Synthesis of NiO hollow nanospheres via Kirkendall effect and their enhanced gas sensing performance

Chu, Shasha; Yang, Chao; Su, Xintai

doi:10.1016/j.apsusc.2019.06.226

Cited by 38 publications

(8 citation statements)

References 42 publications

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“…The proposed gas sensing mechanism is as follows and shown in Figure e. During the air exposure, the oxygen gas in the ambient atmosphere adsorbs on the NiO surface and captures the electron from the near surface. , As NiO shows a p -type sensing behavior in which the charge concentration is dominated by holes, the withdrawal of electrons from NiO increases the unpaired holes, creating the hole accumulation layers (HALs) on the surface. , The HALs effectively decrease the interfacial grain boundary resistance and the potential barrier, resulting in the elevation of the electron mobility drifted by the current from the measurement system. Thus, under ambient air, NiO possesses low electrical resistance.…”

Section: Results and Discussionmentioning

confidence: 99%

Impact of Surface Faceting on Gas Sensing Selectivity of NiO: Revealing the Adsorption Sites of Organic Vapors on the {111} Facet

et al. 2022

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Air pollution by volatile organic compounds (VOCs) has been responsible for the decline of human health and environmental quality. NiO-based materials hold great promise as high-performance sensing materials to monitor the VOC concentration in air. The present research focuses on the design of NiO nanocrystals and the investigation of the effect of surfaceterminated facets on their VOC gas sensing selectivity. NiO nanoparticles (NPs) with no specific surface facet exhibited a poor responsivity and selectivity toward VOC detection at all observed working temperatures, while the octahedral morphology of NiO exposed to the {111} facet demonstrated a better VOC sensing responsivity (R g /R a = 6.2) and high selectivity toward toluene at 250 °C. Owing to the terminated Ni metal as the highly reactive adsorption site, the octahedral morphology of NiO with the {111} facet exhibited an improved sensing and selectivity performance. Based on the experimental evidence, an ab initio DFT calculation is performed to investigate the analyte adsorption on the {111} facet of NiO and explain the high toluene selectivity on this facet. It is revealed that the {111} facet is energetically favorable for toluene adsorption, with an energy adsorption (E ads ) of −3.927 eV at the hollow HCP site. This study has a significant potentiality to be extended to many surface phenomena such as sensors, catalysis, and energy storage.

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Section: Results and Discussionmentioning

confidence: 99%

Impact of Surface Faceting on Gas Sensing Selectivity of NiO: Revealing the Adsorption Sites of Organic Vapors on the {111} Facet

et al. 2022

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“…The interior of the hollow structure can also serve as a microreaction chamber, providing a place for gas molecules to react with sensitive materials, and a short distance for carrier transport. For the hollow structure of NiO, NiO hollow nanofibers [70] and hollow spheres [71][72][73][74][75] have been reported, and they have [76,77]. Furthermore, the {111} planes of NiO have a greater number of unsaturated O atoms and a higher surface energy than the usually exposed {220} planes, which is beneficial for sensitive performance [78,79].…”

Section: Morphologymentioning

confidence: 99%

NiO-Based Gas Sensors for Ethanol Detection: Recent Progress

Zeng

2022

Journal of Sensors

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In this review, we summarized the state-of-the-art progress on the ethanol performance of NiO by means of morphology, doping, loading noble metal particles, and forming heterojunctions. We first introduced the effect of modulating NiO morphology on ethanol performance that has been reported in recent years. The morphology with large specific surface area and high porosity was considered to be the one that can bring high gas response. Then, we discussed the enhanced effect of the doping of metal cations and noble metal particle loading on the ethanol-sensitive properties of NiO. Doping ions increased the ground-state resistance and increased the oxygen defect concentration of NiO. The effects of noble metal particles on the performance of NiO included chemical sensitization and electronic sensitization. Finally, the related contents of NiO forming complexes with metal oxides and bimetallic oxides were discussed. In this section, the specific improvement mechanism was discussed first, and then, the related work of researchers in recent years was summarized. At the same time, we presented a reasonable outlook for NiO-based ethanol sensors, imagining future directions.

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“…However, the smaller the grain size, the higher the specific surface area and the more reaction sites [103]. As a result, the grain size of the gas-sensitive layer is generally at the nanoscale [104], such as nanospheres, nanowires, nanobelts [105][106][107], etc. However, the smaller the grain size, the lower the critical temperature of grain growth, and the working temperature of sensors can usually reach 200-600 ℃ [108].…”

Section: Gas-sensitive Coatingsmentioning

confidence: 99%

Micro-nano structured functional coatings deposited by liquid plasma spraying

Huan

et al. 2020

J Adv Ceram

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Inspired by the micro-nano structure on the surface of biological materials or living organisms, micro-nano structure has been widely investigated in the field of functional coatings. Due to its large specific surface area, porosity, and dual-scale structure, it has recently attracted special attention. The typical fabrication processes of micro-nano structured coatings include sol-gel, hydrothermal synthesis, chemical vapor deposition, etc. This paper presents the main features of a recent deposition and synthesis technique, liquid plasma spraying (LPS). LPS is an important technical improvement of atmospheric plasma spraying. Compared with atmospheric plasma spraying, LPS is more suitable for preparing functional coatings with micro-nano structure. Micro-nano structured coatings are mainly classified into hierarchical-structure and binary-structure. The present study reviews the preparation technology, structural characteristics, functional properties, and potential applications of LPS coatings with a micro-nano structure. The micro-nano structured coatings obtained through tailoring the structure will present excellent performances.

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Synthesis of NiO hollow nanospheres via Kirkendall effect and their enhanced gas sensing performance

Cited by 38 publications

References 42 publications

Impact of Surface Faceting on Gas Sensing Selectivity of NiO: Revealing the Adsorption Sites of Organic Vapors on the {111} Facet

Impact of Surface Faceting on Gas Sensing Selectivity of NiO: Revealing the Adsorption Sites of Organic Vapors on the {111} Facet

NiO-Based Gas Sensors for Ethanol Detection: Recent Progress

Micro-nano structured functional coatings deposited by liquid plasma spraying

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