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TiO2 Crystallization at Room Temperature and Preparation of Transparent Carbon Counter Electrode for Low-Cost Dye-Sensitized Solar Cells Syauqi, Muhammad Iqbal; Sanjaya, Afiten Rahmin; Madiabu, Mohammad Jihad; Khalil, Munawar; Gunlazuardi, Jarnuzi
Makara Journal of Science Vol. 27, No. 2
Publisher : UI Scholars Hub

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Abstract

We developed a low-cost dye-sensitized solar cell (DSSC) using TiO2 fabricated via rapid breakdown anodization (RBA) and ultrafast room-temperature crystallization (URTC). The prepared TiO2 was deposited on a self-made fluorine-doped tin oxide (FTO) conductive glass, and the FTO/TiO2 system was sensitized using curcumin dye. The DSSC was constructed by sandwiching the FTO/TiO2/curcumin electrode with an I−/I2 electrolyte and a transparent carbon counter electrode prepared using a liquid–liquid interface system. The characterization results showed that the TiO2 freshly prepared via URTC was transformed into an anatase crystalline phase, which exhibited a 3.10 eV band gap and a 10.08 nm average crystallite size, comparable to those of the TiO2 prepared via the conventional 450 °C annealing treatment (3.13 eV, 11.60 nm). The photocurrent activity of the URTC-prepared TiO2 under ultraviolet light (0.10 mA/cm2) was also comparable to that of the annealed TiO2 (0.12 mA/cm2). In addition, a transparent carbon electrode (FTO/Ct) was prepared successfully; it exhibited a ±58.26% transparency under visible light and comparable electrocatalytic activity to Pt-coated FTO. The DSSC based on FTO/TiO2-URTC/curcumin and FTO/Ct showed front and back illumination efficiencies of 0.47% and 0.26%, respectively. These results are only slightly lower than those of the conventional DSSC with FTO/annealed TiO2/curcumin//FTO/Pt, which exhibited front and back illumination efficiencies of 0.52% and 0.36%, respectively.
Carbon-coated nickel foam for hypochlorous acid sensor Sanjaya, Afiten Rahmin; Riyanto, Hanzhola Gusman; Rahmawati, Isnaini; Putri, Yulia Mariana Tesa Ayudia; Nurhalimah, Dede; Saepudin, Endang; Tesla, Yudistira; Krisnandi, Yuni Krisyuningsih
Environmental and Materials Vol. 1 No. 1: (June) 2023
Publisher : Institute for Advanced Science, Social, and Sustainable Future

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61511/eam.v1i1.2023.105

Abstract

The electrochemical detection method of hypochlorous acid (HOCl) using carbon foam electrodes have been successfully developed. The carbon foam was prepared from carbon-coated nickel foam which is synthesized using a hydrothermal-carbonization method. SEM characterization indicated that the optimum synthesis of carbon-coated nickel foam has been achieved on the 4th layer coating process with an expected spherical structure, while characterization using FTIR and Raman spectroscopy confirmed the formation of graphitic material with D band and G band characteristics. An electroactive surface area of ​​0.0236 cm2 was achieved. Cyclic voltammetry of HOCl in 0.1 M phosphate buffer solution pH 6.0 showed the best current response for HOCl reduction occurs at a potential of -0.3 V (vs. Ag/AgCl). Further detection of HOCl using amperometry technique in the concentration range of 2-200 μg/mL showed good linearity with sensitivity of 9.112 mA/µg/L and an estimated detection limit of 1.96 µg/mL. Good repetition is indicated by the RSD value of 2.499 % (n=5). This developed sensor also showed good selectivity in the presence of interference compounds, such as FeCl2 and CuSO4. Besides, the determination of HOCl in tap water has been successfully conducted and generated a comparable result with the UV-VIS method (3.30 µg/mL hypochlorite). The results indicated that the developed sensor is promising for the detection of HOCl in environmental applications.
Synthesis and characterization silica-MB@GO-NH2 particle as fluorescence-based chlorine sensor Fatah, Fadhlir Rahman Aufar Al; Rahmawati, Isnaini; Gunlazuardi, Jarnuzi; Sanjaya, Afiten Rahmin
Environmental and Materials Vol. 1 No. 2: (December) 2023
Publisher : Institute for Advanced Science, Social, and Sustainable Future

