Yiming Zhang,Xiaoyan Yang,Yonglin Wang,Peng Zhang,Dan Liu,Yongwei Li,Zhouzheng Jin,Bhekie B. Mamba,Alex T. Kuvarega,Jianzhou Gui
For obtaining ultra-fine Cu 2 S nanoparticles with reduced recombination of their photogenerated electron/hole pairs, in-situ growth of Cu 2 S nanoparticles on exfoliated MoS 2 nanosheets was achieved in this study. We have exhaustively studied l -cysteine in-situ conjugation with sulfur defects on the surface of MoS 2 nanosheets, which makes particle-level superlattice structured Cu 2 S nanoparticles (average 6.2 nm) well disperse on MoS 2 nanosheets. Further, XPS and Raman analysis confirm that the intense interfacial effects are formed between Cu 2 S and MoS 2 for the 2-Cu 2 S-MoS 2 composite, which significantly promote separation of photogenerated electron-hole pairs and prolong their lifetime, as shown by PL and TRPL. As a result, 2-Cu 2 S-MoS 2 exhibits the fastest photoreduction rate of Cr(VI) (0.0058 min −1 ) under visible light irradiations, which are almost 8.3 times and 2.9 times higher than that of MoS 2 nanosheets (0.0007 min −1 ) and pure Cu 2 S (0.002 min −1 ), respectively. Meanwhile, 2-Cu 2 S-MoS 2 also possesses an optimal composite proportion between Cu 2 S and MoS 2 , which presents outstanding photocatalytic activity among series of x-Cu 2 S-MoS 2 composites. The photoreduction mechanism of Cr(VI) is investigated in detail. As a matter of fact, l -cysteinecoupled with sulfur defects on MoS 2 nanosheets could produce the coordination inner heterojunction interface of 2-Cu 2 S-MoS 2 samples, which greatly improves migration efficiency of photoinduced carriers and ultimately endows it outstanding photoreduction activities. Furthermore, the strategy was extended to fabricate CdS-MoS 2 and ZnS-MoS 2 heterojunctions, implying that this strategy is of promising potentials for designing more active metal sulfides heterojunction photocatalysts.
Sodium-ion batteries (SIBs) are promising alternatives to lithium-ion batteries with similar working principles, cell structures, and material systems. However, attaining long-term stability and high-capacity performance of SIBs at ultrahigh rates remains a significant challenge due to the large ionic radius and slow kinetic behavior of Na + . Herein, a novel robust anode with a dual-biomimetic gradient hierarchical architecture is proposed and provide a simple strategy to fabricate this sulfur-doped mesoporous carbon concave hollow sphere/Ti 3 C 2 T x MXene (SCMX) anode. In addition, Cu 2 S nanoparticles are in situ embedded into the SCMX architecture by electrochemical induction during the cycling process to act as active sites, which enhances the rate performance and cycling stability. Relying on its hybrid architecture and in situ formed Cu 2 S, this SCMX anode can achieve high ion accessibility, rich active sites, rapid charge transfer, and favorable structure stability, as disclosed by in/ex situ characterizations. As a result, it exhibits high reversible capacity (745.6 mAh g −1 at 0.2 A g −1 ), ultrahigh-rate capability (380.5 mAh g −1 at 50.0 A g −1 ), and long cycling stability (98.2% capacity retention after 10 000 cycles at 80.0 A g −1 ). This work is anticipated to accelerate the development of high-performance SIBs and offer distinctive inspiration for the design of electrode structures/systems.
The interfacial microcracks in the resin matrix composites are difficult to be detected and repaired. However, the self-healing concept provides opportunities to fabricate composites with unusual properties. In the present study, photothermal conversion Ag–Cu2S nanoparticles were immobilized onto poly(p-phenylene benzobisoxazole) (PBO) fibers via a polydopamine chemistry. Benefitting from the photothermal effects of Ag–Cu2S, the obtained PBO fibers (Ag–Cu2S–PBO) efficiently converted the light energy into heat under Xenon lamp irradiation. Then, single PBO fiber composites were prepared using thermoplastic polyurethane as the matrix. It was found that the interfacial damage caused by single fiber pull-out was simply self-healed by Xe light irradiation. This wonderful interfacial damage self-healing property was mainly attributed to the in situ heating generation via photothermal effects of Ag–Cu2S in the composite interface. This paper reports a novel strategy to construct advanced composites with light-triggered self-healing properties, which will provide inspiration for preparing high performance composite materials.
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