Materials Science for Energy Technologies最新文献

In this study, we investigated the electrochemical catalysis potential of hybrid nanocomposites containing CdO, Co and ZnO nanocomposites, as opposed to Zn-O doped Co nanocomposites, have weaker Coulomb interactions due their ionic bonds. Because CdO and Co form a covalent bond, Co interacts more strongly with O than Zn. In order to reduce nanoparticle crystallinity, oxygen defects improve the interaction between −O and oxygen defects in the lattice. From SEM micrographs, it appears that CdO does not completely change under the influence of dopants. It can be seen from the SEM image that both materials have very tightly packed particles. The Co and CdO dopants in ZnO nanocomposites prevent them from absorbing a large range of visible wavelengths. It is more energy-dense for nanocomposites with 5.28 eV to compare to 5.14 eV nanocomposites. The fact that CdO matrix has a tuneable bandgap is evident since different types of dopants are used in its manufacture. There are at least three distinct absorption modes in Co nanocomposites doped with CdO, around 450, 498, and 676 cm⁻¹. In addition to its absorption from 450 cm⁻¹ and 498 cm⁻¹ vibrational modes, Co-O stretching absorption along the [1 0 1] plane has also been observed at 676 cm⁻¹. As a method of studying charge carriers, photoluminescence spectroscopy is usually used. This method can be used to analyze electron-hole pairs (e⁻/h⁺) formed by semiconducting particles. It is in the blue emission range between the luminescence band of 615 nm and the valence band of 635 nm. With increasing cobalt and zinc concentrations, CdO nanomaterials lose their remanent magnetization. CdO has been demonstrated to have significant coercive effects in both pure and additively incorporated solutions regardless of their anisotropic, morphological, porosity, and particle size distribution. Electrochemical impedance spectrum measurements were conducted between 100 kHz and 0.01 Hz. According to the Nyquist plot, purity CdO, CdO doped Co, and CdO doped ZnO nanocomposites show a high frequency resistance to charge transfer. Nanocomposites that contained CdO doped Co & ZnO were exposed to UV light for 120 min to remove the solution. The degradation of MO is virtually nonexistent when no photocatalyst is present, but with a photocatalyst, degradation can reach 92.56 %.

Hydrogen has attracted growing research interest due to its exceptionally high energy per mass content and being a clean energy carrier, unlike the widely used hydrocarbon fuels. With the possibility of long-term energy storage and re-electrification, hydrogen promises to promote the effective utilization of renewable and sustainable energy resources. Clean hydrogen can be produced through a renewable-powered water electrolysis process. Although alkaline water electrolysis is currently the mature and commercially available electrolysis technology for hydrogen production, it has several shortcomings that hinder its integration with intermittent and fluctuating renewable energy sources. The proton exchange membrane water electrolysis (PEMWE) technology has been developed to offer high voltage efficiencies at high current densities. Besides, PEMWE cells are characterized by a fast system response to fluctuating renewable power, enabling operations at broader partial power load ranges while consistently delivering high-purity hydrogen with low ohmic losses. Recently, much effort has been devoted to improving the efficiency, performance, durability, and economy of PEMWE cells. The research activities in this context include investigations of different cell component materials, protective coatings, and material characterizations, as well as the synthesis and analysis of new electrocatalysts for enhanced electrochemical activity and stability with minimized use of noble metals. Further, many modeling studies have been reported to analyze cell performance considering cell electrochemistry, overvoltage, and thermodynamics. Thus, it is imperative to review and compile recent research studies covering multiple aspects of PEMWE cells in one literature to present advancements and limitations of this field. This article offers a comprehensive review of the state-of-the-art of PEMWE cells. It compiles recent research on each PEMWE cell component and discusses how the characteristics of these components affect the overall cell performance. In addition, the electrochemical activity and stability of various catalyst materials are reviewed. Further, the thermodynamics and electrochemistry of electrolytic water splitting are described, and inherent cell overvoltage are elucidated. The available literature on PEMWE cell modeling, aimed at analyzing the performance of PEMWE cells, is compiled. Overall, this article provides the advancements in cell components, materials, electrocatalysts, and modeling research for PEMWE to promote the effective utilization of renewable but intermittent and fluctuating energy in the pursuit of a seamless transition to clean energy.

Carbon nanofiber (CNF) derived from carbonization of bacterial cellulose (BC), with a unique three-dimensional porous nanostructure, has received significant interest in electrochemical applications. In this study, CNF samples were physically activated in CO₂ at different temperatures and durations. Raman spectroscopy and FTIR analysis showed that CO₂ activation caused hexagonal lattice defects, disorder, and oxygen-related functional groups in an amorphous carbon structure. CNF surface morphology changed after physical activation, reducing fiber diameter to 55 nm and introducing mesopores. Through activation temperature and time adjustments, surface area (870.1 m²/g) and micropore surface area (535.6 m²/g) and pore volume (0.2148 cm³/g) increased. EDX elemental analysis showed that activated CNF had a carbon concentration of > 90 %, while XPS analysis showed surface functional groups like C-C (sp²) and C-C (sp³) hybridization, which could improve electrolyte ion adsorption and accessibility. Electrochemical properties improved owing to CO₂ activation. The optimal activation condition of 800 ℃ for 60 min resulted in the highest specific area capacitance of 552 mF cm⁻² at 1 mA cm⁻². This activated CNF electrode retained capacitance nearly unchanged up to 3,000 cycles. It also achieved the highest energy density of 76.7 mWh cm⁻² at 500 mW cm⁻². This study demonstrates the efficacy of CO₂ physical activation for enhancing the electrochemical properties of CNF electrodes. The findings also highlight the importance of tailoring activation conditions, providing valuable insights for the design of advanced energy storage materials.