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The combination of electrochemistry and mass spectrometry is a powerful analytical tool for studying redox reaction mechanisms and identifying products or intermediates. However, the previously reported devices all require bespoke fabrication and are too complicated to be assembled and used by others. Crucially, the long ion transport distance and small spray volumes make it difficult to capture the short-lived intermediates. We present a practical mass spectrometric method in which surface-modified carbon fiber paper is innovatively applied to detect electrogenerated intermediates. Treating carbon fiber paper with dilute nitric acid removes its surface impurities, enhancing the capability of electro-redox. Electrospray ionization and redox reaction occur simultaneously on the tip of the paper. Transient electro-redox species generate and transfer into gas phase as soon as the appearance of spray. Rapid transport of quantities of electrogenerated ions to the mass spectrometer inlet makes it possible for mass spectrometric identification on the millisecond scale. The short-lived radical cations and iminium ions were successfully captured, reflecting the starting step of the cross-dehydrogenation coupling reaction. The real-time oxidation and online functionalization reactions of tertiary amines were achieved using this device without additional oxidants and electrolytes. In this way we could achieve in-depth mechanistic understanding and rapid screening of serial reactions. [Display omitted] • Treating carbon fiber paper with dilute nitric acid enhances the capability of detecting electrogenerated intermediates. • A-CFPSI permits the real-time monitoring of electrochemical reaction intermediates on the millisecond scale. • No additional electrolytes and oxidants are required, avoiding interference with the mass spectrum. • A-CFPRSI can be used for rapid screening of electrochemical reactions and mechanism researches. [ABSTRACT FROM AUTHOR]

[Display omitted] • Free-standing composite papers of SFCP@PANI were prepared. • The free-standing SFCP@PANI-2 paper was directly utilized as supercapacitive electrodes. • The SFCP@PANI-2 demonstrated an enhanced electrochemcial capacitive performance. Free-standing composite papers of SFCP@PANI were prepared by in situ polymerization of aniline on the surface of sisal fiber carbon paper (SFCP). The SFCP@PANI papers can be directly built into electrodes without the need for any binders or conductive agents. SFCP@PANI-2 exhibits excellent electrochemical performance in the three-electrode system and the coin-type symmetric supercapacitor (SSC), which indicates that it may be a promising electrode material for supercapacitor. [ABSTRACT FROM AUTHOR]

[Display omitted] • It is easier and cheaper to produce sisal fiber carbon paper supercapacitor electrodes in various shapes. • The free-standing SFCPs were directly utilized as supercapacitive electrodes. • SFCP-900 exhibited relatively good electrochemical properties in supercapacitor. Sisal Fiber Carbon Papers (SFCPs) with high specific surface area was obtained using a simple hydrothermal, pressing and carbonization method. The effects of calcination temperature on morphology, structure, pore structure and electrochemical properties of SFCPs were systematically studied. The free-standing SFCPs were directly utilized as supercapacitive electrodes, and the results revealed that the SFCPs calcinated at 900 °C (SFCP-900) exhibit a better specific capacity than SFCP-800 and SFCP-1000. These results suggested that the SFCP-900 has potential applications in supercapacitors. [ABSTRACT FROM AUTHOR]