La3＋ doped ZnO nano-rods with different doping concentration were prepared via solvothermal method.The doped ZnO nano-rods were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）,respec...La3＋ doped ZnO nano-rods with different doping concentration were prepared via solvothermal method.The doped ZnO nano-rods were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）,respectively.The effect of La3＋ doping on the gas-sensing properties was investigated.The results revealed that the sensor based on 6 mol% La3＋ doped ZnO nano-rods exhibited high response to dilute acetone,and the responses to 0.01×10-6 acetone reached 2.4 when operating at 425 ℃.The response time and the recovery time for 0.01×10-6 acetone were only 16 and 3 s,respectively.展开更多
Wurtzite hexagonal ZnO semiconductor nano-rods (NRs) thin films were grown on silicon substrates and silver wire with diameter equal 68 nm. Sol gel (SG) and aqueous chemical growth (ACG) methods by two steps of prepar...Wurtzite hexagonal ZnO semiconductor nano-rods (NRs) thin films were grown on silicon substrates and silver wire with diameter equal 68 nm. Sol gel (SG) and aqueous chemical growth (ACG) methods by two steps of preparation (seed layers and nano-rod growth) are used for samples preparation. The structural and morphological properties are evaluated using X-ray diffraction (XRD) and scanning electron microscope (SEM). The proposed iron ion sensor has shown good linearity for a wide concentration range from 0.078 M/L to 0.26 M/L of iron ions. The results show that the electrode is highly sensitive to iron ions with a slope around 47.8 mV/decade with a regression coefficient R2 = 0.96.展开更多
In modern ZnO varistors,traditional aging mechanisms based on increased power consumption are no longer relevant due to reduced power consumption during DC aging.Prolonged exposure to both AC and DC voltages results i...In modern ZnO varistors,traditional aging mechanisms based on increased power consumption are no longer relevant due to reduced power consumption during DC aging.Prolonged exposure to both AC and DC voltages results in increased leakage current,decreased breakdown voltage,and lower nonlinearity,ultimately compromising their protective performance.To investigate the evolution in electrical properties during DC aging,this work developed a finite element model based on Voronoi networks and conducted accelerated aging tests on commercial varistors.Throughout the aging process,current-voltage characteristics and Schottky barrier parameters were measured and analyzed.The results indicate that when subjected to constant voltage,current flows through regions with larger grain sizes,forming discharge channels.As aging progresses,the current focus increases on these channels,leading to a decline in the varistor’s overall performance.Furthermore,analysis of the Schottky barrier parameters shows that the changes in electrical performance during aging are non-monotonic.These findings offer theoretical support for understanding the aging mechanisms and condition assessment of modern stable ZnO varistors.展开更多
Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low ...Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low concentrations becomes critical for both environmental monitoring and human health. In this study, a novel Eu/Ce-codoped MOF-ZnO gas sensor was developed for the sensitive detection of n-butanol gas under ultraviolet activation at ambient temperature. A series of Eu/Ce-ZnO nanomaterials were synthesized via a simple co-precipitation route, by carefully designing the varied mass ratios of Eu and Ce incorporated into pristine ZnO derived from MOF precursors. The gas testing results revealed that introducing an appropriate amount of Eu and Ce would enlarge the specific surface area and enrich the oxygen vacancy content compared to pristine MOF-ZnO. Upon UV irradiation, the 0.03 wt% Eu 0.04 wt% Ce-ZnO sensor achieved a superior response of 611 for100 ppm n-butanol at room temperature, 15.28 times higher than that of pristine MOF-ZnO(40). Furthermore, the sensor presented rapid response/recovery times(15 s/28 s) and excellent selectivity. The above contributions pave the way for the promising development of highly sensitive, ultraviolet-enhanced gas sensors for ambient temperature detection of VOCs.展开更多
The photocatalytic oxidation of methane(CH_(4)) to valuable chemicals like low alcohols(CH_(3)OH and C_(2)H_(5)OH) represents a significant technological advancement with implications for energy conversion and environ...The photocatalytic oxidation of methane(CH_(4)) to valuable chemicals like low alcohols(CH_(3)OH and C_(2)H_(5)OH) represents a significant technological advancement with implications for energy conversion and environmental purification.A major challenge in this field is the chemical inertness of methane and the strong oxidizing nature of photogenerated holes,which can lead to over-oxidation and reduced selectivity and efficiency.To address these issues,we have developed a sodium-doped zinc oxide(Na-ZnO) modified with cobalt oxide(CoO) catalyst.This catalyst has demonstrated excellent performance in converting methane to low alcohols,achieving a yield of 130 μmol g^(-1)h^(-1) and a selectivity of up to 96 %.The doping of Na in ZnO significantly enhances methane adsorption,while the surface-modified CoO effectively captures photogenerated holes,activates water molecules,and uses hydroxyl radicals to activate methane,thus controlling the dehydrogenation degree of methane and preventing the formation of over-oxidized products.This strategy has successfully improved the efficiency and selectivity of photocatalytic methane oxidation to low alcohols,offering a new perspective for the application of photocatalytic technology in energy and environmental fields.展开更多
基金supported by the project (No.KJ2009A098) sponsored by Education Department of Anhui Provincethe National Natural Science Foundation of China (No. 50975002)
文摘La3＋ doped ZnO nano-rods with different doping concentration were prepared via solvothermal method.The doped ZnO nano-rods were characterized by X-ray diffraction（XRD） and scanning electron microscopy（SEM）,respectively.The effect of La3＋ doping on the gas-sensing properties was investigated.The results revealed that the sensor based on 6 mol% La3＋ doped ZnO nano-rods exhibited high response to dilute acetone,and the responses to 0.01×10-6 acetone reached 2.4 when operating at 425 ℃.The response time and the recovery time for 0.01×10-6 acetone were only 16 and 3 s,respectively.
