Organic-Inorganic Hybrid Materials for Room Temperature Light-Activated Sub-ppm NO Detection

• Main Authors: Abulkosim Nasriddinov, Marina Rumyantseva, Tatyana Shatalova, Sergey Tokarev, Polina Yaltseva, Olga Fedorova, Nikolay Khmelevsky, Alexander Gaskov
• Format: Article
• Language: English
• Published: MDPI AG 2019-12-01
• Series: Nanomaterials
• Subjects: organic–inorganic hybrid materials; tin dioxide; indium oxide; ru (ii) complex; nitrogen monoxide no; semiconductor gas sensor; room temperature; visible light activation
• Online Access: https://www.mdpi.com/2079-4991/10/1/70

Nitric oxide (NO) is one of the main environmental pollutants and one of the biomarkers noninvasive diagnosis of respiratory diseases. Organic-inorganic hybrids based on heterocyclic Ru (II) complex and nanocrystalline semiconductor oxides SnO₂ and In₂O₃ were studied as sensitive materials for NO detection at room temperature under periodic blue light (λ_max = 470 nm) illumination. The semiconductor matrixes were obtained by chemical precipitation with subsequent thermal annealing and characterized by XRD, Raman spectroscopy, and single-point BET methods. The heterocyclic Ru (II) complex was synthesized for the first time and characterized by ¹H NMR, ¹³C NMR, MALDI-TOF mass spectrometry and elemental analysis. The HOMO and LUMO energies of the Ru (II) complex are calculated from cyclic voltammetry data. The thermal stability of hybrids was investigated by thermogravimetric analysis (TGA)-MS analysis. The optical properties of Ru (II) complex, nanocrystalline oxides and hybrids were studied by UV-Vis spectroscopy in transmission and diffuse reflectance modes. DRIFT spectroscopy was performed to investigate the interaction between NO and the surface of the synthesized materials. Sensor measurements demonstrate that hybrid materials are able to detect NO at room temperature in the concentration range of 0.25−4.0 ppm with the detection limit of 69−88 ppb.