Porous Zn O was obtained by hydrothermal method. The results of scanning electron microscope revealed the porous structure in the as-prepared materials. The acetone sensing test results of porous Zn O show that porous...Porous Zn O was obtained by hydrothermal method. The results of scanning electron microscope revealed the porous structure in the as-prepared materials. The acetone sensing test results of porous Zn O show that porous Zn O possesses excellent acetone gas sensing properties. The response is 35.5 at the optimum operating temperature of 320？C to 100 ppm acetone. The response and recovery times to 50 ppm acetone are 2 s and 8 s, respectively. The lowest detecting limit to acetone is 0.25 ppm, and the response value is 3.8. Moreover, the sensors also exhibit excellent selectivity and long-time stability to acetone.展开更多
In this paper,a simple and cheap method to prepare porous ZnO by using zinc nitrate,ethanol and triethanolamine(TEA)is reported.The as-prepared sample consisted of nano and micro pores.The sample was calcined at 300℃...In this paper,a simple and cheap method to prepare porous ZnO by using zinc nitrate,ethanol and triethanolamine(TEA)is reported.The as-prepared sample consisted of nano and micro pores.The sample was calcined at 300℃,400℃and 500℃with different heating rates.At 500℃,the nano pores disappeared but the sample maintained its micro porosity.Field emission scanning electron microscopy(FE-SEM)pictures confirmed that the size and growth of ZnO nanoparticles depended on the heating conditions.The infrared(IR)absorption peak of Zn-O stretching vibration positioned at 457 cm^(-1)was split into two peaks centered at 518 cm^(-1)and 682 cm^(-1)with the change of morphology.These results confirmed that Fourier transform infrared(FT-IR)spectrum was sensitive to variations in particle size,shape and morphology.The photoluminescence(PL)spectrum of porous ZnO contained five emission peaks at 397 nm,437 nm,466 nm,492 nm and 527 nm.Emission intensity enhanced monotonously with increase of temperature and the change was rapid between temperatures of 300℃and 500℃.This was due to the elimination of organic species and improvement in the crystallanity of the sample at 500℃.展开更多
Porous ZnO films were prepared by electrodeposition method in zinc nitrate aqueous solution using ITO glass covered with polystyrene sphere （PS） colloidal crystal arrays as substrates. The preparation procedure incl...Porous ZnO films were prepared by electrodeposition method in zinc nitrate aqueous solution using ITO glass covered with polystyrene sphere （PS） colloidal crystal arrays as substrates. The preparation procedure includes two parts： deposition of ZnO in the interstices of the colloidal crystals and subsequent removal of the PS templates. The influences of deposition potential and temperature on the ZnO films were investigated. The ordered, uniform porous ZnO films with optical transmittance of approximately 63.6% at 600 nm could be obtained when the deposition potential and temperature were –1.1 V and 70 ℃, respectively. The optical band gap energy increased along with the absolute deposition potential and temperature, ranging from 3.33 to 3.43 eV and from 3.35 to 3.42 eV, respectively.展开更多
Realizing the real-time detection of CH4 is important for the safety of human life.A facile hydrothermal method was used to synthesize Ag nanoparticlesdecorated ZnO porous nanoflakes(PNFs)in this study.The characteriz...Realizing the real-time detection of CH4 is important for the safety of human life.A facile hydrothermal method was used to synthesize Ag nanoparticlesdecorated ZnO porous nanoflakes(PNFs)in this study.The characterization results confirmed that Ag nanoparticles had been decorated in ZnO nanoflakes with the thickness of~10 nm.The gas-sensing properties of Ag-decorated ZnO nanoflakes were also investigated.While the gas-sensing performances of ZnO were remarkably improved by decorating Ag nanoparticles on the surface of ZnO nanoflakes,the response of the Agdecorated ZnO sensor to 3000 ppm CH4 is almost 1.3 times as high as that of pristine ZnO sensor.The obtained Ag/ZnO sensor exhibits better long-term stability and shorter response recovery time(5/38 s)in the comparison with pristine ZnO,demonstrating the possibility for the actual detection of CH4.The enhanced CH4 sensing performance can be attributed to the synergism between the unique hierarchical porous structure and the sensitizing actions utilized by the Ag nanoparticles.展开更多
基金Projected supported by the Project of Challenge Cup for College Students,China(Grant No.450060497053)
文摘Porous Zn O was obtained by hydrothermal method. The results of scanning electron microscope revealed the porous structure in the as-prepared materials. The acetone sensing test results of porous Zn O show that porous Zn O possesses excellent acetone gas sensing properties. The response is 35.5 at the optimum operating temperature of 320？C to 100 ppm acetone. The response and recovery times to 50 ppm acetone are 2 s and 8 s, respectively. The lowest detecting limit to acetone is 0.25 ppm, and the response value is 3.8. Moreover, the sensors also exhibit excellent selectivity and long-time stability to acetone.
