Carbon, especially graphene quantum dots (GQDs) based electronics have become an attractive technology in recent years. The controlled modification of the electrical and optoelectronic properties of GQDs by physical/chemical processes or synthetic methods may lead to new applications. Gadolinium‐doped polyethyleneimine (PEI) functionalized and nitrogen‐doped graphene quantum dots (GdNPs‐PEI@N‐GQDs) are synthesized by a hydrothermal method to determine how doping carbon‐based materials with Gd alters the electrical properties of the structure. The electrical properties of the GdNPs/PEI@N‐GQDs nanocomposite‐based diode are investigated using the current–voltage (I–V) technique and the capacitance and conductance voltage (C–V & G/ω–V) technique at 300 K in the frequency range of 0.5 to 500 kHz at ± 5 V. The rectification ratio (RR) is found to be 14 at a voltage of ±5 V. The rectifying behavior of the diode changes to an ohmic behavior after doping with Gd, compared to the Gd‐free PEI@N‐GQDs sample (2.8 × 104 at ±5 V). The results are expected to have an impact on the understanding of carbon‐based electronics technology.

In this study, the adsorption of NH3 gas on a bentonite from Ünye (Turkey) in its natural state and after acid treatments, was investigated experimentally at 298 K and up to 100 kPa. Bentonite was treated with HCl solutions of various concentrations (0.5–2.5 M) at 75°C for 4 h. X-ray diffraction (XRD), X-ray fluorescence (XRF), N2 adsorption and thermogravimetric/differential thermal analysis (TG/DTA) were used to characterize the bentonite before and after acid treatment. The quantitative XRD analysis demonstrated that the bentonite sample was composed predominantly of smectite (75%), with abundant feldspar (20%) and minor opal-CT, analcime and quartz (5%). Increasing gas adsorption values of acid-treated bentonites were analysed depending on the structural changes of the clay. The NH3-adsorption capacities of the bentonite samples (3.801–5.068 mmol g–1) were also compared with previously studied clay-based materials (0.828–4.000 mmol g–1) in terms of their textural and structural differences.