Yidong Zhang,Jianfei Ding,Wei Xu,Min Wang,Rong Shao,Ying Sun,Baoping Lin
Sol-gel strategies have attracted enormous attention in synthesis of perovskite-type oxides due to their excellent chemical homogeneity and possibility in controlling the size, morphology, chemical properties and texture of particles. Nevertheless, their complicated, time-consuming process and weak control over porous structure impeded their potential use in preparation of energy storage materials. Herein, a simple and rapid strategy based on MOF gel (MIL-100-Fe) is developed for fabricating mesoporous perovskite-type materials. The MOF gel can be synthesized in controllable time duration without multi complexing agent, particular pH conditions and high temperature treatment. The synthesized perovskite LaFeO 3 has mesoporous structure and the pore size is concentrated at 2 nm, which contribute to a specific capacitance of 241.3 F g −1 at 1 A g −1 with retention of 68% even at a high current density of 20 A g −1 . Meanwhile, the all-solid-state symmetric supercapacitor shows a wide potential window of 1.8 V, and an outstanding energy density of 34 W h kg −1 at a power density of 900 W kg −1 with 92.2% capacitance retention after 5000 cycles, outperforming previously reported perovskite-type electrode materials and even comparable to MOF derived iron oxides. Thus, this study opens a new way to construct porous perovskite-type electrode materials for supercapacitors, which can combine the chemical homogeneity of sol-gel technology and the porous properties of MOF template together.
Membrane-based gas separation offers notable energy efficiency benefits for hydrogen purification, yet it is often hindered by the inherent trade-off between permeability and selectivity. To address this challenge, a novel mixed matrix membrane (MMM) design is presented to boost H 2 separation performance via continuous hydrogen spillover mechanisms for the first time. The MMM incorporates a palladium-functionalized ZIF-67 gel (Pd@ZIF-67 gel) network into a polymer of intrinsic microporosity (PIM-1) matrix. The ZIF-67 gel network serves as a uniform dispersion medium for palladium nanoparticles (Pd NPs), thereby generating a multitude of active sites. These exposed sites, in conjunction with the microporous structure of ZIF-67, facilitate hydrogen dissociation and establish a continuous hydrogen spillover pathway throughout the membrane. This synergistic MMM design leads to substantial improvements in both hydrogen transport and selectivity. At an optimal loading of 28 wt% Pd@ZIF-67 gel, the MMMs exhibit a H 2 permeability of 3620 Barrer and a remarkable 417% enhancement in H 2 /CH 4 selectivity (24.9), surpassing the 2008 upper bound. This approach paves the way for the development of advanced materials tailored for gas separation applications.
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