor particle size.
Paul R Ebert - One of the best experts on this subject based on the ideXlab platform.
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resistance to the fumigant phosphine and its management in insect pests of stored products a global perspective
Annual Review of Entomology, 2020Co-Authors: Manoj K Nayak, Gregory J Daglish, Thomas W Phillips, Paul R EbertAbstract:Development of resistance in major grain insect pest species to the key fumigant phosphine (hydrogen Phosphide) across the globe has put the viability and sustainability of phosphine in jeopardy. The resistance problem has been aggravated over the past two decades, due mostly to the lack of suitable alternatives matching the major attributes of phosphine, including its low price, ease of application, proven effectiveness against a broad pest spectrum, compatibility with most storage conditions, and international acceptance as a residue-free treatment. In this review, we critically analyze the published literature in the area of phosphine resistance with special emphasis on the methods available for detection of resistance, the genetic basis of resistance development, key management strategies, and research gaps that need to be addressed.
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Comparative Toxicity of Fumigants and a Phosphine Synergist Using a Novel Containment Chamber for the Safe Generation of Concentrated Phosphine Gas
2013Co-Authors: Nicholas Valmas, Paul R EbertAbstract:Background. With the phasing out of ozone-depleting substances in accordance with the United Nations Montreal Protocol, phosphine remains as the only economically viable fumigant for widespread use. However the development of high-level resistance in several pest insects threatens the future usage of phosphine; yet research into phosphine resistance mechanisms has been limited due to the potential for human poisoning in enclosed laboratory environments. Principal Findings. Here we describe a custom-designed chamber for safely containing phosphine gas generated from aluminium Phosphide tablets. In an improvement on previous generation systems, this chamber can be completely sealed to control the escape of phosphine. The device has been utilised in a screening program with C. elegans that has identified a phosphine synergist, and quantified the efficacy of a new fumigant against that of phosphine. The phosphine-induced mortality at 20uC has been determined with an LC50 of 732 ppm. This result was contrasted with the efficacy of a potential new botanical pesticide dimethyl disulphide, which for a 24 hour exposure at 20uC is 600 times more potent than phosphine (LC 50 1.24 ppm). We also found that co-administration of the glutathione depletor diethyl maleate (DEM) with a sublethal dose of phosphine (70 ppm,,LC5), results in a doubling of mortality in C. elegans relative to DEM alone. Conclusions. The prohibitive danger associated with the generation, containment, and use of phosphine in a laboratory environment has now been substantially reduced by the implementation of our novel gas generation chamber. We have also identified a novel phosphine synergist, the glutathione depletor DEM, suggesting an effective pathway to be targeted in future synergist research; as well as quantifying the efficacy of a potentia
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comparative toxicity of fumigants and a phosphine synergist using a novel containment chamber for the safe generation of concentrated phosphine gas
PLOS ONE, 2006Co-Authors: Nicholas Valmas, Paul R EbertAbstract:Background. With the phasing out of ozone-depleting substances in accordance with the United Nations Montreal Protocol, phosphine remains as the only economically viable fumigant for widespread use. However the development of high-level resistance in several pest insects threatens the future usage of phosphine; yet research into phosphine resistance mechanisms has been limited due to the potential for human poisoning in enclosed laboratory environments. Principal Findings. Here we describe a custom-designed chamber for safely containing phosphine gas generated from aluminium Phosphide tablets. In an improvement on previous generation systems, this chamber can be completely sealed to control the escape of phosphine. The device has been utilised in a screening program with C. elegans that has identified a phosphine synergist, and quantified the efficacy of a new fumigant against that of phosphine. The phosphine-induced mortality at 20°C has been determined with an LC of 732 ppm. This result was contrasted with the efficacy of a potential new botanical pesticide dimethyl disulphide, which for a 24 hour exposure at 20°C is 600 times more potent than phosphine (LC 1.24 ppm). We also found that co-administration of the glutathione depletor diethyl maleate (DEM) with a sublethal dose of phosphine (70 ppm,
