Formation of shape-selective magnetic cobalt oxide nanowires: environmental application in catalysis studies

Abstract

A new route for the formation of shape-selective CoO nanowires has been developed using a simple microwave (MW) heating method. The reduction of Co(II) ions was done using a new reducing agent alkaline 2,7-dihydroxy naphthalene (2,7-DHN) in cetyltrimethylammonium bromide (CTAB) micellar media.The reaction mixture was irradiated using MW for a total time of 6 min. The process exclusively generates CoO nanowires of different lengths and having diameter y5 ¡ 2 nm to 15 ¡ 2 nm range just by tuning the metal-ion-to-surfactant molar ratios and changing the other reaction parameters. Magnetization measurements indicate that there is no observable coercivity for the short nanowires, but the coercivity increases as the length of the nanowires increases although the magnetic moment values at the maximum applied magnetic field of 2 T decreased with an increase in the length of the nanowires. The synthesized CoO nanowires are found to serve as an effective catalyst for the mineralization of several organic dye molecules in the presence of NaBH 4 in a short reaction time. The process assists the room temperature mineralization of the dyes and provides a cleanup measure of dye contaminated water bodies even in the presence or in the absence of light. The yield of the CoO nanowires with uniform shapes is found to be significantly high (.95%) and the nanowires are stable for more than a month under ambient conditions.The proposed synthesis method is efficient, straightforward, reproducible, and robust. Other than in catalysis, the cobalt oxide nanomaterials can also be applied for making pigments, lithium-ion battery materials, solid state sensors, or as anisotropy source for magnetic recording.

Enhanced catalytic and SERS activities of CTAB stabilized interconnected osmium nanoclusters

“…Most of the peaks described above bear similarity to earlier reports for CTAB capped metal nanostructures. 3,36 So from the above FT-IR analysis, it is clear that Os NCs are stabilized by the CTAB molecule probably via the Os-N bond formation due to the presence of an ammonium ion on its surface by forming a double layer arrangement.…”

“…In last few years the study on materials mainly at nanoscale dimensions found tremendous importance due to their unusual electronic, 1 catalytic, 2 magnetic, 3 optical properties 4 as compared to their bulk counterparts. So a burst of research activities has been seen in recent years for the synthesis and characterization of metal nanoparticles (NPs) and their possible application in different interdisciplinary fields.…”

Microwave Synthesis of SnWO4 Nanoassemblies on DNA Scaffold: A Novel Material for High Performance Supercapacitor and as Catalyst for Butanol Oxidation

“…Kundu et al reported earlier the synthesis of metal and metal oxide nanomaterials using microwave heating routes within relatively lower reaction time. [34][35][36][37][38] To the best of our knowledge and from the careful literature search, there is no report for the formation of self-assembled, aggregated SnWO 4 nano-assemblies in DNA scaffold within a couple of minutes of microwave heating.…”

Hetero–nanostructured Ni/α‐Mn2O3 as Highly Active Catalyst for Aqueous Phase Reduction Reactions

“…This observation remarks the quick reduction of dye pollutants in presence of NaBH 4 over Ni/α‐Mn 2 O 3 catalyst. Further, a comparative study is carried out on the metal based reduction of dye by NaBH 4 and it is found that the rate constant of Ni/α‐Mn 2 O 3 catalyzed reactions are superior than literatures that reported earlier (Table ) …”