文摘In this paper,a simple and cheap method to prepare porous ZnO by using zinc nitrate,ethanol and triethanolamine(TEA)is reported.The as-prepared sample consisted of nano and micro pores.The sample was calcined at 300℃,400℃and 500℃with different heating rates.At 500℃,the nano pores disappeared but the sample maintained its micro porosity.Field emission scanning electron microscopy(FE-SEM)pictures confirmed that the size and growth of ZnO nanoparticles depended on the heating conditions.The infrared(IR)absorption peak of Zn-O stretching vibration positioned at 457 cm^(-1)was split into two peaks centered at 518 cm^(-1)and 682 cm^(-1)with the change of morphology.These results confirmed that Fourier transform infrared(FT-IR)spectrum was sensitive to variations in particle size,shape and morphology.The photoluminescence(PL)spectrum of porous ZnO contained five emission peaks at 397 nm,437 nm,466 nm,492 nm and 527 nm.Emission intensity enhanced monotonously with increase of temperature and the change was rapid between temperatures of 300℃and 500℃.This was due to the elimination of organic species and improvement in the crystallanity of the sample at 500℃.
基金Funded by the Key Project of Chinese Ministry of Education (No. 208008)China Postdoctoral Science Foundation Funded Project (No. 20080440674)
文摘Porous ZnO films were prepared by electrodeposition method in zinc nitrate aqueous solution using ITO glass covered with polystyrene sphere （PS） colloidal crystal arrays as substrates. The preparation procedure includes two parts： deposition of ZnO in the interstices of the colloidal crystals and subsequent removal of the PS templates. The influences of deposition potential and temperature on the ZnO films were investigated. The ordered, uniform porous ZnO films with optical transmittance of approximately 63.6% at 600 nm could be obtained when the deposition potential and temperature were –1.1 V and 70 ℃, respectively. The optical band gap energy increased along with the absolute deposition potential and temperature, ranging from 3.33 to 3.43 eV and from 3.35 to 3.42 eV, respectively.
基金the National Natural Science Foundation of China(U1704255,62101177)the fellowship of China Postdoctoral Science Foundation(2021M690919)+1 种基金the Youth Project of Natural Science Foundation of Henan Province(212300410149)the Key Scientific Research Project of Colleges and University in Henan Province(21A430019).
文摘Realizing the real-time detection of CH4 is important for the safety of human life.A facile hydrothermal method was used to synthesize Ag nanoparticlesdecorated ZnO porous nanoflakes(PNFs)in this study.The characterization results confirmed that Ag nanoparticles had been decorated in ZnO nanoflakes with the thickness of~10 nm.The gas-sensing properties of Ag-decorated ZnO nanoflakes were also investigated.While the gas-sensing performances of ZnO were remarkably improved by decorating Ag nanoparticles on the surface of ZnO nanoflakes,the response of the Agdecorated ZnO sensor to 3000 ppm CH4 is almost 1.3 times as high as that of pristine ZnO sensor.The obtained Ag/ZnO sensor exhibits better long-term stability and shorter response recovery time(5/38 s)in the comparison with pristine ZnO,demonstrating the possibility for the actual detection of CH4.The enhanced CH4 sensing performance can be attributed to the synergism between the unique hierarchical porous structure and the sensitizing actions utilized by the Ag nanoparticles.
