Inhibited Surface Diffusion of High-Entropy Nano-Alloys for the Preparation of 3D Nanoporous Graphene with High Amounts of Single Atom Dopants
Xiaorong Lin, Yixuan Hu, Kailong Hu, Xi Lin, Guoqiang Xie, Xingjun Liu, Kolan Madhav Reddy, Hua‐Jun Qiu
Abstract
Nitrogen- and metal-atom-doped graphene are very promising electrocatalysts for many renewable energy conversion reactions such as oxygen reduction/evolution reactions (ORR/OER). To maximize the bifunctional or multifunctional catalytic performance, increasing the doping amount of both nonmetal nitrogen and metals on large-surface-area free-standing 3D porous graphene is very desirable. Herein, we design and prepare 3D bicontinuous nitrogen and noble-metal single atoms/clusters-doped small-pore-size nanoporous graphene by a CVD process using a designed 12-component ultrahigh-entropy nanoporous alloy template, which has greatly inhibited surface diffusion even under high temperatures of 800–1000 °C because of the incorporation of a suitable amount of high-melting-point metals. With a small-pore size of ∼16.7 nm and a high curvature, the 3D nanoporous graphene is able to host/stabilize a high amount of N (5.88 at. %) and metal single atoms/clusters (Au, Pt, and Ir), which are in situ anchored on graphene during the removal of the nanoporous template. As a result, the obtained 3D graphene-based composite exhibits excellent electrocatalytic activities toward both ORR and OER in both alkaline and acidic media. This work demonstrates a scalable and economic route to prepare metal- and nonmetal-codoped 3D graphene with ultrasmall porosity for different electrochemical applications.