The BP@Ni ₃ Se ₄ /CoSe ₂ heterostructure delivers superior sodium storage performance with long cycling stability and high energy density.

An efficient and eco-friendly procedure for the synthesis of 1-amidoalkyl-2-naphthol and tetrahydrobenzo[b]pyran derivatives has been developed through a one-pot three-component condensation of aldehydes with 2-naphthol and amides, or with malononitrile and dimedone in the presence of magnetic nanoparticle supported acidic ionic liquid (AIL@MNP) as a novel heterogeneous catalyst under solvent-free conditions. This new procedure offers several advantages such as short reaction time, excellent yields, operational simplicity and without any tedious work-up for catalyst recovery or product purification. Moreover, the catalyst could be simply separated by an external magnet and reused six times without significant loss of catalytic activity.

Due to their high specific capacity, straightforward manufacture, and plentiful sources, transition metal oxides and dichalcogenides are regarded as the perfect anode materials for sodium ion batteries (SIBs). Among them, MoSe₂ could be used as an SIB anode material due to its evident structural and performance benefits, including its two-dimensional layered structure with a large layer spacing (0.646 nm), a theoretical capacity of up to 422 mA h g⁻¹, low cost, and environmental friendliness. However, the low conductivity of MoSe₂ can easily lead to large impedance, resulting in poor rate performance. And the huge volume expansion in the process of sodium storage will result in the collapse and crushing of the MoSe₂ structure. In this work, a Co doped MoSe₂@carbon nanosheet (Co-MoSe₂@CN) is fabricated by a facile liquid phase method with a subsequent pyrolytic selenization technique. Through this electronic modulation process, the energy band gap of MoSe₂ is directly reduced from 1.365 eV to 0.195 eV, and the conductivity is significantly enhanced. Additionally, the volume tension brought on by sodium ion (de)insertion can be released and absorbed by the Co-MoSe₂@CN structure. As an anode for SIBs, Co-MoSe₂@CN exhibits outstanding performance in terms of a high specific capacity of 403 mA h g⁻¹ at 1 A g⁻¹ (300 cycles) and extended length cycling stability (373 mA h g⁻¹ at 10 A g⁻¹ after 1000 cycles), as well as the rate capability, which is better than that of MoSe₂@CN in all aspects of rolling. Furthermore, the Co-MoSe₂@CN anode helps sodium-ion full batteries attain a high energy density of 103 W h kg⁻¹ (210 W kg⁻¹). The high pseudo-capacitance and diffusion control play a leading role in the sodium storage of Co-MoSe₂@CN. This electronic structure manipulation of MoSe₂ and adsorption of Na ions are confirmed by theoretical calculation. This offers a viable design for the advancement of SIB anodes based on transition metal selenides.

An interfacial covalent bonding strategy is proposed to synthesize the MXene-stabilized Sb₂Se₃nanotube hybrid.