Synthesis of ZnO/NiO hollow spheres and their humidity sensing performance

Xie, Xiujuan; Si, Renjun; Zheng, Jun; Wei, Kai; Zheng, Xiu‐Ying; Chen, Cheng; Chun-chang, Wang

doi:10.1016/j.jallcom.2021.160487

Cited by 18 publications

(12 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, the introduction of oxygen vacancies not only improves the separation efficiency of optical carriers as trap centers, but also produces defect-related states near the valence band, resulting in a narrower band gap and enhanced light absorption. In fact, the doping of Ni 2+ and the appropriate oxygen vacancy concentration promote the production of •O 2− to a certain extent [ 35 ]. It is generally believed that the increase in oxygen vacancy concentration is beneficial to the capture of photogenerated electrons, thus improving the separation ability of photogenerated electrons and holes, and promoting the photocatalytic degradation of dyes and antibiotics into CO 2 and H 2 O [ 33 ].…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, the formation of a p–n heterojunction at the interface between n-type ZnO and p-type NiO plays an important role in improving the performance. Due to the difference in band gap and Fermi level between the p-type NiO and n-type ZnO, they form a p–n heterojunction at the interface through charge carrier transport, thus increasing the barrier height and generating an additional depletion region [ 35 ]. As a result, the p–n heterojunction formed when the composite is exposed to air enables the sensor to exhibit a higher resistance.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Zhang

2022

Nanomaterials

View full text Add to dashboard Cite

In this paper, ZnO/NiO composites rich in oxygen vacancies are prepared by the solvothermal method and reduction method. In the test, through the use of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscope (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and electron paramagnetic resonance (EPR), we effectively prove the existence of phase, morphology and oxygen vacancies in the material. Through the photocatalysis test and gas sensitivity test, it is found that 10% Ni doped OZN-10 has the best photocatalytic activity and gas sensitivity characteristics. The degradation rate of methylene blue (MB) was 98%. The gas sensitivity test shows that OZN-10 has good selectivity, good response performance (3000 ppm, 27,887%) and excellent response recovery time (response time: 50 s, recovery time: 5–7 s) for saturated NH3 gas at standard atmospheric pressure (101.325 KPa) and room temperature (25 °C). The synergistic effect of oxygen vacancy as the center of a trap and p–n heterojunction forming an electric potential field at the interface is explained, and the mechanism of improving photocatalysis and gas sensitivity is analyzed. This work will provide an innovative vision for dual-performance oxygen vacancy modification of heterojunctions through photocatalysis.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Zhang

2022

Nanomaterials

View full text Add to dashboard Cite

show abstract

“…In addition, a heterojunction will form between g-C 3 N 4 nanosheets and TiO 2 nanoparticles, which can play an important role in humidity detection . When the g-C 3 N 4 and TiO 2 are contacted, electrons can migrate from TiO 2 to g-C 3 N 4 until the Fermi level reaches equilibrium, resulting in a wild depletion layer at the interface between the two semiconductor materials as well as a high impedance state (Figure e) .…”

Section: Results and Discussionmentioning

confidence: 99%

Humidity Sensing by Graphitic Carbon Nitride Nanosheet/TiO₂ Nanoparticle/Ti₃C₂T_x Nanosheet Composites for Monitoring Respiration and Evaluating the Waxing of Fruits

Guo

Kuang

Zhu

et al. 2021

ACS Appl. Nano Mater.