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61511/eam.v1i2.2023.399

Abstract

In this research, we developed a fluorescence-based sensor to determine the sodium hypochlorite concentration (NaOCl) in tap water and swimming pool water samples. The detection of NaOCl was conducted by measuring the luminescence response of analyte in the paper-based sensor modified Silica-MB@GO-NH2 material were synthesized using Hummer's and Stober's methods under UV Light irradiation. Additionally, the prepared material exposed a couple peak 2D and 2G at 2938 cm-1 and 3286 cm-1 with ID/IG ratio 0.98 using Raman characterization which appropriate with the presence of GO structure in the mixture. This result was validated by the appearance of several functional groups like Si-O-Si, NH, OH, and C-C at 1079, 1391, 1611, and 3457 cm-1, respectively. Moreover, the existence of Si-O-Si bond indicates that the silica-MB interaction was perfectly formed, which plays the main role to absorb ultraviolet light that is used as sensor probe. The morphology of particles depicted an aggregated formation of spherical structure with 288 nm particle size, indicating the existence of silica-coated methylene blue. In this work, the paper-based sensor modified Silica-MB@GO-NH2 can detect the NaOCl species with concentration range 10-150 µM (R2 = 0.9757), a detection limit at 2.60 µM and quantification limit at 7.88 µM. Furthermore, this developed sensor has stable measurement with recovery performance 3.65%-6.67% for tap water and 0.05%–0.14% for swimming pool water. This result indicates that the prepared sensor can be potentially applied to calculate the hypochlorite species in the aquatic environment.
Preparation of β-Ni (OH)2 Nanosheet–Modified Glassy Carbon for Pseudocapacitors Putra, Muhammad Buchari Setia; Aliyah, Aliyah; Sanjaya, Afiten Rahmin; Pramadewandaru, Respati Kevin; Chung, Hoeil; Ivandini, Tribidasari Anggraningrum
Makara Journal of Science Vol. 28, No. 2
Publisher : UI Scholars Hub

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Abstract

β-Nickel hydroxide (Ni(OH)2) nanosheet–modified glassy carbon for pseudocapacitors was successfully prepared. The nanosheets were synthesized via a conventional growth seeding method combined with hydrothermal treatment. Transmission electron microscopy (TEM) characterization indicated the hexagonal structure of the nanosheets of around 15 nm in size, and X-ray diffraction (XRD) pattern confirmed the β-phase lattice crystal. These nanosheets used to modify the glassy carbon surface, increased the electroactive surface area by around 15 times. Furthermore, electrochemical investigation of the modified glassy carbon revealed an excellent performance and a specific capacitance of 628.01 F g−1 at a 1 A g−1 current density. Moreover, an outstanding stability was demonstrated, with 89.9% retention of the capacitance observed after 3000 cycles at a 1 A g−1 current density.
Preliminary Molecular Study of Chloramphenicol Anchoring on Laccase Enzyme from Trametes hirsuta Riyanto, Hanzhola Gusman; Sanjaya, Afiten Rahmin
Makara Journal of Science Vol. 28, No. 3
Publisher : UI Scholars Hub

