Nanoporous PtCo Surface Alloy Architecture with Enhanced Properties for Methanol Electrooxidation

Abstract

By selectively dealloying a PtCoAl ternary alloy, a novel nanoporous PtCo (np-PtCo) alloy with a three-dimensional bicontinuous pore-ligament structure is successfully fabricated. X-ray diffraction and electron microscopic characterizations demonstrate the single-crystal nature of the alloy ligament with a ligament size down to ~3 nm. After a mild electrochemical dealloying process, a nanoporous near-surface alloy structure with a Pt-rich surface and a PtCo alloy core is obtained. Electrochemical measurements show that the np-PtCo surface alloy has greatly enhanced catalytic activity and durability toward methanol electrooxidation compared with a state-of-the-art Pt/C catalyst. The peak current density of methanol electrooxidation on a np-PtCo surface alloy is more than 5 times of that on Pt/C. More importantly, continuous potential cycling from 0.6 to 0.9 V (vs RHE) in a 0.5 M H(2)SO(4) aqueous solution demonstrates that a np-PtCo surface alloy has excellent structure stability, with more than 90% of the initial electrochemical active surface area (EASA) retained after 5000 potential cycles. Under the same conditions, the EASA of Pt/C drops to ~70%. With evident advantages of facile preparation as well as enhanced electrocatalytic activity and durability, a np-PtCo surface alloy nanomaterial holds great potential as an anode catalyst in direct methanol fuel cells.

Gold–platinum bimetallic nanotubes templated from tellurium nanowires as efficient electrocatalysts for methanol oxidation reaction

“…CO stripping voltammetry measurements were performed according to the previously reported procedure [28,29]. All the measurements were performed at room temperature with a scan rate of 50 mV s À1 .…”

Efficiently cubic platinum-cobalt bimetallic nano-catalysts for use in low-cost dye-sensitized solar cells

“…3I À . The relatively higher catalytic activity of Pt 3 Co CE could be owing to that the cubic Pt 3 Co has modified Pt electronic structure [23][24][25], Pt-rich and Pt-skin nano-structure with homogeneous morphology. The working mechanism of Pt 3 Co and PtCo CEs could be that the 3d transition metal Co is an electron-rich metal, which could supply electrons for Pt catalyst and enhance the electron density to accelerate the redox reaction of I 3 À + 2e À !…”

“…In especial, Pt alloying with relatively cheap transition metals (i.e. Fe, Co, Ni, Ru) shows an enhanced catalytic activity due to the modification of the Pt electronic structure as well as the correlation of the ligand and strain effects [23][24][25], which is widely used as the efficient catalyst for the oxygen reduction and methanol oxidation in the area of fuel cells [23][24][25][26][27]. Recently, Chen et al firstly prepared highly active Pt-Ni bimetallic nano-crystals in the oleylamine, which exhibited excellent oxygen reduction reaction activity due to both the interior and exterior catalytic surfaces of this three-dimensional open-framework structure were composed of the nanosegregated Pt-skin structure [28].…”

Preparation of Nanoporous Pd/CuO by Dealloying and Their Electrocatalysis for Methanol in Alkaline Condition

“…33 The size of the arc can reveal the kinetics of the methanol electrooxidation reaction. 34 The order of the semicircle diameters of the prepared catalysts is Ti 30 5 amorphous alloy would exhibit the lowest charge transfer resistance and the methanol oxidation occurs more easily. In addition, the charge transfer resistance decreases with the increase of CuO content, this indicates Pd : CuO ratio plays very important role in the electro-catalytic process and confirms the bifuntional mechanism of CuO.…”