Alternative Materials Research Articles

Effects of dietary fermented attachments of suspension cage as a replacement for sea mud on growth and intestinal health of sea cucumber Apostichopus japonicus

In the suspension cage culture process, regular cleaning to remove epiphytic organisms from the cage is essential to prevent economic losses due to the sinking of the cage. However, after cleaning, many of attachments from the suspension cage accumulate in the tidal flats, causing environmental pollution and resource wastage. Moreover, because sea cucumbers (Apostichopus japonicus) are sedimentary food organisms, sea mud is typically added to their feed to varying degrees. However, long-term excavation of sea mud can destroy the marine environment. Therefore, developing an alternative new raw feed material to replace sea mud in sea cucumber feed is necessary to promote sustainable development of the A. japonicus aquaculture industry. The aim of this study was to explore the feasibility of using fermented attachments of suspension cage (FASC) as a raw feed material for A. japonicus. Different FASC concentrations (0, 25, 50, 75, and 100 %) were used in A. japonicus feed for 60 d. Replacing Sea mud with 100 % FASC significantly improved sea cucumber growth, reduced the feed coefficient, significantly increased the activity of intestinal digestive enzymes, improved intestinal structure, and enriched intestinal microbiome diversity. Furthermore, expressions of growth genes mapk-7 and fgfr-1 significantly increased in the 100 % FASC treatment compared with that in the control, and that of negative growth regulator gene gdf-8 was inhibited. The results suggested the potential of FASC as a new raw feed material for A. japonicus.

Catalytic pyrolysis of polystyrene over rice husk silica-derived traditional and hierarchical green MWW zeolites

This work aimed at the green synthesis of MWW zeolites using rice husk silica as an alternative raw material. It was also performed a post-synthesis desilication procedure with NaOH and CTABr aiming to obtain MWW zeolites with improved accessibility. The set of characterization techniques (XRD, 27Al MAS NMR, N2 physisorption, SEM, TEM, and Pyridine-FTIR) revealed the phase purity and combined structure of micro-mesopores after desilication. The zeolites were evaluated as catalysts for polystyrene pyrolysis, producing benzene, toluene and ethylbenzene, besides styrene monomers, and dimers. Without any catalyst, polystyrene produces only styrene monomers, dimers and trimers. The desilication increases the amount of Brønsted and Lewis sites and the external area, catalyzing the production of polyaromatics and naphthalene derivatives. The activation energy decreased for the catalyzed reactions, reflecting other reaction pathways.

Development of Biocompatible Coatings with PVA/Gelatin Hydrogel Films on Vancomycin-Loaded Titania Nanotubes for Controllable Drug Release.

This study investigates the utilization of poly(vinyl alcohol) (PVA)/gelatin hydrogel films cross-linked with glutaraldehyde as a novel material to coat the surface of vancomycin-loaded titania nanotubes (TNTs), with a focus on enhancing biocompatibility and achieving controlled vancomycin release. Hydrogel films have emerged as promising candidates in tissue engineering and drug-delivery systems due to their versatile properties. The development of these hydrogel films involved varying the proportions of PVA, gelatin, and glutaraldehyde to achieve the desired properties, including the gel fraction, swelling behavior, biocompatibility, and biodegradation. Among the formulations tested, the hydrogel with a PVA-to-gelatin ratio of 25:75 and 0.2% glutaraldehyde was selected to coat vancomycin-loaded TNTs. The coated TNTs demonstrated slower release of vancomycin compared with the uncoated TNTs. In addition, the coated TNTs demonstrated the ability to promote osteogenesis, as evidenced by increased alkaline phosphatase activity and calcium accumulation. The vancomycin-loaded TNTs coated with hydrogel film demonstrated effectiveness against both E. coli and S. aureus. These findings highlight the potential benefits and therapeutic applications of using hydrogel films to coat implant materials, offering efficient drug delivery and controlled release. This study contributes valuable insights into the development of alternative materials for medical applications, thereby advancing the field of biomaterials and drug delivery systems.

