Enhanced catalytic activity and stability of CoAuPd nanocatalysts by combining methods of heat treatment and dealloying

摘要

Dealloying and heat treatment methods are combined to regulate the surface structure of CoAuPd nanocatalysts (NCs), and improve their activity and stability for methanol oxidation. The effect of the sequence of the two methods on the structure-activity-stability relationship is investigated and optimized. CoAuPd-1 and CoAuPd-3 NCs were prepared by simple co-reduction and successive reduction method, respectively. The CoAuPd NCs obtained by dealloying after heat treatment (CoAuPd-HD) have better dispersity, larger electrochemical active surface area (ECSA), higher activity, stability, and anti-CO poisoning durability. The mass and specific activity of CoAuPd-3-HD are 333.478 mA mg(Pd)(-1) and 1.109 mA cm(-2), respectively, which are higher than the CoAuPd-3 obtained by heat treatment after dealloying (CoAuPd-3-DH). The current densities of CoAuPd-3-DH and CoAuPd-3-HD remain 44.6 and 80.7% after 500 cycles, respectively, indicating that dealloying after heat treatment can significantly enhance the stability. The combination of heat treatment and dealloying is expected to provide a new idea for the design of low Pd, Pt-based catalysts with high activity and stability. (C) 2019 Elsevier Inc. All rights reserved.