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The high concentration of nitrogen dioxide (NO2) gets it one of the most popular and harmful air pollutants. This work examines the NO2 gas sensing properties of palladium-doped zinc oxide (Pd-ZnO) nanorods. The Pd-ZnO nanorods were synthesized by chemical hydrothermal method with different Pd doping concentrations (0–1 wt%). The Pd-ZnO nanorods were characterized by XRD, FESEM, and XPS for their structural and morphological properties, respectively. The ZnO nanostructures show hexagonal structures, and XRD and XPS results confirmed the doping of Pd on ZnO nanostructures. The Pd (1 wt%)-ZnO nanorods-based sensor shows high response of 22.1 with response/recovery time of 67/118 s toward 100 ppm NO2, while it exhibits a response of 7 with response/recovery times of 80/145 s for 1 ppm NO2, at 200 °C. The sensor is observed very selective for NO2 compared to other gases like carbon monoxide (CO), ammonia (NH3), and hydrogen (H2). The sensor has strong stability for a longer time (35 days) in a dry and humid (RH 60%) environment. The mechanism of gas sensors is further explained by the Crowell-Sze model in Finite-Difference Time-Domain (FDTD) simulation using COMSOL Multiphysics using drift Diffusion-Poisson equations to simulate the electric potential distribution in the nanorods during the gas sensing. [ABSTRACT FROM AUTHOR]

Today, monitoring and classification of hydrogen gas by metal oxide-based sensors are widely studying to improve their selectivity and stability. In present work, hydrogen sensing properties of magnetron sputtered deposited pure SnO2 thin films have been studied. The pure SnO2 thin film was deposited on glass substrate and as-deposited film was annealed at 450 °C for 6 hrs. The annealed SnO2 thin film has crystalline tetragonal structure, granular surface morphology and non-stoichiometry elemental composition of tin and oxygen vacancies. A higher gas sensing response is obtained for annealed SnO2 thin film as compare to as-deposited SnO2 thin film.A limit of detection (LOD) ~175 ppb is estimated for annealed SnO2 thin filmbased sensor. This sensor exhibits fast response and recovery time of 42 s/52 s for 50 and 500 ppm hydrogen gas, respectively. The sensor is found highly selective towards H2 gas in compare to different gases such as methane, carbon monoxide and nitrogen dioxide. [ABSTRACT FROM AUTHOR]

A new thiosemicarbazone derivative, benzophenone N(4)-methyl-N(4)-phenyl thiosemicarbazone (BMPT) is synthesized using benzophenone and N(4)-methyl-N(4)- phenylthiosemicarbazide as precursors. Synthesized ligand is characterized by Fourier Transform Infrared spectra (FTIR) and FT-Raman spectra. Complete quantitative assignments of vibrational modes are presented in terms of potential energy distribution (PED) using quantum chemical calculations using the density functional theory (DFT) approach. Natural bond orbital (NBO) and molecular electrostatic potential (MEP) surface analysis are used to estimate the correlation between molecular structure and biological activity at the electronic level. Hirshfeld surface analysis is used to interpret the intermolecular interactions and also to provide information about the percentage contribution of various intermolecular contacts in the crystal structure. Besides the above, molecular docking studies of BMPT ligand with 3RGF and 3EWD proteins are also performed to confirm the ability of BMPT ligand as an active pharmaceutical ingredient (API) of potential anticancer and antimalarial drugs. [ABSTRACT FROM AUTHOR]

Detecting and identifying hydrogen gas leakage before a potential disaster is a critical safety concern. To address this issue, a low-cost and simple-design sensor is required with high response and fast sensing time, capable of detecting hydrogen gas even at low concentrations of 5–500 ppm. This study investigates the use of magnetron-sputtered SnO2 thin films with palladium as a catalytic layer to achieve better sensing output. The developed Pd-caped SnO2 thin film sensors showed increased sensitivity with increasing thickness, up to 246.1 nm at an operating temperature of 250 °C. The sensor with a thickness of 246.1 nm exhibited excellent selectivity for H2 gas, even in humid conditions, and was able to distinguish it from other gases such as CO, NH3, and NO2. The sensor demonstrated high response (99%) with a response/recovery time of 58 s/35 s for (5–500 ppm) hydrogen gas. The sensor showed linear response to H2 gas concentration variation (5–500 ppm) at 250 °C. The sensor was found to be mechanically stable even after 60 days in a high-humidity environment. The LOD of sensor was 151.6 ppb, making it a suitable candidate for applied sensing applications. The Pd-caped SnO2 thin film sensor with thickness of ~245 nm could potentially improve the safety of hydrogen gas handling. [ABSTRACT FROM AUTHOR]