Ultrafine PtCo alloy by pyrolysis etching-confined pyrolysis for enhanced hydrogen evolution

Yi Zhang; Jianhong Lan; Yike Xu; Yuanyuan Yan; Weifeng Liu; Xuguang Liu; Shaonan Gu; Jiadong Zhou; Meiling Wang

doi:10.1016/j.jcis.2024.01.124

Ultrafine PtCo alloy by pyrolysis etching-confined pyrolysis for enhanced hydrogen evolution

J Colloid Interface Sci. 2024 Apr 15:660:997-1009. doi: 10.1016/j.jcis.2024.01.124. Epub 2024 Jan 22.

Authors

Yi Zhang¹, Jianhong Lan¹, Yike Xu¹, Yuanyuan Yan¹, Weifeng Liu¹, Xuguang Liu², Shaonan Gu³, Jiadong Zhou⁴, Meiling Wang⁵

Affiliations

¹ College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
² College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China. Electronic address: liuxuguang@tyut.edu.cn.
³ Key Laboratory of Fine Chemicals in Universities of Shandong, Jinan Engineering Laboratory for Multi-scale Functional Materials, School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China. Electronic address: sngu@qlu.edu.cn.
⁴ Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, and School of Physics, Beijing Institute of Technology, Beijing 100081, China.
⁵ College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China; Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, China. Electronic address: wangmeiling@tyut.edu.cn.

PMID: 38290326
DOI: 10.1016/j.jcis.2024.01.124

Abstract

Zeolitic imidazolate framework-67 (ZIF-67) has been widely used as a precursor to developing efficient PtCo alloy catalysts for hydrogen evolution reaction (HER). However, traditional in-situ pyrolysis strategies involve complicated interface structure modulating processes between ZIF-67 and Pt precursors, challenging large-scale synthesis. Herein, a "pyrolysis etching-confined pyrolysis" approach is developed to design confined PtCo alloy in porous frameworks of onion carbon derived from ZIF-67. The confined PtCo alloy with Pt content of only 5.39 wt% exhibits a distinct HER activity in both acid (η₁₀: 5 mV and Tafel: 9 mV dec^-1) and basic (η₁₀: 33 mV and Tafel: 51 mV dec^-1) media and a drastic enhancement in stability. Density functional theory calculations reveal that the strong electronic interaction between Pt and Co allows favorable electron redistribution, which affords a favorable hydrogen spillover on PtCo alloy compared with that of pristine Pt(111). Operational electrochemical impedance spectroscopy demonstrates that the Faraday reaction process is facilitated under acidic conditions, while the transfer of intermediates through the electric double-layer region under alkaline conditions is accelerated. This work not only offers a universal route for high-performance Pt-based alloy catalysts with metal-organic framework (MOF) precursors but also provides experimental evidence for the role of the electric double layer in electrocatalysis reactions.

Keywords: Electric double layer; Faraday process; HER; PtCo alloy; Pyrolysis etching-confined pyrolysis.