Showing papers by "Na Tian published in 2009"
TL;DR: It is demonstrated that the developed square-wave potential method has surmounted the limit of conventional chemical methods that could synthesize merely metal nanocrystals with low surface energy, and opened a new prospect avenue in shape-controlled synthesis of nanoparticle catalysts with high surface energy and enhanced activity.
Abstract: Electrochemical shape-controlled synthesis of metal nanocrystal (NC) catalysts bounded by high-index facets with high surface energy was achieved by developing a square-wave potential route. Tetrahexahedral Pt NCs with 24 {hk0} facets, concave hexoctahedral Pt NCs with 48 {hkl} facets, and multiple twinned Pt nanorods with {hk0} facets were produced. The method was employed also to synthesize successfully trapezohedral Pd NCs with 24 {hkk} facets, and concave hexoctahedral Pd NCs with 48 {hkl} facets. It has been tested that, thanks to the high-index facets with high density of atomic steps and dangling bonds, the tetrahexahedral Pt NCs exhibit much enhanced catalytic activity for equivalent Pt surface areas for electrooxidation of small organic fuels such as ethanol. These results demonstrate that the developed square-wave potential method has surmounted the limit of conventional chemical methods that could synthesize merely metal nanocrystals with low surface energy, and opened a new prospect avenue in shape-controlled synthesis of nanoparticle catalysts with high surface energy and enhanced activity.
167 citations
TL;DR: Fivefold twinned Pd nanorods bounded by high-index facets of {hk0} or {hkk} were prepared by an electrochemical method and tested as electrocatalysts of high activity for ethanol oxidation.
150 citations
TL;DR: The Natural Science Foundation of China as discussed by the authors [20673091, 20433060, 20503023, 20873113, 20833005], Mnistry of Science and Technology of China [2009CB220102, 2007DFA40890]
Abstract: Natural Science Foundation of China [20673091, 20433060, 20503023, 20873113, 20833005]; Mnistry of Science and Technology of China [2009CB220102, 2007DFA40890]
62 citations
TL;DR: In this article, the authors studied the kinetics of dissociative adsorption of formic acid on the electrode of tetrahexahedral platinum nanocrystals (THH Pt NCs).
Abstract: In the present paper we study the kinetics of dissociative adsorption of formic acid on the electrode of tetrahexahedral platinum nanocrystals (THH Pt NCs). In situ FTIR spectroscopic results demonstrate that HCOOH can be oxidized to CO2 at a low potential (−0.2 V(SCE)) on the THH Pt NCs electrode, and the chemical bonds inside formic acid molecule are broken to form adsorbed COL species. The kinetics of the dissociative adsorption of HCOOH was quantitatively investigated by employing programmed potential step technique. It has been determined that, in 5 × 10−3 mol·L−1 HCOOH + 0.1 mol·L−1 H2SO4 solution, the maximal value of the average rate (υ
a
max
) of dissociative adsorption of HCOOH on a commercial Pt/C catalyst electrode is 8.58 × 10−10 mol·cm−2·s−1, while on the THH Pt NCs the υ
a
max
is 1.5 times larger than the υ
a
max
measured on Pt/C and reaches 13.19 × 10−10 mol·cm−2·s−1. The results have revealed that the reactivity of the THH Pt NCs is much higher than that of the Pt/C catalysts.
3 citations