Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas Detection
Monitoring trace toluene exposure is critical for early-stage lung cancer screening via breath analysis, yet conventional chemiresistive sensors face fundamental limitations, including compromised selectivity in complex VOC matrices and humidity-induced signal drift, with prevailing p–n heterojuncti...
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MDPI AG
2025-04-01
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| author | Dehui Wang Jinwu Hu Hui Xu Ding Wang Guisheng Li |
| author_facet | Dehui Wang Jinwu Hu Hui Xu Ding Wang Guisheng Li |
| author_sort | Dehui Wang |
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| description | Monitoring trace toluene exposure is critical for early-stage lung cancer screening via breath analysis, yet conventional chemiresistive sensors face fundamental limitations, including compromised selectivity in complex VOC matrices and humidity-induced signal drift, with prevailing p–n heterojunction architectures suffering from inherent charge recombination and environmental instability. Herein, we pioneer a 2D core–shell n–n heterojunction strategy through rational design of TiO<sub>2</sub>@MoS<sub>2</sub> heterostructures, where vertically aligned MoS<sub>2</sub> nanosheets are epitaxially grown on 2D TiO<sub>2</sub> derived from graphene-templated synthesis, creating built-in electric fields at the heterojunction interface that dramatically enhance charge carrier separation efficiency. At 240 °C, the TiO<sub>2</sub>@MoS<sub>2</sub> sensor exhibits a superior response (R<sub>a</sub>/R<sub>g</sub> = 9.8 to 10 ppm toluene), outperforming MoS<sub>2</sub> (R<sub>a</sub>/R<sub>g</sub> = 2.8). Additionally, the sensor demonstrates rapid response/recovery kinetics (9 s/16 s), a low detection limit (50 ppb), and excellent selectivity against interfering gases and moisture. The enhanced performance is attributed to unidirectional electron transfer (TiO<sub>2</sub> → MoS<sub>2</sub>) without hole recombination losses, methyl-specific adsorption through TiO<sub>2</sub> oxygen vacancy alignment, and steric exclusion of non-target VOCs via size-selective MoS<sub>2</sub> interlayers. This work establishes a transformative paradigm in gas sensor design by leveraging n–n heterojunction physics and 2D core–shell synergy, overcoming long-standing limitations of conventional architectures. |
| format | Article |
| id | doaj-art-e8eba2cc78b546d0ab73980b23c58169 |
| institution | DOAJ |
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| language | English |
| publishDate | 2025-04-01 |
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| series | Chemosensors |
| spelling | doaj-art-e8eba2cc78b546d0ab73980b23c581692025-08-20T03:14:32ZengMDPI AGChemosensors2227-90402025-04-0113515410.3390/chemosensors13050154Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas DetectionDehui Wang0Jinwu Hu1Hui Xu2Ding Wang3Guisheng Li4School of Materials and Chemistry, University of Shanghai for Science & Technology, Shanghai 200093, ChinaSchool of Materials and Chemistry, University of Shanghai for Science & Technology, Shanghai 200093, ChinaSchool of Materials and Chemistry, University of Shanghai for Science & Technology, Shanghai 200093, ChinaSchool of Materials and Chemistry, University of Shanghai for Science & Technology, Shanghai 200093, ChinaSchool of Materials and Chemistry, University of Shanghai for Science & Technology, Shanghai 200093, ChinaMonitoring trace toluene exposure is critical for early-stage lung cancer screening via breath analysis, yet conventional chemiresistive sensors face fundamental limitations, including compromised selectivity in complex VOC matrices and humidity-induced signal drift, with prevailing p–n heterojunction architectures suffering from inherent charge recombination and environmental instability. Herein, we pioneer a 2D core–shell n–n heterojunction strategy through rational design of TiO<sub>2</sub>@MoS<sub>2</sub> heterostructures, where vertically aligned MoS<sub>2</sub> nanosheets are epitaxially grown on 2D TiO<sub>2</sub> derived from graphene-templated synthesis, creating built-in electric fields at the heterojunction interface that dramatically enhance charge carrier separation efficiency. At 240 °C, the TiO<sub>2</sub>@MoS<sub>2</sub> sensor exhibits a superior response (R<sub>a</sub>/R<sub>g</sub> = 9.8 to 10 ppm toluene), outperforming MoS<sub>2</sub> (R<sub>a</sub>/R<sub>g</sub> = 2.8). Additionally, the sensor demonstrates rapid response/recovery kinetics (9 s/16 s), a low detection limit (50 ppb), and excellent selectivity against interfering gases and moisture. The enhanced performance is attributed to unidirectional electron transfer (TiO<sub>2</sub> → MoS<sub>2</sub>) without hole recombination losses, methyl-specific adsorption through TiO<sub>2</sub> oxygen vacancy alignment, and steric exclusion of non-target VOCs via size-selective MoS<sub>2</sub> interlayers. This work establishes a transformative paradigm in gas sensor design by leveraging n–n heterojunction physics and 2D core–shell synergy, overcoming long-standing limitations of conventional architectures.https://www.mdpi.com/2227-9040/13/5/154heterojunctionTiO<sub>2</sub>@MoS<sub>2</sub>nanosheetsynergistic effectstoluene gas sensor |
| spellingShingle | Dehui Wang Jinwu Hu Hui Xu Ding Wang Guisheng Li Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas Detection Chemosensors heterojunction TiO<sub>2</sub>@MoS<sub>2</sub> nanosheet synergistic effects toluene gas sensor |
| title | Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas Detection |
| title_full | Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas Detection |
| title_fullStr | Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas Detection |
| title_full_unstemmed | Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas Detection |
| title_short | Construction of 2D TiO<sub>2</sub>@MoS<sub>2</sub> Heterojunction Nanosheets for Efficient Toluene Gas Detection |
| title_sort | construction of 2d tio sub 2 sub mos sub 2 sub heterojunction nanosheets for efficient toluene gas detection |
| topic | heterojunction TiO<sub>2</sub>@MoS<sub>2</sub> nanosheet synergistic effects toluene gas sensor |
| url | https://www.mdpi.com/2227-9040/13/5/154 |
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