In this work, we employ simple hydrothermal method to synthesize metal-organic framework (MOF)-derived selenide from reduced graphene oxide (rGO) / structured zeolitic imidazolate framework (ZIF). The resulting MOF-derived selenide ((rGO/ZIF)@Se)...

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Vanadium dioxide (VO2) has been a promising energy-saving material due to its reversible metal-insulator transition (MIT) performance. However, the application of VO2 films has been seriously restricted due to the intrinsic low solar-energy modulation ability (ΔTsol) and low luminous transmittance (Tlum) of VO2. In order to solve the problems, the surface structure of VO2 particles was regulated by the quenching process and the VO2 dispersed films were fabricated by spin coating. Characterizations showed that the VO2 particles quenched in deionized water or ethanolreserved VO2(M) phase structure and they were accompanied by surface lattice distortion compared to the pristine VO2. Such distortion structure contributed to less aggregation and highly individual dispersion of the quenched particles in nanocomposite films. The corresponding film of VO2 quenched in water exhibited much higher ΔTsol with an increment of 42.5% from 8.8% of the original VO2 film, because of the significant localized surface plasmon resonance (LSPR) effect. The film fabricated from the VO2 quenched in ethanol presented enhanced thermochromic properties with 15.2% of ΔTsol and 62.5% of Tlum. It was found that the excellent Tlum resulted from the highly uniform dispersion state of the quenched VO2 nanoparticles. In summary, the study provided a facile way to fabricate well-dispersed VO2 nanocomposite films and to facilitate the industrialization development of VO2 thermochromic films in the smart window field.

For large-scale applications, dye-sensitized solar cells (DSSCs) require the replacement of the scarce platinum (Pt)-based counter electrode (CE) with efficient and cheap alternatives. In this respect, low-cost perovskite oxides (ABO3) have been introduced as promising additives to composite-based CEs in Pt-free DSSCs. Herein, we synthesized composites from La0.9Ce0.1NiO3 (L) perovskite oxide and functionalized-multiwall-carbon-nanotubes wrapped in selenides derived from metal-organic-frameworks (f-MWCNT-ZnSe-CoSe2, “F”). L and F were then mixed with carbon black (CB) in different mass ratios to prepare L@CB, F@CB, and L@F@CB composites. The electrochemical analysis revealed that the L@F@CB composite with a mass ratio of 1.5:3:1.5 exhibits better electrocatalytic activity than Pt. In addition, the related DSSC reached a better PCE of 7.49% compared to its Pt-based counterpart (7.09%). This improved performance is the result of the increase in the oxygen vacancy by L due to the replacement of La with Ce in its structure, leading to more active sites in the L@F@CB composites. Moreover, the F@CB composite favors the contribution to the high electrical conductivity of the hybrid carbon nanotube–carbon black, which also offers good stability to the L@F@CB CE by not showing any obvious change in morphology and peak-to-peak separation even after 100 cyclic voltammetry cycles. Consequently, the corresponding L@F@CB-based device achieved enhanced stability. Our work demonstrates that L@F@CB composites with a low cost are excellent alternatives to Pt CE in DSSCs.