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The development of new and high-performing electrode materials for sensing applications is one of the most intriguing and challenging research fields. There are several ways to approach this matter, but the use of nanostructured surfaces is among the most promising and highest performing. Graphene and graphene-related materials have contributed to spreading nanoscience across several fields in which the combination of morphological and electronic properties exploit their outstanding electrochemical properties. In this review, we discuss the use of graphene and graphene-like materials to produce gas sensors, highlighting the most relevant and new advancements in the field, with a particular focus on the interaction between the gases and the materials. [ABSTRACT FROM AUTHOR]

In order to deepen the understanding of the role of transition metal oxides in electron transfer at the electrochemical interface, the performance of ZnxNi1−xFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) nanomaterials in electrochemical sensing is studied. Nanomaterials are synthesized by simple autocombustion synthesis procedure. Field‐emission scanning electron microscopy characterization shows that the particles have a size between 30 and 70 nm with an average crystallite size between 24 and 35 nm. The bandgap energies of the nanomaterials, as estimated by UV–vis experiments, are in the 2.32–2.56 eV range. The valence band maximum is evaluated using X‐ray photoelectron spectroscopy and the position of the conduction band minimum is estimated. The ZnFe2O4 sensor has the best performances: highest rate constant (13.1 ± 2.8 ms−1), lowest peak‐to‐peak separation (386 ± 2 mV), and highest sensitivity (37.75 ± 0.17 μA mM−1). Its limit of detection (7.94 ± 0.04 μM) is second best, and its sensitivity is more than twice the sensitivity of the bare sensor (16.7 ± 0.9 μA mM−1). Nanomaterials energy bands mapping with the experimental redox potentials is performed to predict the electron transfer at the electrochemical interface, and the importance of surface states/defects is highlighted in the electron transfer mechanism. [ABSTRACT FROM AUTHOR]

The growing usage and consumption of electronics‐integrated items into the daily routine has raised concerns on the disposal and proper recycling of these components. Here, a fully sustainable and green technology for the fabrication of different electronics on fruit‐waste derived paper substrate, is reported. The process relies on the carbonization of the topmost surface of different cellulose‐based substrates, derived from apple‐, kiwi‐, and grape‐based processes, by a CO2 laser. By optimizing the lasing parameters, electronic devices, such as capacitors, biosensors, and electrodes for food monitoring as well as heart and respiration activity analysis, are realized. Biocompatibility tests on fruit‐based cellulose reveal no shortcoming for on‐skin applications. The employment of such natural and plastic‐free substrate allows twofold strategies for electronics recycling. As a first approach, device dissolution is achieved at room temperature within 40 days, revealing transient behavior in natural solution and leaving no harmful residuals. Alternatively, the cellulose‐based electronics is reintroduced in nature, as possible support for plant seeding and growth or even soil amendment. These results demonstrate the realization of green, low‐cost and circular electronics, with possible applications in smart agriculture and the Internet‐of‐Thing, with no waste creation and zero or even positive impact on the ecosystem. [ABSTRACT FROM AUTHOR]

We present newly developed electrochemical sensors based on screen-printed carbon electrodes functionalized with HO-BiONO3, polyethylene glycol coated HO-BiONO3, and Bi5O7 NO3. The performance of these sensors has been studied by cyclic voltammetry experiments and compared in terms of the kinetic rate constant, the sensitivity, and the limit of detection. The polyethylene glycol coated HO-BiONO3 sensor was found with higher oxidation peak current, lower oxidation peak potential, and assured a faster paracetamol reaction due to a higher kinetic rate constant of 42.0 ± 9.8 ms−1. This sensor also possessed lesser peak-to-peak separation (ΔEp) of 243 ± 10 mV with a higher chance of reversible reaction compared to other developed sensors. The polyethylene glycol coated HO-BiONO3 sensor also registered a sensitivity of 43.50 ± 0.54 μA/mM with a relative standard deviation of 1.24 %, which is more than double compared to the bare screen-printed electrode with a limit of detection of 2.24 ± 0.03 μM (R2 =0.998, n = 3). HO-BiONO3 and Bi5O7 NO3 sensors also performed much better with slightly higher kinetic rate constant and higher sensitivity than the bare screen-printed electrode sensor. [ABSTRACT FROM AUTHOR]