Table 1 Recent literature on CTAB-assisted metal oxides and PEDOT: PSS for gas sensing.
Method | Materials/system | Key findings | Limitations | Research gap | Ref. |
|---|---|---|---|---|---|
Chemical synthesis routes (hydrothermal, sol–gel, CVD) | 1D oxide nanostructures (ZnO, SnO2, TiO2, etc.) | Discussed control over morphology and crystallinity through different synthesis methods | Did not explore polymer or surfactant-assisted synthesis effects | Need to evaluate surfactant-assisted 1D nanostructures (e.g., CTAB) for improved sensing performance | 2019 |
Inkjet printing and sol–gel synthesis | PEDOT: PSS/ZnO paper-based hydrazine sensor | Demonstrated high flexibility, cost-effectiveness, and good sensitivity for hydrazine detection at room temperature | Limited to liquid-phase sensing; lacks humidity or gas sensing exploration | Integration of PEDOT: PSS/ZnO heterostructures for real-time gas or humidity sensing not yet studied | 2020 |
Review of electroactive hybrid nanocomposites | Organic–inorganic nanocomposites using nanostructured materials | Highlighted enhanced gas sensing due to improved charge mobility and structural porosity | Lacks experimental validation and detailed comparison of hybrid vs. pure oxide sensors | Experimental correlation between morphology, sensitivity, and humidity response remains limited | 2022 |
Hydrothermal method and surface modification | Au-modified SnO2/ZnO composite | Achieved high CO gas sensitivity at room temperature due to Au catalytic activity and SnO2/ZnO heterojunction | Performance analyzed for a single gas; lacks humidity interference study | Study of multi-gas selectivity and humidity effect on SnO2/ZnO heterostructure is still required | 2025 |
Review of heterojunction photocatalysts | Bi-based S/Z heterojunctions | Reviewed Bi-based S/Z-scheme catalysts with efficient charge migration for key photocatalytic reactions. | Provides a solid photocatalytic foundation, opening space to explore S/Z heterojunctions for gas-sensing applications | Need to evaluate S/Z-scheme heterojunctions for enhancing charge separation and gas-sensing behavior | 2025 |
Review of synthesis and characterization techniques | Metal oxide–polymer hybrid composites | Summarized advances in synthesis and multifunctional applications such as sensing, energy storage, and catalysis | Review focused more on synthesis than on interfacial charge transfer mechanisms | Need to investigate synergistic effects between polymers and metal oxides for enhanced sensing selectivity | 2025 |
