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Cyclic voltammetry and positronium (Ps) 3 γ -annihilation spectroscopy were applied to investigate pore interconnectivity/morphology of porous silica films fabricated with various loading of cetyltrimethyl ammonium bromide (CTAB). With increasing the ratio of CTAB up to 15 wt.%, the total charge Q , resulted from I − diffusion across the silica films, increased remarkably, indicative of formation of highly interconnected pores in the films prepared with more porogen. However, it decreased dramatically with further loading CTAB of 25 wt.%. Interestingly, 3 γ -annihilation fraction I 3 γ due to a triplet-state Ps ( ortho -positronium, o -Ps) emission from the silica films showed a similar behavior as a function of CTAB loading. The abnormal decrement in Q and I 3 γ in the film fabricated with 25 wt.% CTAB was well explained by formation of long nanochannels aligning parallel to the film surface. The results indicated that the total charge Q and Ps 3 γ -annihilation fraction were closely associated with I − and Ps diffusion governed by the pore interconnectivity/morphology of the silica films, which made cyclic voltammetry possible to be a feasible tool to characterize pore interconnectivity/morphology of porous thin films. [ABSTRACT FROM AUTHOR]

Highlights: [•] Decrements in S value and water uptake coefficient confirm the post-cure process. [•] Molecular chain scission leads to the formation of microporous structure. [•] The formation of an aged layer with high density is verified by EIS. [Copyright &y& Elsevier]

• MOFs are promising precursors to prepare heteroatom-doped porous carbon for high-performance supercapacitor. • CMC was used as continuous carbon agent to connect MOFs-derived carbon for the NGCA network. • K 2 FeO 4 was used as both activation agent and catalyst to prepare graphitic carbon. Metal–organic frameworks (MOFs) are promising precursors to prepare heteroatom-doped porous carbon for high-performance supercapacitor. N-self-doped graphitic carbon aerogels (NGCA) with hierarchically porous tunnels, high graphitization degree, high N content and 3D conductive network structure are successfully prepared by dry-freezing and successive high temperature treatment of ZIF-8/carboxymethylcellulose (CMC)/potassium ferrate (K 2 FeO 4) composites, using CMC as continuous carbon agent for MOFs-derived carbon and K 2 FeO 4 as both activation agent and catalyst. When applied in a supercapacitor, the obtained NGCA exhibit excellent capacitive performance and remarkable energy-power characteristics. The specific capacitance of NGCA electrode is 244 F/g at 1 A/g in three-electrode system. NGCA based symmetric supercapacitor shows a high energy density of 17.08 Wh/kg at a power density of 500 W/kg. These results confirm NGCA as electrode material can be applied for high-performance supercapacitor. [Display omitted] [ABSTRACT FROM AUTHOR]