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Morphology control and impurity doping are two widely applied strategies to improve the electrochemical performance of nanomaterials. Herein, we report an environmentally friendly approach to obtain Co-doped Ni(OH) 2 nanosheet networks using a laser-induced cobalt colloid as a doping precursor followed by an aging treatment in a hybrid medium of nickel ions. The shape and specific surface area of the doped Ni(OH) 2 can be successfully adjusted by changing the concentration of sodium thiosulfate. Furthermore, a Co-doped Ni(OH) 2 nanosheet network was further converted into Co-doped NiO with its pristine morphology retained via facile thermal decomposition in air. The structure and electrochemical performance of the as-prepared samples are investigated with scanning and transmission electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, Fourier transform infrared spectroscopy, the nitrogen adsorption-desorption isotherm technique, and electrochemical measurements. The Codoped Ni(OH) 2 electrode shows an ultrahigh specific capacitance of 1421 F g À1 at a current density of 6 A g À1 , and a good retention level of 76% after 1000 cycles, in sharp contrast with only a 47% retention level of the pure Ni(OH) 2 electrode at the same current density. In addition, the Co-doped NiO electrode exhibits a capacitance of 720 F g À1 at 6 A g À1 and 92% retention after 1000 cycles, which is also superior to the corresponding values of relevant pure NiO electrodes. The Co 2+ partially substitutes for Ni 2+ in the metal hydroxide and oxide, resulting in an increase of free holes in the valence band, and, therefore, enhancement of the p-type conductivity of Ni(OH) 2 and NiO. Moreover, such novel mesoporous nanosheet network structures are also able to enlarge the electrode-electrolyte contact area and shorten the path length for ion transport. The synergetic effect of these two results is responsible for the observed ultrahigh pseudocapacitor performance.

We report a facile approach to immobilize magnetic ZnFe 2 O 4 nanoparticles (NPs) onto reduced grapheme oxide (rGO) network by using highly reactive ZnO x (OH) y and FeO x colloids as precursors, which were respectively obtained by laser ablation of metallic zinc (Zn) and iron (Fe) target in pure water. Microstructure investigation of such nanocomposites (NCs) revealed that ZnFe 2 O 4 NPs are well-dispersed 10 onto rGO sheets. Such structure was helpful for separating the photoexcited electron-hole pairs and accelerating the electrons transfer. Electrochemical impedance measurements indicated the remarkably decrease of interfacial layer resistance of composite structure in compared to that of pure ZnFe 2 O 4 NPs. As a result of these advantages, such NCs present a prominent enhancement in photodegradation efficiency of methylene blue dye. Besides, the excellent magnetic properties of ZnFe 2 O 4 NPs allow the 15 catalysts being easily separated from the solution by a magnet for recycle utilization. This effort not only provided a new approach to fabricate ZnFe 2 O 4 -rGO NCs, also expanded the application of ZnFe 2 O 4 NPs used as a visible-light excited photocatalysts in application of organic pollutants degradation. 65 indicated that the MB has been degraded completely within 300 min. The degradation rates of the MB solution by using different photocatalysts were calculated as shown in Figure 4b. First, as a blank contrast, when the MB solution was only added with H 2 O 2 , the absorption peak at 664 nm is nearly unchanged after 70 irradiation for 300 min. Subsequently, when the pure ZnFe 2 O 4 A colloidal approach was developed to immobilize magnetic ZnFe 2 O 4 onto simultaneously reduced GO toward degradation of dyes under visible-light irradiation.

No abstract

Mg(OH)2 flakes composited on GO nanosheets as triggered by the colloidal electrostatic self-assembly in an liquid laser ablation process. The as-synthesized composite presented excellent adsorption performance for MB and heavy metal ions.

Sulfur/carbon composite were successfully fabricated by interfacial control strategy, superficial sulfur was effectively removed by optimizing the ratio and amount of mixed solvents, thereby operating well in carbonate-based electrolytes.

No abstract

Herein, we report a convenient route to fabricate pseudohexagonal phase niobium pentoxide (TT-Nb 2 O 5 ) nanopillars via combination of laser ablation in liquids (LAL) and hydrothermal treatment without using any organic surfactants or stabilizers. The morphology and structure of the assynthesized samples are investigated through scanning and transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Such nanopillars exhibit excel-lent lithium storage properties, including high reversible capacity, good rate capability, and excellent cycle stability (81% capacity retention after 1000 cycles) at a rate of 5 C in the potential range of 1.0 to 3.0 V, which is higher than other previously reported Nb 2 O 5 -based electrode. The synergistic effects from the nanopillar morphology, high electronic conductivity and stable structure promise potential applications in high-security and high-rate capability Li-ion batteries. Scheme 1. Schematic of the synthesis of TT-Nb 2 O 5 nanopillars.