Chien-Liang Lee

Sonoelectrochemical intercalation and exfoliation for the preparation of defective graphene sheets and their application as nonenzymatic H2O2 sensors and oxygen reduction catalysts

A sonoelectrochemical synthetic method is reported for rapidly preparing and dispersing reduced graphene nanosheets (RGNSECM) stabilized in an aqueous electrolyte. The X-ray photoelectron and Raman results demonstrate that the defects on RGNSECM are predominantly physical and not similar to the chemical defects on reduced graphene nanosheets (RGNCM) synthesized via chemical reduction of graphene oxide nanosheets based on the Hummers method. The in-plane crystallite size (La) of RGNSECM is 26.8 nm, larger than the 18.2 nm of RGNCM. The RGNs prepared using the sonoelectrochemical method (RGNSECM) were successfully applied as nonenzymatic H2O2 sensors and alkaline oxygen reduction reaction (ORR) catalysts. Using electrochemical analysis, a fair comparison of the performances of RGNSECM and RGNCM as H2O2 sensors and ORR catalysts has been performed.

Hollow Ag/Pd triangular nanoplate: a novel activator for electroless nickel deposition.

Hollow Ag/Pd triangular nanoplates have been successfully prepared by a galvanic displacement reaction, in which added Pd(2+) ions react with Ag triangular nanoplates as templates. By altering the sizes of the Ag nanotemplates, Ag/Pd triangular nanoplates of different sizes can be prepared. Additionally, the large alloy nanoplates show maximum electrochemical activity when Ag/Pd triangular nanoplates of different sizes are applied as new activators for electroless nickel deposition.

High Activity of Hexagonal Ag/Pt Nanoshell Catalyst for Oxygen Electroreduction

Hexagonal Ag/Pt nanoshells were prepared by using a hexagonal Ag nanoplate as the displacement template and by introducing Pt ions. The prepared Ag/Pt nanoshells played the role of an electrocatalyst in an oxygen reduction process. Compared to spherical Pt and Ag/Pt nanoparticles, the hexagonal Ag/Pt nanoshells showed higher activity for oxygen electroreduction.

Synthesis of Highly Active Ag/Pd Nanorings for Activating Electroless Copper Deposition

A simple method for preparing Ag/Pd nanorings is reported. Energy dispersive X-ray element mapping results showed a random distribution of Ag and Pd atoms over the nanoring, indicating that the nanorings were made of an alloy of Ag and Pd. These nanorings were then successfully used as catalysts in electroless copper deposition. Results of quartz crystal microbalance measurements revealed that the catalytic activity of prepared Ag/Pd nanorings was better than that of monometallic Ag and Pd nanoparticles.

Activator for Electrolessly Depositing Copper from Triangular Ag∕Pd Nanoshells

This article reports that triangular Ag/Pd nanoshells are synthesized via the galvanic displacement reaction and further applied as activators for electroless copper deposition. Information as revealed by electrochemical quartz crystal microbalance, deposition rate catalyzed by the triangular Ag/Pd nanoshells is∼0.42 μg/cm 2 s and exhibit different electrochemical activity in the electroless deposition of copper.

Catalytic activity of Ag‐Pd nanoparticles prepared by N2H4 reduction in electroless nickel deposition

Abstract In this study we report on the catalytic activities of Ag/Pd alloy nanoparticles in electroless nickel deposition (END). The Ag/Pd nanoparticles were prepared by N2H4 reduction. Three types of Ag/Pd alloy nanoparticles were prepared from the simultaneous reduction of coexisting Ag and Pd ions in an aqueous solution of sodium dodecyl sulfate (SDS)/N2H4. The particle sizes of the three types of bimetallic nanoparticles in the SDS bath maintained at a controlled temperature were found to be near equal. The results of energy dispersive X‐ray and UV‐Vis spectroscopy measurements indicate that the distribution of Ag atoms in the structure of the bimetallic nanocatalysts increases with the CAg +/CPd 2+ ratio. Quartz crystal microgravimetry results reveal that the activities of the Ag10/Pd1, Ag1/Pd1, and Ag1/Pd10 nanoparticles are 2.55 × 10–3 cm‐2 . s‐1 1.0 × 10‐2 cm‐2 . s–1 and 3.04 × 10–3 cm‐2 . s‐1 respectively.

Electrostatic Preparation of Graphite Nanofiber-Supported Ag Nanoparticles

An electrostatic synthesis method was developed for preparing and decorating hexadecyltrimethylammonium-coated Ag nanoparticles at the sidewalls of sodium dodecyl sulfate micelle-functionalized herringbone graphite nariofibers (GNs). The results demonstrated the attachment of Ag nanoparticles to the GN surface via surfactant modification without the destruction, i.e., the preoxidation, of the GN surface structure. Further, as data supported by in situ analyses, the activity and electrochemical kinetics of the Ag/GN nanocomposite for electrocatalyzing oxygen reduction reaction (ORR) were studied. The numbers of ORR transfer electrons reached to 3.95, and the efficiency of H 2 O production was 95.27%. The result showed that this ORR occurred speedily.

A comparison of nitrogen-doped sonoelectrochemical and chemical graphene nanosheets as hydrogen peroxide sensors

Nitrogen-doped graphene nanosheet (N-SEGN) with pyrrolic nitrogen and 5-9 vacancy defects has been successfully prepared from a hydrothermal reaction of tetra-2-pyridinylpyrazine and sonoelectrochemistry-exfoliated graphene nanosheet, with point defects. Additionally, based on the same reaction using chemically reduced graphene oxide, nitrogen-doped chemically reduced graphene oxide (N-rGO) with graphitic nitrogen was prepared. The N-SEGN and N-rGO were used as a non-enzymatic H2O2 sensors. The sensitivity of the N-SEGN was 231.3 μA·mM-1·cm-2, much greater than 57.3 μA·mM-1·cm-2 of N-rGO. The N-SEGN showed their potential for being a H2O2 sensor.