Graphene is a thin layer carbon material that has become a hot topic of research during this decade due to its excellent thermal conductivity, mechanical strength, current density, electron mobility and surface area. These extraordinary properties make graphene to be developed and applied in various fields. On this basis, researchers are interested to find out the methods to produce high quality graphene for industrial use. Various methods have been developed and reported to produce graphene. This paper was designed to summarize the development of graphene synthesis methods and the properties of graphene products that were obtained. The application of graphene in the various fields of environment, energy, biomedical, sensors, bio-sensors, and heat-sink was also summarized in this paper. In addition, the history, challenges, and prospects of graphene production for research and industrial purposes were also discussed.

Gelatin has been widely used as an additive in pharmaceutical, cosmetic, and food industry. The similar physical appearance between bovine and porcine gelatin causes an issue for some communities like a Muslim due to awareness of halal food. A Muslim community consider porcine gelatin is non-halal material which must be avoided. So there is a demand to distinguish and labeling the origin source of the gelatin in any products. In turn, it lead to development of  a method to identify the source of gelatin. In this study, performance of a modified Quartz Crystal Microbalance (QCM) sensor to identify halal gelatin has been investigated. A QCM sensor was modified by depositing polyaniline/nickel compound on the surface of gold electrode QCM carried out by Layer by Layer (LbL) deposition technique. Bovine and porcine gelatin were measured in demineralized water at pH 9. This modified QCM sensor shows good frequency response to distinguish bovine and porcine gelatin. The measurements gave a negative frequency shifts for bovine gelatin and a positive frequency shifts for porcine gelatin. The modified QCM sensor also worked well in the real sample. This indicates that a modified QCM sensor is very useful and effective technique to distinguish bovine gelatin (halal) from porcine gelatin (non-halal).

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Modification of gold electrode using single-walled carbon nanotubes (SWCNTs) has been done. The synthesis of SWCNTs on the gold electrode surfaces was carried out using chemical vapor deposition (CVD) method. The performance of the electrodes as a sensor was characterized using dopamine (DA) solution at pH 4 by cyclic voltammetry. A change in electrode capacitance was found before and after DA detection. The detection limit and sensitivity of the electrodes are 0.79 μM and 3.414 μA mm −2 μM −1 , respectively. No interference signal was found from ascorbic acid (AA) during DA measurement. DA is a chemical compound that belongs to catecholamine group and have important roles in the central nervous.1 It is found in human body and commonly located at the hypothalamus.2 Low level of DA on the human body can cause some disorders, e.g. Alzheimer, schizophrenia, and Parkinson.3-5 Therefore, DA detection is important to find out the amount of DA inside the human body.Electrochemistry is an analytical method that had been applied as a biosensor.6 This method is commonly used because it is relatively fast, simple and low-cost. 7 Biosensors selectivity and sensitivity improvements can be conducted by modifying the electrodes using a specific material.8 Most of the modified electrodes are platinum, silver and gold. 8 The modified electrodes have been reported as a dopamine (DA) biosensor, i.e. gold nanoparticles electrode, 1 calixarene modified GCE, 5 nanoporous Au-Ag alloy electrodes, 3 and carbon nanomaterial electrodes. 4 Several scientists already used carbon nanotubes (CNTs) with various materials combinations to detect DA. [9][10][11][12] In this research, we used single-walled carbon nanotubes (SWCNTs) modified gold electrode as working electrodes for DA detection. SWCNTs is one of the most preferred materials that is used as a biosensor because of its dimensional character. 13 This material was made in our laboratory by a CVD method which is relatively different with available catalyst in the Market.14 The type of the catalyst used in the SWCNTs synthesis influenced the activity performance of the catalyst itself. 15 In our previous research, we modified gold electrodes using gold nanoparticles that have detection limit of 2 μM.1 The performance of the SWCNTs modified gold electrode in this research will be compared with the previous work. ExperimentalSynthesis of single-walled carbon nanotubes (SWCNTs).-Gold electrodes were modified with SWCNTs by CVD method as from our previous work.14, 16 The results obtained from Field-emission scanning microscopy (FE-SEM) and Transmission electron microscopy (TEM) indicated that SWCNTs were bundled with each other, resulting in tubes with diameters of 5-20 nm. The SWCNTs intensity ratio obtained from Raman Spectroscopy at G-band and D-band at ca.1590 cm −1 and 1350 cm −1 respectively, was ca. 20 when a wavelength of 514,5 nm was used. The D-band was very weak, which indicated that * Electrochemical Society Member.z E-mail: fredy@chem.its.ac.id the SWCNTs contained high level cry...

The extract of honeycomb waste was studied as a corrosion inhibitor on 304 stainless steel in H2SO4 solutions. The honeycomb waste was obtained from beekeeping at Lawang-Malang, East Java, Indonesia. Electrochemical and scanning electron microscopy methods were used to investigate the performance of the corrosion inhibition process. The inhibition efficiency of the inhibitor (2000 mg/L) reached 97.29% in 0.5 M H2SO4 and decreased with the acid concentration. Kinetic parameters were calculated to explain the effect of acid concentration on the inhibition process. The study on the adsorption behavior of the extracts followed the Frumkin isotherm model. The adsorption of the inhibitor on the 304 stainless steel surface was confirmed by the negative and lower values of Gibbs free energy. The obtained scanning electron microscopy (SEM) images were confirmed by comparing the surface of the specimens with and without inhibitor after corroding for one week. The results indicated that the extract acted as a good inhibitor for 304 stainless steel in acid corrosion.