With the growing concern over the adverse effects of environmental pollution on human health, the combination of environmentally friendly and nontoxic biomaterials with metal oxide semiconductor materials for electronic devices has emerged as a prominent trend in current research. In this study, we utilized 150 mg apple biotemplates to assist in the hydrothermal synthesis of ZnO nanospheres. It successfully achieved high sensitivity for detecting 35 and 350 ppb NO₂ at room temperature, with responses of 13.74 and 132.44%, respectively. Simultaneously, the 5-cycle repeatability and multiple-gas selectivity exhibited significant improvements. The ZnO nanospheres demonstrated enhanced sensing performance compared to pure ZnO nanorods, which is attributed to the following mechanisms: reason I, the modified surface morphology increasing the surface-to-volume ratio; reason II, an increase in oxygen vacancies, leading to reduced crystallinity and a higher electron concentration; reason III, incorporation of carbon elements on the nanostructure surface to increase active sites. The novel gas sensor assisted by the apple pectin biotemplate offers a promising solution for NO₂ gas detection, featuring low operating temperatures, low concentrations, and high response sensitivity.

Novel gas sensor devices, based on biomaterial apple pectin film (APN) doped with NiO, were fabricated for the first time using a solution processing technique. The device was then annealed in a microwave chamber. The structural, elemental, and surface morphology of the device was investigated, using TEM, XPS, and AFM, respectively. The as-fabricated film sensor possessed a superior sensing performance regarding ethanol gas, compared to the pure apple pectin film sensor. The response of the device was recorded at a maximum efficiency of 161. For a 10 ppm concentration of ethanol gas at an operational temperature of 250 °C, the response time was 1.379 s. Nevertheless, the sensing mechanism for the sensor device is also described thoroughly.

In this study, spherical-like ZnO UV photodetectors based on the facile hydrothermal method, induced different concentrations of apple pectin as the biotemplate. Apple pectin can react with zinc particles and change the pH value, which plays an essential role in modifying surface morphology. Moreover, apple pectin extracted from apple peels as carbon and nitrogen sources can also be used to improve absorption properties and increase depletion region to reduce dark current. The best results were obtained when 150 mg of apple pectin was used, showing a high UV-to-dark current ratio and fast response and recovery times. The UV-to-dark current ratio is as high as 80106.1, which is better than that of pure ZnO (4.47). Fast response and recovery times are also swift. The physical properties were evaluated using various techniques, including scanning electron microscopy, photoluminescence (PL), X-ray diffraction, and energy-dispersive X-ray (EDX), respectively. The results of this study suggest that the use of apple pectin in the hydrothermal synthesis of ZnO may offer a promising approach for modifying ZnO materials.

In this study, we synthesized microstructures using a straightforward hydrothermal method and extensively characterized them using various analytical techniques. Such as X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray photoelectron spectrum (XPS) have been used to verify the crystal phase, morphology and composition Following this characterization, we assessed the NO ₂ sensing performance of the fabricated sensors. Surprisingly, at a low operating temperature of 110 °C with a response of 1736.03%, the GA/ZnO microstructures exhibited remarkable selectivity, displaying robust repeatability (12 cycles) and stability (22 days) in their response. Furthermore, our findings revealed that introducing Gum Arabic (GA) as a biocompatible substrate significantly increased surface oxygen vacancies, acting as additional adsorption sites for NO ₂ . Consequently, this improvement enhanced gas detection performance and demonstrated exceptional selectivity in practical applications. Upon comparison with other literature, we observed the maximum response value at a low concentration in the ppb level.