Superior energy storage properties in SrTiO3-based dielectric ceramics through all-scale hierarchical architecture.

The restricted energy density in dielectric ceramic capacitors is challenging for their integration with advanced electronic systems. Numerous strategies have been proposed to boost the energy density at different scales or combine those multiscale effects. Herein, guided by all-scale synergistic design, we fabricated Sr0.7Bi0.2TiO3 ceramics doped with (Bi0.5Na0.5)(Zr0.5Ti0.5)O3 by sintering the nanopowders by solution combustion synthesis, which demonstrate exceptional energy storage performance (ESP). Notably, an ultrahigh recoverable energy density of 11.33 J cm-3, accompanied by an impressive energy efficiency of 89.30%, was achieved at an extremely high critical electric field of 961 kV cm-1. These primary energy storage parameters outperform those of previously reported ceramic capacitors based on SrTiO3. Additionally, an excellent comprehensive performance is also realized, including a substantial power density of 156.21 MW cm-3 (at 300 kV cm-1), an extraordinarily short discharge time of 97 ns, a high Vickers hardness rating of approximately 8.23 GPa, and outstanding thermal and frequency stability. This enhancement can be attributed to the synergistic effect at all scales from atomic substitution, polar nano regions, submicrometer grain, and sample thickness. Consequently, this panoscopic approach has effectively demonstrated the potential to enhance the ESP of dielectric ceramics.

Direct Synthesis of Magnetic CoFe2O4 Nanoparticles as Recyclable Photo-Fenton Catalysts for Removing Organic Dyes.

Herein, CoFe2O4 nanoparticles were directly synthesized through a solution combustion method using ferric nitrate, cobalt nitrate, and glycine as raw materials. The effects of glycine on the phase composition and magnetic properties of the CoFe2O4 products were investigated. When the fuel/ferric nitrate ratio was 0.8, the obtained product was pure CoFe2O4 with an average particle size of 25 nm. Furthermore, the saturation magnetization is 77.3 emu/g, which is about 95.7% that of CoFe2O4 bulk materials at room temperature and good for recycling. The photo-Fenton catalytic properties of CoFe2O4 were investigated for assessing its efficacy in removing dyes. It could degrade the 20 ppm MB in 75 min. To improve the photo-Fenton catalytic performance, NH4HCO3 and glucose were employed as additives. Due to the pores formed by NH4HCO3 and glucose, the G-CoFe2O4 and N-CoFe2O4 could degrade the 20 ppm MB in 40 and 25 min, respectively. The results indicated that these additives can effectively improve the catalytic activity of CoFe2O4. The modified CoFe2O4 is a promising alternative recyclable photo-Fenton catalyst for removing organic dyes.

Facile route for synthesis of mesoporous graphite encapsulated iron carbide/iron nanosheet composites and their electrocatalytic activity.

Mesoporous graphite encapsulated Fe3C/Fe nanosheet composites have been synthesized by a facile template free method using ferric nitrate, glycine and glucose as raw materials. X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectrometer have been used to characterize the composites. The formation process and morphology of the products have been discussed in detail. Interestingly, this facile route can synthesize graphite encapsulated Fe3C, Fe3C/Fe and Fe composites with two dimensional nanosheet structure by tuning the reaction temperature and the Fe3C and Fe nanoparticles with size less than 30nm are well dispersed on the carbon sheet. The mesoporous graphite encapsulated Fe3C/Fe nanosheet composites with a high specific surface area have application in non-noble metal electrocatalysis for hydrogen evolution reaction.