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In this study, we demonstrate noble metal-free Fe–N-codoped graphene nanoshells (Fe–N/GNS) derived from petroleum pitch as highly efficient and cost-effective catalysts for nitroaromatics reduction. By employing α-Fe2O3nanoparticles simultaneously as both the hard template and the metal source, Fe–N/GNS can be facilely synthesized through the template-oriented method, followed by thermal annealing with urea for nitrogen doping. Owing to the high-dispersed synergetic Fe–N active sites as well as the hierarchical porous nanoshell structure, the Fe–N/GNS catalysts show remarkable catalytic performance and good tolerance for the reduction of nitroaromatics with NaBH4aqueous solution. The optimized Fe–N/GNS-800 corresponds to pseudo-first-order kinetics for p-nitrophenol reduction at room temperature, with the rate constant (k) reaching 1.23 min–1. The reinforced structure also allows the catalyst to be readily recycled a dozen times without activity deterioration. This work may provide a new avenue to facilely fabricate cost-effective but powerful catalysts for nitroaromatics reduction and beyond.

Effective regulation of the electronic structure of SrIrO3perovskite by trace Pt incorporation contributes to enhancements in activity and durability for acidic OER.

The design and fabrication of versatile covalent organic frameworks (COFs) with multiple properties for diverse applications is highly desirable. Here, the difunctional COFs material g–C18N3–COF was prepared and modified to be applied for efficient photocatalytic degradation of Rhodamine B (RhB) and pH detection, respectively. Owing to the triazine unit which was suitable for photocatalyst construction, g–C18N3–COF was sensitive to visible light and exhibited excellent photocatalysis capability toward RhB. Specially, the photocatalytic degradation of RhB with a high concentration of 300 ppm using g–C18N3–COF reached equilibrium within 6 h. Moreover, g–C18N3–COF was further grown in-situ onto the filter paper to generate a novel composite material g–C18N3–COF@Paper with bright yellow fluorescence. g–C18N3–COF@Paper could visualize the pH detection by remarkable changes in its fluorescent intensity and color in the range of pH value from 1 to 5, on account of the protonation of the nitrogen atoms from the triazine ring in g–C18N3–COF. The triazine-based sp2carbon-conjugated g–C18N3–COF, respectively, used as photocatalyst and sensor in this work offers a new strategy to construct the versatile COFs material, facilitating the application of functional COFs in the environmental protection field.

The search of functionalized covalent organic frameworks (COFs) materials is significant on account of their great promise for frontline applications in various fields. Herein, a novel and convenient tactic is developed to design and fabricate the tetrazole-functionalized COFs materials with abundant nitrogen atoms, which can provide active sites, facilitating the incorporation of COFs with metal ions. In particular, a β-ketoenamine-linked covalent organic frameworks named COF-TpDb is selected as precursor for post-synthetic modification to introduce the tetrazole moieties to coordinate with metal ions cobalt (Co2+) and palladium (Pd2+), giving two functional metal-coordinated COFs complexes COF-TpDb-TZ-Co and COF-TpDb-TZ-Pd. The resultant COF-TpDb-TZ-Co displays a higher oxygen evolution reaction activity with a lower overpotential of 390 mV at current density of 10 mA cm-2, which is much enhanced compared to COF-TpDb-TZ. The tactic for the fabrication of tetrazole-functionalized COFs with abundant nitrogen atoms implements rational design for the construction of functional COFs and expands the promising application of metal-coordinated COFs materials in electrocatalysis.