Influence of Room-Temperature Ionic Liquids on the Electrosynthesis of CuBDC Type Metal-Organic Frameworks: Crystallite Size and Productivity

The influence of imidazolium- and ammonium-based room-temperature ionic liquids (RTILs) i.e., [bmim][BF₄], [bmim][DCA], and MTBS, respectively, as electrolytes on the crystallite size and productivity of CuBDC (BDC=1,4-benzenedicarboxylate) type metal-organic frameworks (MOFs) by electrosynthesis method via anodic dissolution was investigated. CuBDC was characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and nitrogen physisorption. The crystallite size and productivity of CuBDC using [bmim][BF₄], [bmim][DCA], MTBS as electrolytes were 24.7 nm, 22.1 nm, 20.5 nm, and 236 mg/h, 69 mg/h, 291 mg/h, respectively. Bulkier structure of ammonium-based RTILs resulted CuBDC with a smaller crystallite size and higher productivity compared to imidazolium-based RTILs

Pengaruh Perbandingan Massa Silikon/Silika terhadap Karbon pada Kinerja Anode Baterai Litium Ion dari Sekam Padi

This study aims to investigate the possible utilization of silica (SiO2) and silicon (Si) derived from rice husks as anode materials in lithium-ion batteries (LIBs). SiO2 and Si have impressive theoretical capacities of 1965 and 4200 mAh/g, respectively. However, their direct use as LIBs anodes faces challenges such as substantial volume changes during battery charging and discharging, as well as low electrical conductivity. Consequently, a common approach is to create nanostructures of SiO2 and Si, such as nanoparticles, nanowires, and nanotubes, and combine them with conductive matrices like carbon-based materials. In this study, the Si/SiO2/C composite was synthesized from rice husks, taking into account the mass ratio of Si/SiO2 to C. The process involved first separating SiO2 and C from rice husks and then synthesizing the composite using the ball mill method and activated molten salt aluminothermic reduction (AlCl3/NaCl). X-ray Diffraction (XRD) analysis confirmed the successful synthesis of the composite, as indicated by characteristic peaks of the constituent compounds. Scanning Electron Microscope (SEM) imaging showed non-uniform morphology with varying particle sizes. Tests results demonstrated that the Si/SiO2/C composite with a 3:1 ratio exhibited the most promising performance as a LIB anode, maintaining a high capacity of 280.48 mAh/g with a Coulombic Efficiency (CE) of 99% after 50 testing cycles. These findings suggest that silica and silicon compounds derived from rice husks hold great potential as efficient and durable anode materials for LIBs applications

Penentuan Resistivitas Tak-Terkompensasi Cairan Ion Berbasis Imidazol dengan Metode EIS: Pengaruh Panjang Alkil dan Perbedaan Anion

Ionic liquids have interesting properties because they have several advantages compared to conventional organic solvents, such as high thermal stability, high viscosity, good solvent properties, non-flammable, and non-volatile. In electrochemistry, ionic liquids can be used as solvents without the addition of electrolytes. However, ionic liquids still have resistivity properties (uncompensated resistance), thus ohmic drop measurements are needed for a potential correction. Imidazole-based ionic liquids, which are known for their high conductivity and commonly used as a solvent, have been measured of their resistivity as a function of temperature, and type of their cations/anions. Electrochemical Impedance Spectroscopy (EIS) method was chosen to measure the resistivity of ionic liquids and Bode plot was generated for the analysis of the results. The measured resistivities of ionic liquids are in the range of 420 to 1500 ohm. It is concluded that the resistivity of the imidazole-based ionic liquid is influenced by the size of their constituent ions, the viscosity, and the resistance is decreased with increasing temperature

Microwave-Assisted Synthesis of DUT-52 and Investigation of Its Photoluminescent Properties

A zirconium metal-organic framework (MOF) of DUT-52 (DUT: Dresden University of Technology) was synthesized herein by reacting zirconium tetrachloride (ZrCl4) and 2,6-naphthalenedicarboxylic acid (H2NDC) in DMF under microwave heating at 115 oC for 25 min. This synthetic procedure was more efficient than a solvothermal method, by which a long thermal exposure (24 h) of 100-150 oC was required to produce the same MOF. The MOF has a thermal stability of 560 °C, prior to partial loss of interconnected 2,6-naphthalenedicarboxylate (NDC) linkers at some structure building units (SBU). Crystallinity of this DUT-52 was ca. 77 %, which was the same as one synthesized solvothermally.  Diffuse Reflectance UV-Vis spectra revealed an absorption at λex of 287 nm, which was equivalent to a bandgap energy of 4.32 eV.  Electron excitations of this DUT-52 at 275 and 300 nm gave emission wavelength of 433 nm (a purple region),  indicating a prospective use of DUT-52 as a photoluminescent material. Copyright © 2019 BCREC Group. All rights reserve

