Enhancing the Electrocatalytic Activity of Redox Stable Perovskite Fuel Electrodes in Solid Oxide Cells by Atomic Layer-Deposited Pt Nanoparticles

The carbon dioxide and steam co-electrolysis in solid oxide cells offers an efficient way to store the intermittent renewable electricity in the form of syngas (CO + H2), which constitutes a key intermediate for the chemical industry. The co-electrolysis process, however, is challenging in terms of materials selection. The cell composites, and particularly the fuel electrode, are required to exhibit adequate stability in redox environments and coking that rules out the conventional Ni cermets. La0.75Sr0.25Cr0.5Mn0.5O3 (LSCrM) perovskite oxides represent a promising alternative solution, but with electrocatalytic activity inferior to the conventional Ni-based cermets. Here, we report on how the electrochemical properties of a state-of-the-art LSCrM electrode can be significantly enhanced by introducing uniformly distributed Pt nanoparticles (18 nm) on its surface via the atomic layer deposition (ALD). At 850 °C, Pt nanoparticle deposition resulted in a ∼62% increase of the syngas production rate during electrolysis mode (at 1.5 V), whereas the power output was improved by ∼84% at fuel cell mode. Our results exemplify how the powerful ALD approach can be employed to uniformly disperse small amounts (∼50 μg·cm–2) of highly active metals to boost the limited electrocatalytic properties of redox stable perovskite fuel electrodes with efficient material utilization.</p

Plasma activated electrolysis for cogeneration of nitric oxide and hydrogen from water and nitrogen

With increasing global interest in renewable energy technology given the backdrop of climate change, storage of electrical energy has become particularly relevant. Most sustainable technologies (e.g., wind and solar) produce electricity intermittently. Thus, converting electrical energy and base molecules (i.e., H2O, N2) into energy-rich ones (e.g., H2, NH3) or chemical feedstock (e.g., NO) is of paramount importance. While H2O splitting is compatible with renewable electricity, N2 fixation is currently dominated by thermally activated processes. In this work, we demonstrate an all-electric route for simultaneous NO and H2 production. In our approach, H2O is reduced to H2 in the cathode of a solid oxide electrolyzer while NO is produced in the anode by the reaction of O2– species (transported via the electrolyte) and plasma-activated N2 species. High faradaic efficiencies up to 93% are achieved for NO production at 650 °C, and NO concentration is &gt;1000 times greater than the equilibrium concentration at the same temperature and pressure.</p

Engineering visible light emitting point defects in Zr-implanted polycrystalline AlN films

We have investigated the impact of thermal annealing gaseous atmosphere of argon, nitrogen, and forming gas on the structural and optical properties of thin polycrystalline AlN films subjected to high-energy zirconium ions implantation. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy measurements show that the structural and morphological properties of the Zr-implanted AlN films depend on the annealing gaseous environment. Post-implantation annealing under argon atmosphere yields the lowest structured surface roughness with increased grain size. Photoluminescence spectroscopy revealed multiple point defects and defect complexes related emission bands in the visible range. A series of absorption bands have been observed using photoluminescence excitation spectroscopy. The origin of the emission or absorption bands is identified and attributed to various types of point defects and defect complexes, theoretically reported for AlN. New emission and absorption peaks at 1.7eV (730nm) and 2.6eV (466nm), respectively, have been identified and attributed to the (ZrAl–VN)0 defect complexes

Rational Design of Photoelectrodes for the Fully Integrated Polymer Electrode Membrane–Photoelectrochemical Water-Splitting System: A Case Study of Bismuth Vanadate

Photoelectrochemical (PEC) reactors based on polymer electrolyte membrane (PEM) electrolyzers are an attractive alternative to improve scalability compared to conventional monolithic devices. To introduce narrow band gap photoabsorbers such as BiVO4 in PEM-PEC system requires cost-effective and scalable deposition techniques beyond those previously demonstrated on monolithic FTO-coated glass substrates, followed by the preparation of membrane electrode assemblies. Herein, we address the significant challenges in coating narrow band gap metal-oxides on porous substrates as suitable photoelectrodes for the PEM-PEC configuration. In particular, we demonstrate the deposition and integration of W-doped BiVO4 on porous conductive substrates by a simple, cost-effective, and scalable deposition based on the SILAR (successive ionic layer adsorption and reaction) technique. The resultant W-doped BiVO4 photoanode exhibits a photocurrent density of 2.1 mA·cm–2, @1.23V vs RHE, the highest reported so far for the BiVO4 on any porous substrates. Furthermore, we integrated the BiVO4 on the PEM-PEC reactor to demonstrate the solar hydrogen production from ambient air with humidity as the only water source, retaining 1.55 mA·cm–2, @1.23V vs RHE. The concept provides insights into the features necessary for the successful development of materials suitable for the PEM-PEC tandem configuration reactors and the gas-phase operation of the reactor, which is a promising approach for low-cost, large-scale solar hydrogen production.</p

