Jing Liua, Boyang Zhanga, Yumeng Fob, Jie Gaoa, Wanqing Yua, Huanwei Rena,
Xuejing Cuia, Xin Zhou,b,* Luhua Jiang a,*
a Electrocatalysis & Nanomaterial Laboratory, College of Materials Science & Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China.
b College of Environment and Chemical Engineering, Dalian University, Dalian, 116622, China.
Abstract:
Developing highly efficient and CO-tolerant hydrogen oxidation electrocatalysts is crucial for anion exchange membrane fuel cells (AEMFC). In this work, a unique carbon molecular sieve (CMS) coating strategy is demonstrated for Ru nanoclusters, featuring strongly size sieving ultramicropores, which acts as a highly efficient and CO tolerant hydrogen electrocatalyst in alkaline conditions. The CMS coating thickness and pore size could be regulated by low-temperature carbonization of polydopamine which was beforehand in-situ polymerized over the Ru nanoclusters. It is demonstrated that dominant sub-4Å ultramicropores in Ru@NC/C-400 are beneficial for H2/CO separation. Taking advantage of such a physical sieving barrier, along with the electronic modulation of Ru by the carbon coating layer, the CO adsorption over Ru surface is suppressed and meanwhile the hydrogen/oxygen species adsorption energy are optimized. The Ru@NC/C-400 catalyst exhibits exceptional HOR activity with a specific activity of 0.30 mA cm-2Ru and a mass activity of 0.25 A mg-1 Ru, which are 3-folds and 1.7-folds of the counterpart Pt/C catalyst, respectively. More importantly, the catalyst is highly tolerant to CO. In the presence of 100 ppm CO, the HOR current with the Ru@NC/C-400 catalyst lowers by just 9.5%, but the Pt/C catalyst drops by 33.3% in the chronoamperometry test. This work highlights the tremendous potential of the encapsulating approach in refreshing catalyst performances via rationally engineering the encapsulating layer structures.
Keywords: Hydrogen electrocatalysis; alkaline media; Ru nanoparticles; encapsulating; CO-tolerant
*Corresponding authors
E-mail address: zhouxin@dlu.edu.cn; luhuajiang@qust.edu.cn.
https://doi.org/10.1016/j.cej.2023.143438
