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Nitrogen doping into graphene was carried out by heating Graphene Nano Sheets (GNS) in ammonia to produce N‐doped graphene (N−G). The N−G was used as a support material for Pt catalyst as well as a catalyst itself for half‐cell cathode reaction of hydrogen fuel cell (H2FC). It is found that the Oxygen Reduction Reaction (ORR) electro catalytic activity for N−G 900 (0.63 V versus RHE) is higher than GNS. It indicates that the incorporation of nitrogen in N−G may affect the ORR activities. XPS results exhibit the pyridinic N is the majority in N−G, where the pyridinic N refers to N atom bonds with two C atoms at the edges or defects of graphene. Interestingly, the Pt subnano‐clusters were formed on all of Pt/N−G catalysts with Pt particle size (0.7–1.0 nm). It clearly indicates that the doping of nitrogen significantly influence π–d hybridization in terms of electronic structures.

Magnetite (Fe3O4) nanostructures and their modifications with other materials show proper characteristics to be implemented as a sensing material. This paper provides a brief review of the application of the Fe3O4 nanostructures and their modifications as sensitive material for pollutant gas sensors. Several studies were highlighted to explain the past-to-present progress of materials development. Various synthesis procedures of the materials were also clearly explained. The application of pure Fe3O4 nanostructures and their modification as sensitive materials in gas sensor devices to detect toxic gases is the main section of this paper. Last, the future prospects section summarized the materials’ development and provided a suggestion for future development.

The objective of this study was to evaluate the effect of pyrolysis temperatures on composition and electrical conductivity of carbosil produced from rice husk, by conducting pyrolysis experiments at three different temperatures of 200; 400; and 700 °C. The structure of the samples was characterized using Fourier Transform Infrared (FTIR) Spectroscopy and X-Ray Diffraction (XRD). The microstructure and elemental composition were characterized using Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS), and the electrical conductivity was measured using four probe method. The FTIR analyses revealed the existence of Si-O-Si and Si-OH functional groups, but no functional groups associated with carbon, confirming the formation of carbosil. This formation of carbosil is also supported by the results of EDS analyses which show the presence of only three elements of C, O, and Si, respectively. The XRD results indicate that the carbosils are amorphous, suggesting that no transformation of carbon and silica into crystalline phase to the limit of the temperatures applied. The carbosil formation decreased with increasing of pyrolysis temperature. The microstructure of the carbosils indicates that the higher the temperature, the smaller the grain size of the samples. The values of electrical conductivity of the samples are in the range of 1.13 x 10-3 to 6.81 x 10-3/(Ω.m) with the application of 10 tones compression pressure, but the conductivities of the sample prepared at 200 °C were found to increase with increased compression pressure to six fold from 6.81 x 10-3 to 41.94 x 10-3/(Ω.m) by increasing compression pressure to 80 tones. Based on these conductivity values, the samples are considered as semiconductor, suggesting the potential use of the carbosil in semiconductor devices.

In this paper, we report about chemically interaction between Pt Subnano-Clusters on Graphene Nano Sheets (GNS). The aim of this research is to clarify the size effect of Pt clusters on Pt 1–7 wt.%/GNS. This research is an experimental laboratory research. GNS was synthesized by using modified Hummer’s method and 1–7 wt.% Pt/GNS were prepared with impregnation method. Then, they were analyzed with TG/DTA, XRD, TEM and XPS, respectively. The results show that Pt clusters are well deposited on GNS (TG/DTA and TEM data). Those data also are consistent with XRD data. The weak and broad peaks appear at 2θ = 39°, indicating Pt metal exists on GNS. The state of Pt is confirmed by using XPS. The appearance of Pt 4f. peaks proves that Pt metal is chemical interaction on GNS. The size of Pt clusters may affect the chemically properties of Pt/GNS catalysts.