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Xiangrong Ye

Bio: Xiangrong Ye is an academic researcher from University of Idaho. The author has contributed to research in topics: Supercritical fluid & Supercritical carbon dioxide. The author has an hindex of 5, co-authored 8 publications receiving 314 citations. Previous affiliations of Xiangrong Ye include Pacific Northwest National Laboratory & Environmental Molecular Sciences Laboratory.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the electrocatalytic reactivity of palladium-modified carbon nanotubes (Pd-CNTs) for the oxygen reduction reaction (ORR) was investigated at the glassy carbon electrode surface in 1M H2SO4 saturated by oxygen.

140 citations

Journal ArticleDOI
TL;DR: A low temperature carbon dioxide based on immersion deposition technology (SFID) has been developed for producing palladium, copper, silver, and other metal films on silicon-based substrates in supercritical CO2 as mentioned in this paper.
Abstract: A low temperature carbon dioxide based on immersion deposition technology (SFID) has been developed for producing palladium, copper, silver, and other metal films on silicon-based substrates in supercritical CO2. The reaction is initiated by oxidation of elemental silicon to SiF4 or H2SiF6 by HF with the release of electrons that cause the reduction of metal ions in an organometallic precursor to the metallic form on silicon surface in CO2. Only the substrate surfaces are coated with metals using this method. Based on surface analysis of the films and spectroscopic analysis of the reaction products, the mechanism of metal film deposition is discussed. The metal films (Pd, Cu, and Ag) formed on silicon surfaces by the SFID method exhibit good coverage, smooth and dense texture, high purity and a metallic behavior. Similarly, metal films can also be deposited onto geranium substrates using SFID. The gas-like properties and the high pressure of the supercritical fluids, combined with the low reaction temperature, make this SFID method potentially useful for depositing thin metal films in small features, which are difficult to accomplish by conventional CVD methods.

72 citations

Journal ArticleDOI
TL;DR: Using supercritical or near-supercritical fluids as media for physical or chemical transformations is an emerging technology for nanomaterials production as discussed by the authors, and the unusual properties of supercritical fl...
Abstract: Using supercritical or near-supercritical fluids as media for physical or chemical transformations is an emerging technology for nanomaterials production. The unusual properties of supercritical fl...

65 citations

Patent
21 Jan 2005
TL;DR: In this paper, the authors describe a method to transport a metal, metallic compound or precursor to a surface of a nanostructure substrate in a carrier while the carrier is in supercritical fluid form.
Abstract: Embodiments of nanostructures and nanocomposites and embodiments of methods for forming and modifying these nanostructures and nanocomposites are disclosed. The methods can include transporting a metal, metallic compound or precursor to a surface of a nanostructure substrate in a carrier while the carrier is in supercritical fluid form. Embodiments of the disclosed methods can be used to form catalytic structures, such as catalytic structures including nanostructure supports and catalytic metallic nanoparticles attached to the nanostructure supports. These catalytic structures are useful for catalyzing reactions in fuel cell applications, such as oxygen reduction and methanol oxidation reactions. Some of the disclosed nanostructures and nanocomposites include carbon nanotubes.

29 citations

Journal ArticleDOI
TL;DR: In this paper, the components of supercritical fluid immersion deposition (SFID) solutions for fabricating Cu and Pd films on silicon substrates are described along with the corresponding experimental setup and procedures.
Abstract: Supercritical CO 2 is used as a new solvent for immersion deposition, a galvanic displacement process traditionally carried out in aqueous HF solutions containing metal ions, to selectively develop metal films on silicon substrates. Components of supercritical fluid immersion deposition (SFID) solutions for fabricating Cu and Pd films on silicon substrates are described along with the corresponding experimental setup and procedures. Through this method, only silicon surfaces exposed to SFID solutions can be coated. The highly pressurized and gas-like supercritical CO 2 , combined with the galvanic displacement property of immersion deposition, enables the SFID technique to deposit metal films selectively in small features. Annealing of thin palladium films deposited by SFID can lead to the formation of palladium silicide in small features on silicon substrates.

11 citations


Cited by
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Journal ArticleDOI
TL;DR: Graphene has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production).
Abstract: Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphenebased enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.

2,866 citations

Journal ArticleDOI
Bin Wang1
TL;DR: In this paper, a review of the electrochemical slow oxygen reduction reaction (ORR) on non-Pt catalysts, especially the experimental development during the past five years, is presented.

781 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarized several important kinds of novel support materials for PEM fuel cells (including direct methanol fuel cells): nanostructured carbon materials (carbon nanotubes, carbon nanofibers, mesoporous carbon), conductive doped diamonds and nanodiamonds, conductive oxides (tin oxide/indium tin oxide, titanium oxide, tungsten oxide), and carbides (tungsten carbides).
Abstract: Catalyst support materials exhibit great influence on the cost, performance, and durability of polymer electrolyte membrane (PEM) fuel cells. This feature article summarizes several important kinds of novel support materials for PEM fuel cells (including direct methanol fuel cells): nanostructured carbon materials (carbon nanotubes, carbon nanofibers, mesoporous carbon), conductive doped diamonds and nanodiamonds, conductive oxides (tin oxide/indium tin oxide, titanium oxide, tungsten oxide), and carbides (tungsten carbides). The advantages and disadvantages, the acting mechanism to promote electrocatalytic performance, and the strategies to improve present catalyst support materials and search for new ones are discussed. This is expected to shed light on future development of catalyst supports for PEM fuel cells.

585 citations

Journal ArticleDOI
TL;DR: In this article, a review of different methods of nanoparticle preparations and its advantages, disadvantages, and applications is presented, which is categorized into two main types on as bottom up methods and top down methods depending on starting material of nanoparticles preparation.

573 citations

Journal ArticleDOI
TL;DR: A review of recent developments on particle formation from polymers using supercritical fluids has been reviewed with an emphasis on articles published during 2000-2003 as discussed by the authors, focusing on the production of polymer particles that contain active ingredients.
Abstract: Recent developments on particle formation from polymers using supercritical fluids have been reviewed with an emphasis on articles published during 2000–2003. First, a brief description of the basic operating principles of the various particle formation processes is presented. These include the rapid expansion of supercritical solutions (RESS), the gas antisolvent process (GAS), supercritical antisolvent process (SAS) and its various modifications, and the particles from gas-saturated solution (PGSS) processes. An account of the general review articles that have been published in previous years is then provided. The publications that have appeared over the past 4 years have been reviewed under two groupings, one involving the production of particles from pure polymers, and the other involving the production of polymer particles that contain active ingredients, especially those that pertain to pharmaceuticals. The majority of the efforts in the current supercritical particle formation technology is indeed on the production of polymer particles that are of pharmaceutical significance. In each grouping, the publications were further categorized according to the primary role played by the supercritical fluid in the process, namely whether it was used as a solvent, or as an antisolvent, or as a solute. This review is the first comprehensive review specifically focused on the formation of particles from polymers.

561 citations