Self-optimizing iron phosphorus oxide for stable hydrogen evolution at high current

• Published in: Applied catalysis. B, Environmental Environmental, 2021-12, Vol.298, p.120559, Article 120559
• Main Authors: Cao, Dengfeng, Sheng, Beibei, Qi, Zhenghang, Xu, Wenjie, Chen, Shuangming, Moses, Oyawale Adetunji, Long, Ran, Xiong, Yujie, Wu, Xiaojun, Song, Li
• Format: Article
• Language: English
• Subjects: Catalysts; Current density; Electrocatalysts; Electrochemistry; Electrolysis; Electrolytes; Ferric oxide; Fine structure; Fourier transforms; High current; Hydrogen; Hydrogen evolution; Hydrogen production; Optimization; pH effects; Phosphating (coating); Phosphorus; Phosphorus oxides; Single wall carbon nanotubes; Stability; Structural self-optimization; Synchrotron radiation; Synchrotrons; Ultrastructure; Water splitting; X ray absorption
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2021.120559

[Display omitted] •Using residual Fe species in the raw SWCNT as rivet sites to construct catalyst.•Structural self-optimization engineering derived three high-efficiency catalysts.•The obtained catalysts enables long-life catalysis at high current density.•Theoretical/experimental results confirmed that P atoms accelerated the catalysis. Electrocatalytic water splitting have demonstrated an established methodology to generate hydrogen of high purity, attracting lots of attention from industry. However, deficient supplies or poor electrochemical stability of catalysts contributes to unsatisfactory electrocatalytic hydrogen production, particularly while maintaining high current densities. Herein, we develop a robust catalyst by directly phosphating raw single-walled carbon nanotube films which can be self-optimized into O-FePx-SWCNT, P-Fe2O3-SWCNT or P-FeOOH-SWCNT catalysts, depending on the selected electrolytes with different pH values. The electrochemical measurements reveal the excellent electrocatalytic performance of catalytic films in a wide pH range. Notably, there is no observable degradation, even following one-week of continuous electrolysis process, which reached an elevated current density of 125 mA/cm2 at neutral conditions. In order to manifest its cogent applications, the catalyst is employed to stably electrolyze lake water, further indicating potential hydrogen production in inland areas. Our work confirms the feasibility of using structural self-optimization engineering to develop desirable electrocatalysts, providing flexible catalytic films for practical applications and answering the long-standing controversial question about active sites based on X-ray absorption fine structure (XAFS), operando synchrotron radiation Fourier transform infrared (SR-FTIR) spectroscopy and theoretical calculations, which will significantly contribute to the advancement of HER-related basic and applied research.