In this article, we present the performance of Copper (Cu)/Graphene Nano Sheets (GNS) and C—π (Graphite, GNS, and Nitrogen-doped Graphene Nano Sheets (N—GNS)) as a new battery electrode prototype. The objectives of this research are to develop a number of prototypes of the battery electrode, namely Cu/GNS//Electrolyte//C—π, and to evaluate their respective performances. The GNS, N—GNS, and primary battery electrode prototypes (Cu/GNS/Electrolyte/C—π) were synthesized by using a modified Hummers method; the N-doped sheet was obtained by doping nitrogen at room temperature and the impregnation or the composite techniques, respectively. Commercial primary battery electrodes were also used as a reference in this research. The Graphite, GNS, N—GNS, commercial primary batteries electrode, and battery electrode prototypes were analyzed using an XRD, SEM-EDX, and electrical multimeter, respectively. The research data show that the Cu particles are well deposited on the GNS and N—GNS (XRD and SEM—EDX data). The presence of the Cu metal and electrolytes (NH₄Cl and MnO₂) materials can increase the electrical conductivities (335.6 S cm⁻¹) and power density versus the energy density (4640.47 W kg⁻¹ and 2557.55 Wh kg⁻¹) of the Cu/GNS//Electrolyte//N—GNS compared to the commercial battery (electrical conductivity (902.2 S cm⁻¹) and power density versus the energy density (76 W kg⁻¹ and 43.95 W kg⁻¹). Based on all of the research data, it may be concluded that Cu/GNS//Electrolyte//N—GNS can be used as a new battery electrode prototype with better performances and electrical activities.

Graphene was synthesized through a two-step pyrolysis method using waste candlenut (Aleurites moluccanus) shells as the precursor. Cerium (Ce)/graphene composites were prepared via an impregnation technique. The resulting graphene and Ce/graphene were characterized using various analytical methods, including Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Cyclic Voltammetry (CV), and Linear Sweep Voltammetry (LSV). The bio-carbon produced predominantly exhibited a graphene structure with flat carbon morphology and an interlayer distance of 0.33 nm. This structural information is supported by XRD data, which shows a broad and weak peak at 2θ = 26° corresponding to the C (002) plane, indicative of graphene presence. FTIR, XPS, and Raman spectroscopy further confirmed the presence of graphene through the detection of Csp2 aromatic bonds and the characteristic D, G, and 2D peaks. Notably, the performance of cerium can be enhanced by the incorporation of graphene, attributed to the large surface area and chemical interactions between Ce and graphene. Consequently, candlenut-derived graphene shows potential as a supportive material for modifying the properties of cerium, due to the current value of Ce/Graphene increase with presence of graphene, thereby opening avenues for various advanced applications, such as sustainable and high-performance energy storage systems.

Oil fuels derived from fossils are non-renewable, so over time, they will run out and have a negative impact on air pollution. To overcome this, there is a need for environmentally friendly alternative fuels from renewable sources such as biodiesel. This research used microwave heating with a CaO catalyst. NaOH-impregnated snail shells and active carbon support. This research aims to determine the effect of power on the conversion of candlenut seed oil into biodiesel using the NaOH/CaO/CA catalyst both in terms of compliance with the SNI 7182-2015 standard and analysis using GC-MS (Gas Chromatography-Mass Spectrometry). The synthesis of the NaOH/CaO/CA catalyst was carried out through wet impregnation and calcination at a temperature of 500°C and analyzed using gas sorption analysis (GSA). Then proceed to the transesterification process, where the power for microwave heating was varied to 300, 450, and 600 watts with a mole ratio of esterified oil and methanol, namely 1:10 for 3 minutes. The analysis results of the NaOH/CaO/CA catalyst using the GSA instrument have a surface area of 9.306 m²/g, pore volume of 0.033 cc/g, and pore diameter of 14.043 nm. Meanwhile, the results of the biodiesel analysis showed that the optimum biodiesel yield was 85.625% at 600 watts of power and had a kinematic density and viscosity that met the SNI 7182-2015 biodiesel standards. Analysis of biodiesel characteristics using GC-MS showed that the three most optimum biodiesel components were hexadecanoic acid, methyl ester (22.664%), 9,12-Octadedecadienoic acid (Z,Z)-, methyl ester (30.176%) and 9-Octadecenoic acid (Z)-, methyl ester (38.656%).

Graphene was synthesized through a two-step pyrolysis method using waste candlenut (Aleurites moluccanus) shells as the precursor. Cerium (Ce)/graphene composites were prepared via an impregnation technique. The resulting graphene and Ce/graphene were characterized using various analytical methods, including Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Thermo Gravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) spectroscopy, Cyclic Voltammetry (CV), and Linear Sweep Voltammetry (LSV). The bio-carbon produced predominantly exhibited a graphene structure with flat carbon morphology and an interlayer distance of 0.33 nm. This structural information is supported by XRD data, which shows a broad and weak peak at 2θ = 26° corresponding to the C (002) plane, indicative of graphene presence. FTIR, XPS, and Raman spectroscopy further confirmed the presence of graphene through the detection of Csp2 aromatic bonds and the characteristic D, G, and 2D peaks. Notably, the performance of cerium can be enhanced by the incorporation of graphene, attributed to the large surface area and chemical interactions between Ce and graphene. Consequently, candlenut-derived graphene shows potential as a supportive material for modifying the properties of cerium, thereby opening avenues for various advanced applications, such as sustainable and high-performance energy storage systems.