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Abstract

Antibiotics are one of emerging pollutants generally emitted from livestock production and the food industry to the environment. The presence of this pollutant could initiate the development of resistant bacteria that can be fatal to human health. The degradation of antibiotics using enzymes or microbe could be an alternative because the residue or intermediate product is less harmful than of the conventional method. This research aims to support a preliminary study of the degradation of antibiotics using enzyme through molecular docking via Molecular Operating Environment software and molecular dynamics (MD) study via CABSFLEX 2.0 and WebGro macromolecular simulations. The molecular docking of the laccase-chloramphenicol complex has low binding energies of approximately −8.1350 and −8.2290 kcal/mol for both rigid and flexible methods, respectively, indicating that the formation of the complex is advantegous. MD simulation further revealed a decrease in rigidity after the interaction with the ligand. Hydrogen bonding analysis indicated up to five hydrogen bonds in the complex, underscoring the robustness of the enzyme--ligand interaction. These results collectively contribute to our understanding of the efficacy of enzyme-mediated antibiotic degradation and emphasize the potential for this approach to mitigate environmental and health concerns associated with antibiotic pollution
Preliminary study of screen–printed gold electrode for H2O2 sensor based on electrochemiluminescence of luminol Syukur, Junjunan Muhammad; Sanjaya, Afiten Rahmin; Rahmawati, Isnaini; Ridwan, Muhammad
Environmental and Materials Vol. 3 No. 1: (June) 2025
Publisher : Institute for Advanced Science, Social, and Sustainable Future

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61511/eam.v3i1.2025.1656

Abstract

Background: Hydrogen peroxide (H2O2) is mostly used in the water and dairy industries for sterilization and preservation purposes. However, excessive H2O2 residues in milk and tap water pose a health risk. Therefore, accurate measurement of H2O2 residue is essential.  Methods: This study explores the potential of a screen–printed gold electrode (SPGE) as a sensor for H2O2 sensor using the electrogenerated chemiluminescence (ECL) method of luminol in the electrolyte of phosphate buffer solution (PBS) under alkaline condition (pH of 9). Findings: The detection of H2O2 was achieved a linear calibration equation of y = 0.0215[H2O2] + 0.2006 within a concentration range of 0.5 to 200 µM (R2 = 0.9998), demonstrating reliable ECL measurements.  Conclusion: The analytical performance evaluation of H2O2 sensor exhibited a low limit of detection (LOD) of 3.06 µM, a limit of quantification (LOQ) of 10.20 µM, and good measurement repeatability, with a relative standard deviation (%RSD) of 6.03%, which is below ⅔ of the Horwitz coefficient of variation (9.85%). Unmodified SPGE offers simplicity, ease of use, a stable surface, and good conductivity while maintaining excellent performance. Novelty/Originality of this article: The application of the ECL method on SPGE for H2O2 detection offers excellent analytical performance, making it a promising approach for monitoring H2O2 residues in the water and dairy industries, with a recovery from 83.83 to 106.01%.
An acetylcholinesterase-based biosensor of carbofuran using carbon foam electrode modified by graphene and gold particles Pramadewandaru, Respati Kevin; Triani, Sulis; Tesla, Yudhistira; Sanjaya, Afiten Rahmin
Environmental and Materials Vol. 3 No. 1: (June) 2025
Publisher : Institute for Advanced Science, Social, and Sustainable Future

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61511/eam.v3i1.2025.1963

Abstract

Background: This study introduces a novel acetylcholinesterase (AChE)-based biosensor for the sensitive and selective detection of carbofuran, a widely used carbamate pesticide known for its neurotoxicity. Methods: The biosensor employs a carbon foam (CF) electrode modified with graphene oxide and gold nanoparticles (CF/Graphene/Au), leveraging the synergistic properties of these materials to enhance electrochemical performance. Carbofuran detection is achieved through its inhibitory effect on AChE activity, monitored via cyclic voltammetry of thiocholine oxidation. Findings: Under optimal conditions at pH 7.4, the biosensor demonstrated a linear detection range of 25–125 μM, a detection limit of 8.08 μM, and a sensitivity of 0.3874 mA μM⁻¹ cm⁻². It also showed strong reproducibility with a relative standard deviation of 6.77%. When tested on real vegetable samples, the biosensor achieved recovery rates between 88.95% and 111.30%. Conclusion: Compared to existing biosensor technologies, the CF/Graphene/Au-based sensor offers a well-balanced performance in terms of sensitivity, detection range, and practical usability. It presents a viable and portable solution for monitoring pesticide residues in environmental samples. Novelty/Originality of this article:  This work presents a promising, portable solution for environmental monitoring of pesticide residues, integrating advanced nanomaterials and computational validation to improve detection accuracy and reliability.