In this work, a novel method for electrode modification based on inkjet-printing of electrochemically synthesized graphene-PEDOT:PSS (GP-PEDOT:PSS) nanocomposite is reported for the first time. GP-PEDOT:PSS dispersed solution is prepared for use as an ink by one-step electrolytic exfoliation from a graphite electrode. GP-PEDOT:PSS layers are then printed on screen printed carbon electrodes (SPCEs) by a commercial inkjet material printer (Dimatrix Inc.) and their electrochemical behaviors towards three common electroactive analytes, including hydrogen peroxide (H₂O₂), nicotinamide adenine dinucleotide (NAD⁺/NADH) and ferri/ferro cyanide (Fe(CN)₆ ^{3 −/4−}) redox couples, are characterized. It is found that the oxidation signals for H₂O₂, NADH and K₂Fe(CN)₆ of PEDOT:PSS modified and GP-PEDOT:PSS modified SPCEs are ∼2–4 and ∼3–13 times higher than those of unmodified SPCE, respectively. In addition, excellent analytical features with relatively wide dynamic ranges, high sensitivities and low detection limits have been achieved. Therefore, the inkjet-printed GP-PEDOT:PSS electrode is a promising candidate for advanced electrochemical sensing applications.

In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT)-doped tungsten oxide (WO₃) thin films by means of the powder mixing and electron beam (E-beam) evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO₃ thin film exhibits high sensitivity and selectivity to hydrogen. Thus, MWCNT doping based on E-beam co-evaporation was shown to be an effective means of preparing hydrogen gas sensors with enhanced sensing and reduced operating temperatures. Creation of nanochannels and formation of p-n heterojunctions were proposed as the sensing mechanism underlying the enhanced hydrogen sensitivity of this hybridized gas sensor. To our best knowledge, this is the first report on a MWCNT-doped WO₃ hydrogen sensor prepared by the E-beam method.

In this article, we present a new, facile and efficient electrochemical method for the production of a stable aqueous dispersion of a graphene–metal phthalocyanine hybrid material. The material has been prepared by electrolytic exfoliation of graphite in an electrolyte containing copper phthalocyanine-3,4′,4′′,4′′′-tetrasulfonic acid tetrasodium salt (TSCuPc). Single- and few-layer graphene sheets, decorated with metal phthalocyanine molecules, are generated during the electrolysis and stably dispersed in the electrolyte with no further chemical treatment. Scanning electron/atomic force microscopic characterization shows that the TSCuPc–graphene hybrid structure has a sharp-edged particle morphology with thicknesses ranging from 2 nm to 6 nm, corresponding to 1 to 6 graphene-stacked layers and largely varied lateral dimensions from a few tens to several hundreds of nanometers. In addition, Raman/FTIR/UV-Vis spectra and X-ray diffraction reveal characteristic peaks that suggest that the TSCuPc–graphene hybrid is formed by non-covalent π–π interactions between graphene sheets and metal phthalocyanine and indicate a high quality graphene hybrid structure that can potentially be used in practical applications.

In this research work, a non-enzymatic amperometric sensor for the determination of glucose was designed based on carbon nanodots (C-dots) and copper oxide (CuO) nanocomposites (CuO-C-dots). The CuO-C-dots nanocomposites were modified on the surface of a screen-printed carbon electrode (SPCE) to increase the sensitivity and selectivity of the glucose sensor. The as-synthesized materials were further analyzed for physico-chemical properties through characterization tools such as transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR); and their electrochemical performance was also studied. The SPCE modified with CuO-C-dots possess desirable electrocatalytic properties for glucose oxidation in alkaline solutions. Moreover, the proposed sensing platform exhibited a linear range of 0.5 to 2 and 2 to 5 mM for glucose detection with high sensitivity (110 and 63.3 µA mM⁻¹cm⁻²), and good selectivity and stability; and could potentially serve as an effective alternative method of glucose detection.

In this work, an innovative, low cost and effective screen printed graphene–carbon paste electrode (SPGE) for advanced electrochemical sensing is reported. The SPGE is prepared by mixing electrolytically exfoliated graphene powder with carbon paste and is then screen printed on polyvinyl chloride substrate. The electrochemical device comprises three electrodes including SPGEs as the working and counter electrodes and silver/silver chloride paste as the reference electrode. Material characterization by electron microscopy and Raman spectroscopy confirms that the size of the multilayer graphene is in the range of 250–400 nm and that the carbon paste matrix is composed of 20–30 nm carbon nanoparticles. The electrochemical performances of the SPGE towards three of the most common electroactive analytes including hydrogen peroxide (H₂O₂), nicotinamide adenine dinucleotide (NAD⁺/NADH) and ferri/ferro cyanide (Fe(CN)₆ ^3−/4−) redox couples are characterized. It is found that graphene inclusion considerably enhances electrochemical responses towards the analytes, with 10% being an optimum graphene concentration. The oxidation signals for H₂O₂, NADH and K₄Fe(CN)₆ of the SPGE with the optimal graphene concentration are found to be ∼2.0, ∼1.8 and ∼1.7 times higher than those of a screen printed carbon paste electrode, respectively. In addition, excellent analytical features with relatively wide dynamic ranges, high sensitivities, low detection limits and high reproducibility are achieved. Therefore, the SPGE is a promising candidate for low-cost and advanced electrochemical sensing applications.