Hierarchical nickel sulphide microstructures for controlled water disinfection and cold cathode emission

Abstract

Hierarchical nickel sulphide microtubes were prepared by cost effective sol-gel technique with tuning of morphology and applied for photo-induced hazardous dye segregation and cold electron emission. The synthesized samples were characterized for crystalline phase, morphology and composition via X-ray diffractometry, electron microscopy and energy dispersive X-ray studies respectively. The band gaps were estimated from UV–vis data. The samples were found to be effective as a dye degrading agent under UV irradiation. The pollutant removal efficiency of the nickel sulphide (NS) microstructures was found to be governed by dimension and compositional parameters jointly. The sample showing highest degradation efficiency was found to degrade phenol effectively. Scavenger test was carried out to identify the active radicals involved in the catalysis process. To ensure long term action of the catalyst sample, recyclability of the same was investigated thoroughly. The NS microstructures also showed field emission behaviour which is reported for the first time. The growth of different shapes and hierarchical units of NS structures was correlated with stoichiometric alteration which may also be extended for synthesis of other nickel chalcogenides.