文摘Wurtzite hexagonal ZnO semiconductor nano-rods (NRs) thin films were grown on silicon substrates and silver wire with diameter equal 68 nm. Sol gel (SG) and aqueous chemical growth (ACG) methods by two steps of preparation (seed layers and nano-rod growth) are used for samples preparation. The structural and morphological properties are evaluated using X-ray diffraction (XRD) and scanning electron microscope (SEM). The proposed iron ion sensor has shown good linearity for a wide concentration range from 0.078 M/L to 0.26 M/L of iron ions. The results show that the electrode is highly sensitive to iron ions with a slope around 47.8 mV/decade with a regression coefficient R2 = 0.96.
文摘In modern ZnO varistors,traditional aging mechanisms based on increased power consumption are no longer relevant due to reduced power consumption during DC aging.Prolonged exposure to both AC and DC voltages results in increased leakage current,decreased breakdown voltage,and lower nonlinearity,ultimately compromising their protective performance.To investigate the evolution in electrical properties during DC aging,this work developed a finite element model based on Voronoi networks and conducted accelerated aging tests on commercial varistors.Throughout the aging process,current-voltage characteristics and Schottky barrier parameters were measured and analyzed.The results indicate that when subjected to constant voltage,current flows through regions with larger grain sizes,forming discharge channels.As aging progresses,the current focus increases on these channels,leading to a decline in the varistor’s overall performance.Furthermore,analysis of the Schottky barrier parameters shows that the changes in electrical performance during aging are non-monotonic.These findings offer theoretical support for understanding the aging mechanisms and condition assessment of modern stable ZnO varistors.
基金supported by the National Natural Science Foundation of China (Grant No. 12304467)the China Postdoctoral Science Foundation (Grant No. 2023M732175)。
文摘Prolonged exposure to n-butanol, a common hazardous volatile organic compound(VOC) in the environment, can lead to a broad range of adverse health effects. Therefore, detecting n-butanol safely and efficiently at low concentrations becomes critical for both environmental monitoring and human health. In this study, a novel Eu/Ce-codoped MOF-ZnO gas sensor was developed for the sensitive detection of n-butanol gas under ultraviolet activation at ambient temperature. A series of Eu/Ce-ZnO nanomaterials were synthesized via a simple co-precipitation route, by carefully designing the varied mass ratios of Eu and Ce incorporated into pristine ZnO derived from MOF precursors. The gas testing results revealed that introducing an appropriate amount of Eu and Ce would enlarge the specific surface area and enrich the oxygen vacancy content compared to pristine MOF-ZnO. Upon UV irradiation, the 0.03 wt% Eu 0.04 wt% Ce-ZnO sensor achieved a superior response of 611 for100 ppm n-butanol at room temperature, 15.28 times higher than that of pristine MOF-ZnO(40). Furthermore, the sensor presented rapid response/recovery times(15 s/28 s) and excellent selectivity. The above contributions pave the way for the promising development of highly sensitive, ultraviolet-enhanced gas sensors for ambient temperature detection of VOCs.
基金support from the Zhejiang Provincial Natural Science Foundation of China (No.LQ24B030011)the Ningbo Natural Science Foundation (No.2023J181)+4 种基金the Open Research Fund of Key Laboratory of Functional Inorganic Materials Chemistry of the Ministry of Education (Heilongjiang University)the Start-up Funding offered by Ningbo University of Technology to J.D.LiNational Natural Science Foundation of China (No.U24A2071)Postdoctoral Research Start-up Fund (No.2111224002)Harbin Normal University Talent Plan (No.1305124213) to Y.D.Liu。
文摘The photocatalytic oxidation of methane(CH_(4)) to valuable chemicals like low alcohols(CH_(3)OH and C_(2)H_(5)OH) represents a significant technological advancement with implications for energy conversion and environmental purification.A major challenge in this field is the chemical inertness of methane and the strong oxidizing nature of photogenerated holes,which can lead to over-oxidation and reduced selectivity and efficiency.To address these issues,we have developed a sodium-doped zinc oxide(Na-ZnO) modified with cobalt oxide(CoO) catalyst.This catalyst has demonstrated excellent performance in converting methane to low alcohols,achieving a yield of 130 μmol g^(-1)h^(-1) and a selectivity of up to 96 %.The doping of Na in ZnO significantly enhances methane adsorption,while the surface-modified CoO effectively captures photogenerated holes,activates water molecules,and uses hydroxyl radicals to activate methane,thus controlling the dehydrogenation degree of methane and preventing the formation of over-oxidized products.This strategy has successfully improved the efficiency and selectivity of photocatalytic methane oxidation to low alcohols,offering a new perspective for the application of photocatalytic technology in energy and environmental fields.
