“…To further measure the functional groups of a series of FeS 2 @MoO 2 (Fe–Mo-1, Fe–Mo-2, and Fe–Mo-3), their FT-IR spectra were recorded and are depicted in Figure d. The peaks at 1090, 595, and 934 cm –1 were derived from Fe–S, S–S, and Mxe5fbO, respectively, demonstrating the successful formation of FeS 2 @MoO 2 composites. , Likewise, the peak located at 559 cm –1 came from the vibration of Fe–O–Mo, mainly ascribed to the formed Fe–O–Mo interfacial bonds. − In the spectra of Fe–Mo-2 and Fe–Mo-3, the peak at 466 cm –1 could be found, which was related to the vibration of Mo–S, perhaps derived from the formation of MoS 2 . , Compared to the functional groups of Fe–Mo-1, abundant groups could be noted in Fe–Mo-2 and Fe–Mo-3, which could offer more electron pairs, further providing abundant active and adsorption sites for polysulfides, accompanied with the fast adsorption/desorption of electrons. Further exploring the interfacial bonds of FeS 2 @MoO 2 , the obvious signals at g = 2.003 could be observed by the ESR spectrum in Figure e, verifying the existence of sulfur vacancies.…”