View full text Add to dashboard Cite

Relative humidity (RH) is an important physical quantity in industry, agriculture, and medical treatment. However, it is still challenging to exploit high-performance humidity sensors that can meet the detection requirement for responding to both high humidity variation and low humidity variation. In this work, ternary graphitic carbon nitride (g-C 3 N 4 ) nanosheet/TiO 2 nanoparticle/Ti 3 C 2 T x nanosheet composites were synthesized by in situ oxidation and thermal polymerization. The response of the g-C 3 N 4 /TiO 2 /Ti 3 C 2 T x sensor reaches 531 from 11−95% RH, which enhances 4, 11, and 450 times compared with that of TiO 2 , g-C 3 N 4 , and TiO 2 /Ti 3 C 2 T x sensors. Moreover, the ternary g-C 3 N 4 /TiO 2 /Ti 3 C 2 T x sensor demonstrates excellent reproducibility, fast response speed, low hysteresis loop, and good anti-interference ability. The as-fabricated g-C 3 N 4 /TiO 2 /Ti 3 C 2 T x sensor is further utilized in practical applications for human respiration detection and evaluation of waxing of fruits. The test results show that our fabricated sensor is capable of precisely sensing breathing status and distinguishing the waxing of fruits. In addition, our sensor can be used in most application scenarios and accelerate the integration of the Internet of Things (IoT).

show abstract

“…To adapt to the low-temperature resistance of plastic food packaging, we developed a low-temperature process based on NIR laser annealing to produce the SnO 2 -sensing layer. A literature survey reveals that metal oxide semiconductors (ZnO, SnO 2 , ITO, WO 3 , CuO, NiO) [31][32][33][34][35][36] are good candidates for humidity sensing. Metal oxide semiconductor (MOx)-based humidity sensors can be fabricated with a low-cost solution process to exhibit high sensitivity and a fast response [37].…”

Section: Introductionmentioning

confidence: 99%

SnO2-Based Ultra-Flexible Humidity/Respiratory Sensor for Analysis of Human Breath

et al. 2023

View full text Add to dashboard Cite

Developing ultraflexible sensors using metal oxides is challenging due to the high-temperature annealing step in the fabrication process. Here, we demonstrate the ultraflexible relative humidity (RH) sensor on food plastic wrap by using 808 nm near-infrared (NIR) laser annealing for 1 min at a low temperature (26.2–40.8 °C). The wettability of plastic wraps coated with sol-gel solution is modulated to obtain uniform films. The surface morphology, local temperature, and electrical properties of the SnO2 resistor under NIR laser irradiation with a power of 16, 33, and 84 W/cm2 are investigated. The optimal device can detect wide-range RH from 15% to 70% with small incremental changes (0.1–2.2%). X-ray photoelectron spectroscopy reveals the relation between the surface binding condition and sensing response. Finally, the proposed sensor is attached onto the face mask to analyze the real-time human breath pattern in slow, normal, and fast modes, showing potential in wearable electronics or respiration monitoring.

show abstract

Synthesis of ZnO/NiO hollow spheres and their humidity sensing performance

Cited by 18 publications

References 60 publications

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Humidity Sensing by Graphitic Carbon Nitride Nanosheet/TiO₂ Nanoparticle/Ti₃C₂T_x Nanosheet Composites for Monitoring Respiration and Evaluating the Waxing of Fruits

SnO2-Based Ultra-Flexible Humidity/Respiratory Sensor for Analysis of Human Breath

Contact Info

Product

Resources

About

Synthesis of ZnO/NiO hollow spheres and their humidity sensing performance

Cited by 18 publications

References 60 publications

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

The Oxygen Vacancy Defect of ZnO/NiO Nanomaterials Improves Photocatalytic Performance and Ammonia Sensing Performance

Humidity Sensing by Graphitic Carbon Nitride Nanosheet/TiO2 Nanoparticle/Ti3C2Tx Nanosheet Composites for Monitoring Respiration and Evaluating the Waxing of Fruits

SnO2-Based Ultra-Flexible Humidity/Respiratory Sensor for Analysis of Human Breath

Contact Info

Product

Resources

About

Humidity Sensing by Graphitic Carbon Nitride Nanosheet/TiO₂ Nanoparticle/Ti₃C₂T_x Nanosheet Composites for Monitoring Respiration and Evaluating the Waxing of Fruits