Uniform Mn(2)O(3) octahedral nanoparticles were synthesized by a mediated N, N-dimethylformamide (DMF) solvothermal route. On the basis of a time-dependent experiment, we propose that the Mn(2)O(3) octahedra were formed through oriented aggregation of primary nanocrystals. Meanwhile, poly(vinyl-pyrrolidone) (PVP) was applied as a surfactant to facilitate the oriented aggregation of small Mn(2)O(3) nanoparticles into octahedral crystallites. By tuning the amount of Mn(NO(3))(2), particles with average sizes 1 µm to 300 nm, with a narrow size distribution, could be fabricated. The catalytic test results show that the as-obtained Mn(2)O(3) octahedra exhibited desirable CO catalytic oxidation properties and the surface texture and particle size significantly affected the catalytic activity. By contrast, the larger Mn(2)O(3) octahedral nanoparticles prepared at a lower concentration of Mn(NO(3))(2) exhibited relatively high activities.

The hypochromic effect of bromocresol green (BCG) resulted from long-chained imidazolium ionic liquids was investigated. The hypochromic effect may be caused by the formation of the neutral complex [C_nmim]₂ ⁺[BCG]²⁻via electrostatic interaction and hydrophobic interaction. Based on the spectral characteristics, a new method for determination of long-chained imidazolium ionic liquids is developed. The proposed method can be performed using a UV-vis spectrophotometer, at the optimum λ_min. Beer's law is obeyed in the concentration range of 0.004–0.04 mmol L⁻¹ for [C₁₄mim]Br and [C₁₆mim]Cl, and the detection limits are 0.0011 and 0.00095 mmol L⁻¹ for [C₁₄mim]Br and [C₁₆mim]Cl, respectively. Meanwhile, precision, accuracy and tolerance are also very good. The method is fast, economical and does not require organic solvents; it can be applied for determination of long-chained imidazolium ionic liquids.

Hollow porous AuAg nanospheres (AuAg HPNSs) were obtained through a simple solvothermal synthesis, complemented by a dealloying strategy. The hollow interior, open pore voids, and integral interconnected skeleton shell in AuAg HPNSs are beneficial for providing sufficient electrolyte diffusion and contacts, abundant active sites, and efficient electron transport. This specific structure and the favorable alloy synergism contribute to the superior electrocatalytic activity toward dopamine (DA) and acetaminophen (AC). AuAg HPNSs show high sensitivity, good selectivity, excellent sensing durability, and outstanding repeatability for amperometric assays of AC and DA. In particular, the AuAg-based sensors achieve effective ultrasensitive simultaneous analyses of AC and DA, exhibiting the characteristics of the wide linear range and low detection limit. With their prominent electrocatalytic activity and simple preparation methods, AuAg HPNSs present broad application prospects for constructing a highly responsive electrochemical sensing system.