3D Nanoporous Gold with Very Low Parting Limit Derived from Au‐Based Metallic Glass and Enhanced Methanol Electro‐oxidation Catalytic Performance Induced by Metal Migration

Abstract

Nanoporousg old (NPG) with bi-continuous ligaments and pores structure has promising potential in functional applications, among which one prominente xample is fuel cell electrocatalysts. However,c urrent application of NPG is mostly limited to methanole lectro-oxidation (MOR) due to its weakc atalytic performance. Here we report a simple chemical dealloying process for generating peculiar three-dimensional (3D) free-standing NPG with 'parting limit' as low as 25 %( lowert han theoretical 'paringl imit' 55 %) and high specific surface area (maximum % 31 m 2 g À1 )a ssociated with an ovel porous 'cone shaped protrusion' morphol-ogy.T his NPG structure possesses the highest specific activity of MOR catalytic performance reported NPG catalysts so far.I na ddition, taking advantage of this excellent structural feature of the NPG, an anoporous Pd catalyst( NPG@Pd) thin film was fabricated on the NPG substrate. The NPG@Pd catalyst exhibited greatly enhancedM OR performance (maximum MOR specific activity 2.14 mA cm À2 ). We attribute the enhancement of MOR activity to the increase of active sites as well as the modification of surfacec omposition and electronic structure due to migration of Au to the Pd thin film layer.

Nanoporous Quasi-High-Entropy Alloy Microspheres

“…In this work, the standard equilibrium electrode potential of Cu is much lower than that of Au, Pt, and Pd [38][39][40], which offers a great driving force for the selective dissolution of Cu under free-dealloying conditions. After dealloying for 24 h, the ratio of remaining Cu and the other three elements is nearly equal, and the calculated physical parameters in Table 1 satisfy the empirical Further analysis by TEM (Figure 7a,b) reveals a nanoscale bicontinuous ligament/pore structure inside the grains, in which the ligament width and pore sizes are~12 nm and~9 nm, respectively.…”

“…Moreover, the work may stimulate the overall development of quasi-HEAs in various chemical applications. In this work, the standard equilibrium electrode potential of Cu is much lower than that of Au, Pt, and Pd [38][39][40], which offers a great driving force for the selective dissolution of Cu under free-dealloying conditions. After dealloying for 24 h, the ratio of remaining Cu and the other three elements is nearly equal, and the calculated physical parameters in Table 1 satisfy the empirical rules for forming HEAs.…”