Tailoring the Structure and Property of Pt-Decorated Nanoporous Gold by Thermal Annealing

Abstract

We study the structure evolution of a novel electrocatalyst, Pt-decorated nanoporous gold (Pt-NPG), during thermal annealing at relatively low temperatures. Pt-NPG was made by plating a thin layer of Pt over NPG substrate during an electroless plating process that generated epitaxial Pt nanoislands loaded on the NPG surface. In comparison with Pt’s very high melting point, thermal annealing at temperatures as low as 100 °C was found to significantly change the structure and surface chemistry of these nanomaterials. Scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical techniques were combined to characterize the structures of Pt-NPG annealed under various conditions. While Pt-NPG preserved very well its initial porous morphology, the deposited Pt islands collapsed to form a thin Au−Pt alloy layer coating on the NPG surface upon heating. This structure change results in severe modulation to the electronic structure and surface reactivity of Pt, which were proved by markedly different behaviors in electrocatalytic reactions such as formic acid electro-oxidation and CO stripping. These findings provide considerable insight into the Au−Pt bimetallic system and pave the way for the application of Pt-NPG in fuel cell technologies.

Electrochemical catalytic activities of nanoporous palladium rods for methanol electro-oxidation

“…3(d)-(f)) becomes more and more obvious. It is well known that the stripping peak profile is sensitive to the composition and microstructure of metal particles [30], and several studies have found that the CO stripping curves associated with the Au-Pt [31,32], Pd-Ag [33], Pd-Ir [34], and Pt-Ru-P [35], will exhibit a contour change by variating the amount of the additive elements. Thus, the appearing shoulder peak may be caused by the existing residual Al in the Pd rods ( Fig.…”

Polyethyleneimine-assisted synthesis of high-quality platinum/graphene hybrids: the effect of molecular weight on electrochemical properties

“…21,22 The weak peak O 1 at 0.55 V and the strong peak O 2 at 0.9 V on the Pt/C electrocatalyst correspond to the direct dehydrogenation oxidation and indirect dehydration oxidation of formic acid, respectively (Fig. [27][28][29][30][31][32][33][34][35][36][37][38][39] The isolated Pt atom facilitates the direct dehydrogenation pathway of the FAOR (i.e., the ensemble effect). The ratio of the two peak currents (IO 1 /IO 2 ) is calculated to be 0.22, indicating that the FAOR on the Pt/C electrocatalyst occurs mainly through the indirect dehydration pathway.…”

Three-dimensional porous Au nanocoral structure decorated with Pt submonolayer via galvanic displacement of copper adatoms for electrooxidation of formic acid

“…The enhanced electrocatlytic activity of Pt n /GNN composites is attributed to the domination of the direct oxidation of formic acid [23,25]. Cuesta et al [20] demonstrated that the direct oxidation of formic acid does not involve the adsorption of CO by using ATR-SEIRAS and HCOO ad is directly oxidized to CO 2 , which explains why Pt n /GNN composites have better stabilities than Pt/C, as shown in Fig.…”