EFFECT OF CRYSTALLINITY TO OVERPOTENTIAL ON Ni₃Fe ALLOY AS ELECTROCATALYST IN HYDROGEN EVOLUTION REACTION

EFFECT OF CRYSTALLINITY TO OVERPOTENTIAL ON Ni3Fe ALLOY AS ELECTROCATALYST IN HYDROGEN EVOLUTION REACTION. Ni-Fe alloys can be used as electrocatalyst for the hydrogen evolution reaction (HER) in an alkaline solution. HER consumed highly energy and overpotential driven. The overpotential value corresponding to the electron transfer in reaction can be affected either by metal combination or alloy as a cathode. Ni₃Fe  alloy had been successfully synthesized by the electrodeposition method using direct-current (DC) on a 304 L type stainless steel substrate. The modified Watts bath deposition was used NiCl2·6H2O and FeCl3·6H2O as precursors of the alloy. The optimum conditions of the reaction were obtained at pH of the solution is 2.20±0.02 with 25 mA/cm² current density at 55 °C for 160 minutes. Ni₃Fe alloy was characterized by Powder X-ray Diffraction (PXRD), Energy-Dispersive X-ray Spectroscopy (EDX), and Scanning Electron Microscopy (SEM). The electrocatalytic property of Ni3Fe alloy was electrochemically measured in 1 M KOH solution by polarization method using a Tafel plot with a scanning rate of 1 mV/s. As a result, the mass ratio of Ni²+ /Fe³+ in bath deposition influenced the electrocatalytic property of Ni₃Fe alloy. Ni₃Fe alloy with a higher crystallinity lowered the overpotential value of HER up to 67% compared to Ni metal

Facile one-pot microwave-assisted synthesis of rod-like and hexagonal plate-like AgNP@Ni-BTC composites for a potential salivary glucose sensor

Diabetes is a serious disease with a huge number of patients worldwide. Glucose levels in people with diabetes are above 6.6 mM in blood samples and 200 μM in saliva samples. Metal-organic frameworks (MOFs) have outstanding properties for glucose sensors, such as a large surface area and being rich in active sites. In this research, a silver nanoparticle@Ni-BTC (AgNP@Ni-BTC) composite was synthesized through one-pot synthesis using a microwave at 130 °C for 1 hour at 200 W. The results showed that the 4%AgNP@Ni-BTC-modified carbon paste electrode obtained better sensor performance than Ni-BTC with a limit of detection (LoD) of 14.73 μM, a sensitivity of 6584.89 μA mM−1 cm−2, and a linear range of 10–1250 μM. The 4%AgNP@Ni-BTC-modified carbon paste electrode also had better stability than Ni-BTC and had good reproducibility. Glucose detection tests on salivary samples showed that the 4%AgNP@Ni-BTC-modified carbon paste electrode could be used to measure glucose levels in salivary samples

Effect of Crystallinity to Overpotential on Ni₃fe Alloy as Electrocatalyst in Hydrogen Evolution Reaction

EFFECT OF CRYSTALLINITY TO OVERPOTENTIAL ON Ni3Fe ALLOY AS ELECTROCATALYST IN HYDROGEN EVOLUTION REACTION. Ni-Fe alloys can be used as electrocatalyst for the hydrogen evolution reaction (HER) in an alkaline solution. HER consumed highly energy and overpotential driven. The overpotential value corresponding to the electron transfer in reaction can be affected either by metal combination or alloy as a cathode. Ni₃Fe alloy had been successfully synthesized by the electrodeposition method using direct-current (DC) on a 304 L type stainless steel substrate. The modified Watts bath deposition was used NiCl2·6H2O and FeCl3·6H2O as precursors of the alloy. The optimum conditions of the reaction were obtained at pH of the solution is 2.20±0.02 with 25 mA/cm² current density at 55 °C for 160 minutes. Ni₃Fe alloy was characterized by Powder X-ray Diffraction (PXRD), Energy-Dispersive X-ray Spectroscopy (EDX), and Scanning Electron Microscopy (SEM). The electrocatalytic property of Ni3Fe alloy was electrochemically measured in 1 M KOH solution by polarization method using a Tafel plot with a scanning rate of 1 mV/s. As a result, the mass ratio of Ni²+ /Fe³+ in bath deposition influenced the electrocatalytic property of Ni₃Fe alloy. Ni₃Fe alloy with a higher crystallinity lowered the overpotential value of HER up to 67% compared to Ni metal

Influence of Room-Temperature Ionic Liquids on the Electrosynthesis of CuBDC Type Metal-Organic Frameworks: Crystallite Size and Productivity

The influence of imidazolium- and ammonium-based room-temperature ionic liquids (RTILs) i.e., [bmim][BF₄], [bmim][DCA], and MTBS, respectively, as electrolytes on the crystallite size and productivity of CuBDC (BDC=1,4-benzenedicarboxylate) type metal-organic frameworks (MOFs) by electrosynthesis method via anodic dissolution was investigated. CuBDC was characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and nitrogen physisorption. The crystallite size and productivity of CuBDC using [bmim][BF₄], [bmim][DCA], MTBS as electrolytes were 24.7 nm, 22.1 nm, 20.5 nm, and 236 mg/h, 69 mg/h, 291 mg/h, respectively. Bulkier structure of ammonium-based RTILs resulted CuBDC with a smaller crystallite size and higher productivity compared to imidazolium-based RTILs