Hollow Bowl NiS2 @polyaniline Conductive Linker/Graphene Conductive Network: A Triple Composite for High-Performance Supercapacitor Applications.

The achievement of the outstanding theoretical capacitance of nickel sulfide (NiS2 ) is challenging due to its low conductivity, slow electrochemical kinetics, and poor structural stability. In this study, we utilize polyaniline (PANI) as a linker to anchor the NiS2 with a hollow bowl-like structure, uniformly dispersed at the surface of graphene oxide (GO)(NiS2 @15PG). The presence of PANI provides growth sites, resulting in a uniform and dense arrangement of NiS2 . This morphological modulation of NiS2 increases the contact area between the active material to electrolyte. Additionally, PANI effectively connects NiS2 with the conductive network of GO, which advances the electrical conductivity and ion diffusion properties. As a result, the Rct (charge transfer resistance) and Zw (Warburg impedance) of NiS2 @15PG decrease by 82.61 % and 66.76 % respectively. This unique structure confers NiS2 @15PG with high specific capacitance (536.13 C g-1 at 1 A g-1 ) and excellent multiplicative property of 60.93 % at 20 A g-1 . The assembled NiS2 @15PG//YP-50 supercapacitors (HSC) demonstrates an energy density (13.09 Wh kg-1 ) at a high-power density (16 kW kg-1 ). The capacity retention after 10,000 cycles at 5 A g-1 is 86.59 %, indicating its significant potential for practical applications.

2D/2D MgO/g-C3N4 S-scheme heterogeneous tight with Mg-N bonds for efficient photo-Fenton degradation: Enhancing both oxygen vacancy and charge migration.

Construction of S-scheme heterojunction is an efficient strategy to enhance photocatalytic efficiency. Besides the retained redox ability, the wide work function gap and intimate interface contact are essential for efficient degradation. Nontoxic magnesium oxide (MgO) with two dimensional (2D) structures and high work function is a potential material for S-scheme photocatalysts. Herein, MgO was used to in-situ grown on graphitic carbon nitride (g-C3N4) for constructing the strongly connected MgO/g-C3N4 S-scheme photocatalyst with tight Mg-N bonds. Meanwhile, the presence of Mg-N bonds induces the formation of oxygen vacancy in MgO, which enhances the Fenton-like degradation. Furthermore, the Mg-N bond promotes the charge migration between MgO and g-C3N4. Consisting of the enhanced Fenton-like process and photocatalysis, the MgO/g-C3N4 shows a higher photo-Fenton degradation activity (80.01%) for degradation of organic pollutants (Rhodamine B, 100 mg L-1) in water, than g-C3N4 (28.46%) and MgO (55.64%). Therefore, the interfacial chemical bonds in heterojunction photocatalysts provide an efficient strategy for further enhancing the photocatalysis of S-scheme photocatalysts.