Silica oxide (SiO2) is a chemical compound that can be obtained from the extraction of volcanic ash from Mount Sinabung. Silicon dioxide has the properties of high porosity, high mechanical strength, high thermal stability, large pore surface area, stable surface in acidic media so that it can be applied in the chemical coating field.This research aims to measurement of performance natural silica from volcanic ash of mount Sinabung Indonesia as additives to the paint to inhibit corrosion rate in metal surface. The addition of silica additives to the paint was carried out by dispersing (0; 0.5; 0.75; and 1) g with 10 mL of paint with each composition carried out for 60 minutes. Iron plate in sandpaper with 1500 grid and polished with bludru cloth using autosol metal polish, then coated with paint and a combination of silica-paint through the dipcoating method. The corrosion test was carried out on a corrosive solution of HCl 15% (v/v) and NaCl 3.5% (w/v). The corrosion rate using HCl 15% (v/v) showed C (0,286) mpy, SC1 (0,123) mpy, SC2 (0,149) mpy, SC3 (0,120) mpy. While at 3.5% (w/v) NaCl, namely C (0,282) mpy, SC1 (0,120) mpy, SC2 (0,142) mpy, SC3 (0,098) mpy. Inhibitor efficiency for various variations of silica composition in corrosive HCl 15%(v/v) solution, e.g., SC1 (56,9%), SC2 (47,9%), and SC3 (58,04%). The inhibitor efficiency at various compositions of silica in NaCl 3.5% (w/v) are SC1 (57,44%), SC2 (49%) dan SC3 (65,24%).

Minyak jelantah merupakan sisa penggunaan bahan pangan, jika di konsumsi akan berbahaya bagi kesehatan. Kegiatan penelitian ini bertujuan untuk menjernihkan minyak jelantah menggunakan adsorben kitozenus yaitu dari limbah kulit durian. Metode penelitian secara laboratorium dengan metode fisika dan kimia. Hasil penelitian dilihat dari kualitas minyak jelantah setelah dijernihkan, yaitu dengan mengetahui bilangan iod dan perubahan warna. Proses pembuatan adsorben kitozenus menggunakan limbah kulit durian dengan diaktivasi KOH variasi konsentrasi 25%, 27% dan 30%. Yang sebelumnya adsorben melalui tahap karbonisasi dan setelahnya dilanjutkan dengan tahap kalsinasi pada suhu 900^oC. Adsorben kitozenus yang telah diperoleh kemudian dikarakterisasi dengan uji FTIR, SEM dan XRD. Hasil FTIR menunjukkan pada sampel adsorben Kitozenus dapat diketahui bahwa pada adsorben Kitozenus tampak pola yang hampir sama, diperoleh dengan variasi konsentrasi 30% puncak serapan pada bilangan gelombang 1033,85 cm^-1 yang merupakan vibrasi ulur asimetri dari gugus Si-O pada gugus siloksan (Si-O-Si). Variasi konsentrasi alkalis (KOH) 25%, 27%, dan 30% untuk aktivasi adsorben kitozenus menunjukkan semakin tinggi konsentrasi KOH (Alkalis) maka puncak serapan untuk Si-O pada adsorben semakin rendah. Hal ini menunjukkan bahwa semakin banyak silaka yang lepas dari adsorben (proses desilikalisasi). Hasil uji SEM menunjukkan dengan konsentrasi 30% lebih baik diantara semua variasi yaitu terlihat bahwa adsorben kitozenus memiliki rongga-rongga pori yang banyak dan tampak lebih jelas. Hasil bilangan iod yang diperoleh dari ketiga variasi yaitu 6,143 (25%), 5,314 (27%) dan 7,906 (30%). dan menunjukkan perubahan warna setelah penjernihan menggunakan adsorben kitozenus. Kata Kunci: adsorben, bilangan iod, minyak jelantah. Used cooking oil is the rest of the use of food, if consumed will be harmful to health. The purpose of this research is to purify used cooking oil using adsorbent kitozenus, which is from durian skin waste. Laboratory research methods using physical and chemical methods. The results of the study are seen from the quality of used cooking oil after being cleared, namely by knowing iodine numbers and color changes. The process of making kitozenus adsorbent uses durian skin waste by activating KOH variations in concentrations of 25%, 27% and 30%. The previous one was adsorbed through the carbonization stage and after that it was continued with the calcination stage at 900oC. The obtained kitozenus adsorbent was then characterized by FTIR, SEM and XRD tests. FTIR results showed that in the Kitozenus adsorbent sample it can be seen that on the Kitozenus adsorbent there was a similar pattern, obtained by varying the concentration of 30% absorption peak at wave number 1033.85 cm-1 which is the asymmetric stretching vibration of the Si-O group in the siloxane group ( Si-O-Si). The variations in alkaline concentration (KOH) of 25%, 27%, and 30% for activation of the kitozenus adsorbent showed that the higher the concentration of KOH (Alkalis), the higher the absorption peak for Si-O on the adsorbent. This shows that more and more silaka are separated from the adsorbent (desilicalization process). The SEM test results showed that with a concentration of 30% better among all variations, it was seen that the adsorbent kitozenus had many pores. The iodine numbers obtained from the three variations were 6,143 (25%), 5,314 (27%) and 7,906 (30%) and showed color changes after purification using the kitozenus adsorbent. Keywords: adsorbent, iodine number, used cooking oil