Multifunctional FeS2 in binder-independent configuration as high-performance supercapacitor electrode and non-enzymatic H2O2 detector

Multifunctional FeS2 electrode that holds great promise for energy storage and biological application is developed in the present study in a binder-less configuration. X-ray diffractometry, Raman and X-ray photoelectron spectroscopy, high-resolution transmission and scanning electron microscopy reveals that such electrode design is characterized by a dense and well-ordered array made of highly crystalline FeS2 nanotubes directly built on a variety of conducive substrates. The characteristic solid contact and the open framework in such binder-free scheme synergistically well strengthen the functionality of FeS2 as on the one hand a highly appealing supercapacitor electrode to deliver an outstanding specific capacitance amounted to 320 F/g along with an excellent energy density of 78.7 Wh/kg and a power delivery of 8.81 kW/kg, respectively, upon coupled with MnO2 to build an asymmetric supercapacitor. Moreover, the FeS2 electrode on the other hand as an enzyme-free biosensor is also highly competitive in view of the high selectivity and the superior sensitivity of 612 mu A/mM cm(2) to electrochemically detect ultradiluted H2O2 at a concentration of only 0.25 mu M.