Effect Of Field On The Morphology Of Nickel Oxide In Liquid Phase Synthesis

Nickel oxide has been widely applied in catalysts, super capacitor, gas sensor, functional ceramic materials, special coatings, optical absorption materials and other fields as a kind of functional material with the excellent properties of electrochemical activity and electricity light, heat-sensitive and catalytic. Many methods was gradually developed to prepare nickel oxide power with spherical morphology and narrow particle size distribution, such as a single microwave thermal bonding method, organic complexes precursor method, spray pyrolysis, sol-gel and micro-emulsion, and so on. The research to get nickel oxide power are mainly by single microwave or ultrasonic assisted synthesis, however, combined microwave with ultrasonic has not yet been reported in the literature. Therefore, preparation of ultrafine nickel oxide by liquid-phase coprecipitation method that assisted by microwave and ultrasonic, main works and achievements are as follows:Ni Cl2·6H2O as raw materials, CO(NH2)2 and C2H2O4 as the precipitation agent, study the effect of reaction conditions on the morphology and particle size of nickel oxide precursor. The reaction conditions included heating mode, initial concentration of Ni Cl2, reaction temperature, reaction time, the ratio of reaction, ageing time, modifiers. The results showed that preparation of ultrafine nickel oxide by liquid-phase coprecipitation method that assisted by microwave and ultrasonic was better than a single microwave mode and normal temperature water bath mode; The morphology of ball and block of nickel oxide precursor was prepared when CO(NH2)2 and C2H2O4 as the precipitation agent.Nickel oxide precursor with spherical and good dispersion can be prepared by microwave and ultrasonic synergy. The conditions were that [Ni2+]=0.1 mol·L-1, CO(NH2)2=1 mol·L-1, temperature is 90℃, time is 120 min, aging time 0 h. PVP as the Modifier, the effect is not obvious to improve the reunion of nickel oxide precursor. The morphology of nickel oxide precursor was better in the microwave oven adopting low dry 90 min.Nickel oxide precursor was prepared by microwave and ultrasonic synergy in the optimal conditions and focus on the effect of different annealing temperatures and holding time on morphology and particle size of nickel oxide power. The TG-DTA,XED,FT-IR results showed that cubic model of Ni O powder formed when temperature is above 300℃,and then crystal shape of Ni O powders is more complete with the increasing temperature. The SEM results showed that Ni O power with needle shape, crystalline integrity, good dispersion, narrow particle size distribution, distribution in 0.8~1.5μm range. The results showed that there is no nickel oxide powder generated or incomplete decomposition when the thermal decomposition temperature is too low; powder is easy to appear sintering when the thermal decomposition temperature is too high. Hence, the optimum technology for roasting Ni O precursor was: thermal decomposition temperature is 300 ~ 500℃, holding time is 90 min.