Layer-structured MoS₂ is regarded as a promising anode material for potassium ion batteries. Herein, MoS₂ nanosheets on N, P-codoping reduced graphene oxide (MoS₂/N, P-rGO) have been successfully prepared via a facile two-step synthesis, where few-layered MoS₂ nanosheets are chemically bonded onto the surface of N, P-rGO. As an anode material, MoS₂/N, P-rGO exhibits a high specific capacity (462.7 mAh·g⁻¹ at 100 mA·g⁻¹ over 200 cycles), outstanding rate capability (224.9 mAh·g⁻¹ at 20 A·g⁻¹), and excellent cycle life (236.6 mAh·g⁻¹ at 2 A·g⁻¹ after 7,000 cycles), much better than those of MoS₂ and MoS₂/rGO. These advanced performances outperform most of the reported anode materials for potassium ion batteries to date. Meanwhile, the K-storage reactions of MoS₂/N, P-rGO have been disclosed through in-situ and ex-situ characterizations. The kinetics analysis confirms that K-storage of MoS₂/N, P-rGO is predominant by pseudo-capacitance.

A bio-nanocluster (Fe₃O₄@bacteria) was prepared by simply mixture using the bacterial suspension and Fe₃O₄ nanoclusters to remove Congo red (CR) contamination from water resources. The bio-nanocluster was characterized by SEM, TEM and XPS. Adsorption efficiency, adsorption process and adsorption mechanism were comprehensively investigated. The maximum adsorption capacity (Q_m) of CR dye onto the Fe₃O₄@bacteria peaked at 320.1 mg/g, which was 2.88 times that of Fe₃O₄ under the same condition. Based on the equilibrium and kinetic studies, the Langmuir isotherm theory and pseudo-first-order model is appropriate to describe the adsorption process. The adsorption of CR is spontaneous and exothermic according to the thermodynamics parameters (ΔG^θ, ΔH^θ and ΔS^θ). The adsorption force dominated the Van der Waals force, biofloculation and chemisorption. The Fe₃O₄@bacteria could be applied potentially as an absorbent with high efficiency and environmentally friendly remediation of dyeing wastewater.