Herein, the synergistic effects of hollow nanoarchitecture and high specific surface area of hollow activated carbons (HACs) are reported with the superior supercapacitor (SC) and capacitive deionization (CDI) performance. The center of zeolite imidazolate framework-8 (ZIF-8) is selectively etched to create a hollow cavity as a macropore, and the resulting hollow ZIF-8 (HZIF-8) is carbonized to obtain hollow carbon (HC). The distribution of nanopores is, subsequently, optimized by KOH activation to create more nanopores and significantly increase specific surface area. Indeed, as-prepared hollow activated carbons (HACs) show significant improvement not only in the maximum specific capacitance and desalination capacity but also capacitance retention and mean desalination rates in SC and CDI, respectively. As a result, it is confirmed that well-designed nanoarchitecture and porosity are required to allow efficient diffusion and maximum electrosorption of electrolyte ions.

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In this study, we successfully demonstrate the synthesis of a novel necklace-like Co, Fe, and N co-doped one-dimensional (1D)-assembly of hollow carbon nanoboxes (1D-HCNB-x) and its potential for supercapacitor application.

Hollow carbon‐based nanoarchitectures (HCAs) derived from zeolitic imidazolate frameworks (ZIFs), by virtue of their controllable morphology and dimension, high specific surface area and nitrogen content, richness of metal/metal compounds active sites, and hierarchical pore structure and easy exposure of active sites, have attracted great interests in many fields of applications, especially in heterogeneous catalysis, and electrochemical energy storage and conversion. Despite various approaches that have been developed to prepare ZIF‐derived HCAs, the hollowing mechanism has not been clearly disclosed. Herein, a specialized overview of the recent progress of ZIF‐derived HCAs is introduced to provide an insight into their preparation strategy and the corresponding hollowing mechanisms. Based on the fundamental understanding of the structural evolution of ZIF nanocrystals during the high‐temperature pyrolysis process, the hollowing mechanisms of ZIF‐derived HCAs are classified into four categories: i) inward contraction of core–shell template@ZIF composites or hollow ZIFs, ii) outward contraction of ZIF@shell composites, iii) special outward contraction of ZIF arrays, and iv) mechanism beyond inward/outward contraction of pure ZIF nanocrystals. Finally, an outlook on the development prospects and challenges of HCAs based on ZIF precursors, especially in terms of controlled synthesis and future electrochemical application, is further discussed.

Correction for ‘Co, Fe and N co-doped 1D assembly of hollow carbon nanoboxes for high-performance supercapacitors’ by Minjun Kim et al., J. Mater. Chem. A, 2022, 10, 24056–24063, https://doi.org/10.1039/D2TA06950D.

This work reports the fabrication of mesoporous Al2O3-TiO2 composites with various contents of TiO2 and their utilization as adsorbents for molybdenum anions with potential application in medical radioisotope production. The increase of TiO2 promotes the deposition of more TiO2 nanoparticles on the surface of the Al2O3 support without altering the original morphology. Furthermore, alumina samples loaded with smaller amounts of TiO2 (Al2O3-2.5% Ti (20.01 mass% TiO2) and Al2O3-5% Ti (34.55 mass% TiO2)) are amorphous in nature. However, at a high loading (Al2O3-10% Ti (63.97 mass% TiO2)), anatase TiO2 becomes the dominant phase, suggesting the extensive coverage of the Al2O3 surface by TiO2 NPs. The TiO2 modification is also observed to greatly increase the surface area from 177 m2 g−1 for pristine γ-Al2O3 to as high as 982 m2 g−1 for Al2O3-5% Ti sample. When employed for molybdenum adsorption, the Al2O3-5% Ti sample displays a higher Mo adsorption capacity (44.5 mg g−1) than Al2O3-2.5%Ti (39.0 mg g−1), Al2O3-10%Ti, (40.5 mg g−1), and pristine γ-Al2O3 (37.1 mg g−1) samples. The larger surface area and presence of additional hydroxyl groups for attracting the molybdenum anions contribute to the enhanced adsorption capacities of the Al2O3-TiO2 composites compared to that of pristine γ-Al2O3.

This work demonstrates the fabrication of a nanoporous iron carbide-iron oxide/reduced graphene oxide (IC-IO/ rGO) hybrid via a controlled one-step thermal treatment of Prussian blue (PB)/GO hybrid at 450 °C under N 2 flow. The PB/GO hybrid is initially prepared through the in-situ deposition of PB nanoparticles on the GO sheets through electrostatic interactions. The morphological analysis of the hybrid reveals the uniform coverage of the rGO sheets by IC-IO nanoparticles and the even distribution of carbon (C), oxygen (O), and iron (Fe) on the rGO nanosheets. As a result of the hybrid composition and controlled morphology, the surface area of the obtained IC-IO/rGO hybrid (~40 m 2 /g) is significantly enhanced compared to those of the calcined GO sheets and PB nanoparticles (without GO).