Synthesis And Properties Of Concave Cube Cu₂O

In this paper,by hydrothermal method,we successfully synthesized a concave cubic Cu₂O nanomaterial with a high refractive index exposed surface using two different precursor reagents.The obtained Cu₂O material has good monodispersity,highly symmetrical morphology,and has a high refractive index exposed surface.By changing reaction time and the concentration of the sodium citrate solution,the formation mechanism of concave cube Cu₂O was explored in detail.Copper acetate as the reaction precursor,concave cubic Cu₂O was prepared by a top-down synthesis strategy.Due to the different adsorption of oxygen to different crystal planes of Cu₂O,the{100}crystal plane is selectively oxidized and etched with the extension of the reaction time.Finally,concave cubic Cu₂O nanomaterial was obtained.In addition,copper sulfate as the reaction precursor,concave cubic Cu₂O was prepared by a bottom-up synthesis strategy.The{100}surface is covered by citrate ions during the growth of Cu₂O and the surface growth rate is slow,and the crystal grows along the<111>direction.Finally,new inclined planes are formed,and concave cubic Cu₂O nanomaterial is also prepared.After that,we conducted gas-sensitivity and photocatalytic performance studies on the prepared materials,and the results are as follows:(1)Gas-sensing performance:The sensors based concave cubic Cu₂O are used for NO₂ gas-sensing detection at a working temperature of 150°C.The gas detection concentrations range from 1 ppb to 10 ppm and the minimum detection limit is 1 ppb.When the sample exposed to4 ppm NO₂ gas,the response/recovery time is less than 60 s(both response and recovery time are relatively fast).At the same time,there is a good linear relationship between response and NO₂ gas concentration.Therefore,the concave cube Cu₂O has good gas sensitivity to NO₂ gas.(2)Photocatalytic performance study:Cu₂O catalyst was used for photocatalytic degradation experiments on the three dyes methyl orange(MO),methylene blue(MB)and Congo red(CR)at the same concentration(30 mg/L).The experimental results showed that the photodegradation rate of Cu₂O to MO and MB dyes was 7.07 and 19.84%in 45 minutes,and the photodegradation rate of CR in 30 minutes was 92.8%,indicating good photocatalytic performance.Finally,by replacing sodium citrate with sodium carbonate,we synthesized Cu O nanospheres.The gas property of Cu O nanospheres to NO₂ gas was also tested.The results show that in the concentration range of 0.1-10 ppm,Cu O nanospheres have good response to NO₂.