Influence of Nd3+ doping on the structural and near-IR photoluminescence properties of nanostructured TiO2 films

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Sustainable Waste Management in Malaysia: Leveraging Supply Chain Solutions for a Greener Future

Sustainable waste management has become a critical global concern, and Malaysia is no exception. With the country's increasing urbanization and economic growth, waste generation has risen significantly, posing environmental and social challenges. This paper explores the concept of sustainable waste management in Malaysia and proposes leveraging supply chain solutions as a pathway towards a greener future. The study examines the current waste management practices, their limitations, and the potential environmental impacts. It highlights the need for integrated and innovative approaches encompassing the entire waste management supply chain, from collection to disposal. By adopting sustainable supply chain practices, such as waste segregation, recycling, and waste-to-energy conversion, Malaysia can achieve more efficient resource utilization, reduce greenhouse gas emissions, and minimize landfill usage. Furthermore, the paper addresses the role of government policies, private sector engagement, and public awareness in fostering a successful transition towards sustainable waste management. The findings and recommendations presented in this study contribute to the ongoing efforts to develop a comprehensive and eco-friendly waste management system in Malaysia and serve as a model for other developing nations facing similar challenges

Divacancy superstructures in thermoelectric calcium-doped sodium cobaltate

We have grown single crystals of Na$_x$Ca$_y$CoO$_2$ and determined their superstructures as a function of composition using neutron and x-ray diffraction. Inclusion of Ca$^{2+}$ stabilises a single superstructure across a wide range of temperatures and concentrations. The superstructure in the Na$^+$ layers is based on arrays of divacancy clusters with Ca$^{2+}$ ions occupying the central site, and it has an ideal concentration Na$_{4/7}$Ca$_{1/7}$CoO$_2$. Previous measurements of the thermoelectric properties on this system are discussed in light of this superstructure. Na$_{4/7}$Ca$_{1/7}$CoO$_2$ corresponds to the maximum in thermoelectric performance of this system.Comment: Produced using Revtex 4.1 and pdflatex. 7 Pages, 6 figure

Green synthesis of silver nanoparticles using <i>Atalantia monophylla</i>: A potential eco-friendly agent for controlling blood-sucking vectors

Abstract Developing floral-based replacement molecules might manage blood-sucking vectors in an eco-friendly way. Atalantia monophylla (Am) aqueous leaf extract (ALE) and silver nanoparticles (AgNPs) were evaluated against mosquitoes (Aedes vittatus, Anopheles subpictus, and Culex vishnui) and ticks (Haemaphysalis bispinosa, Rhipicephalus microplus, and R. sanguineus) at different concentrations. Phytochemical screening and AgNPs' synthesis were performed on ALE of A. monophylla. UV-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscope, and transmission electron microscope were used to examine the synthesized Am-AgNPs. A. monophylla's ALE included alkaloids, flavonoids, saponins, tannins, triterpenes, coumarins, anthraquinones, and phenolics. Am-AgNPs had a higher LC50 (22.19, 23.92, 26.09, 40.25, 51.87, and 60.53 μg·mL−1, respectively) than leaf aqueous extract (LAE) against Ae. vittatus, An. subpictus, Cx. vishnui, H. bispinosa, R. microplus, and R. sanguineus larvae. A. monophylla ALE and Am-AgNPs' bio-toxicity was investigated against aquatic and terrestrial non-target species (Acilius sulcatus, Anisops bouvieri, Araneus mitificus, and Cyrtophora moluccensis) with LC50 values ranging from 2,094.5 to 10,532.8 μg·mL−1, respectively. A. monophylla ALE and Am-AgNPs had little negative impacts on the chosen non-target fauna. Environmental protection is important nowadays. Green AgNPs are low-cost, readily accessible, environmentally safe, and effective pesticides. Am-AgNPs are effective alternative insecticides, requiring a considerable study on this plant to control blood-sucking vectors for worldwide human/animal health importance