Lignocellulose sustainable composites from agro-waste Asparagus bean stem fiber for polymer casting applications: Effect of fiber treatment

In the past decades, lignocellulose fibers have attracted significant attention due to their low density, environmental friendliness, and biodegradability. Consequently, researchers are intensifying their efforts to explore the potential of lignocellulosic fibers as sustainable alternatives to synthetic fibers in polymer composites. Among various natural fibers identified as potential reinforcements, agro-waste from the Asparagus Bean stem (ABS) which has been discarded as landfill after harvest has emerged as a promising source of lignocellulose fibers for promoting sustainability. This study investigates the reinforcement suitability of ABSF in polymer matrices. A water-retting process was used for extraction, followed by treatment with a 5 % alkali solution. Cellulose content was enhanced to 65 wt%, and fiber density increased to 1.13 g/cm3 after chemical treatment. Thermogravimetric analysis indicated improved thermal stability of the treated fibers up to 247 °C. Morphological analysis showed increased surface roughness and impurity removal. To evaluate the reinforcing effect of the chemical treatment, epoxy composites with 10 wt% reinforcement were developed. The mechanical properties of these composites improved significantly, with more than 1.1 times when used alkali-treated ABSF as reinforcement. Flexural properties were substantially enhanced, with flexural strength increasing from 90.53 MPa to 122.71 MPa and flexural modulus from 2.41 GPa to 2.95 GPa due to better fiber-matrix interaction and removal of weak, amorphous constituents. The primary objective of this study is to demonstrate that ABSF is a viable alternative raw material for composite reinforcement, suitable for developing lightweight structural applications.

Green, sustainable and eco-friendly approach for extraction of silica nanoparticles from Ananas comosus and Saccharum ravannae: a comparative study of dye removal from aqueous solution

ABSTRACT Silica nanoparticles (SiNPs) were extracted in an eco-friendly manner from the crown of Ananas comosus (pineapple, AC SiNPs) and leaves of Saccharum ravannae (weed grass, SR SiNPs). Initial studies were performed to examine the adsorption of various cationic (Methylene blue, MB; Safranin, SA), anionic (Trypan Blue, TB; Eosin yellow, EY), and neutral dyes (Neutral red, NR). The investigation revealed that the maximum removal was achieved at an adsorbent dose of 1 g L−1 at an optimum pH of 7–8, at an equilibrium contact time of ∼15 mins for the dye concentration of 10 mg L−1 at 298 K. Adsorption followed the pseudo-second-order kinetic model and Freundlich isotherm model, indicating multi-layered heterogeneous adsorption. The maximum adsorption capacity (qmax) for MB, SA, and NR was found to be 81.3 mg g−1, 21.74 mg g−1, and 24.75 mg g−1 respectively, for AC SiNPs. The qmax for SR SiNPs was found to be 78.12 mg g−1, 47 mg g−1, and 70 mg g−1 for MB, SA, and NR respectively. Moreover, desorption studies showed that till 4–5 cycles, >90% of the removal efficiency was retained. Thus, the biogenic and non-toxic SiNPs can be a greener, eco-friendly alternative material for dye removal from wastewater.

Monkeypox in Bulgaria: Significance of Various Clinical Samples, Clinical Manifestation, and Molecular Detection.

Background/Objectives: Monkeypox (mpox) is currently the most common orthopoxvirus (OPXV) zoonotic disease, and, since 2022, there has been atypical person-to-person transmission observed in non-endemic countries. The present study aimed to investigate the frequency of monkeypox virus (MPXV) and OPXV DNA detection in recommended and alternative clinical materials taken during the acute and convalescent phases of infection in Bulgarian patients. Methods: The study included laboratory investigation by real time PCR of 181 clinical samples from 42 Bulgarian patients with possible mpox infections. Results: MPXV DNA was detected in 23/181 (12.71%), and OPXV DNA in 20/181 (11.05%) clinical samples. There were six mpox-confirmed patients aged 23 to 44. At the highest frequency, MPXV and OPXV DNA were detected in samples of vesicular contents (6/6) and nasal/oropharyngeal secretions (5/6 and 4/6) during the first three days from the appearance of clinical symptoms. We demonstrated MPXV and OPXV DNA in alternative samples (urine, feces, ejaculate, and saliva), and in follow-up patient samples, taken two weeks after mpox confirmation in the convalescent phase (vesicular contentsand urine). Conclusions: Our findings suggested that MPXV may be detected in a larger set of clinical materials, including alternatives, where the virus can persist for more than two weeks.

Biological and physicochemical characterization of carbonated hydroxyapatite-honeycomb-polyethylene oxide bone scaffold fabricated using the freeze-drying method

In this work, a carbonated hydroxyapatite/honeycomb/polyethylene oxide (CHA/HCB/PEO) scaffold was fabricated using the freeze-drying method. The CHA bioceramic component was synthesized from oyster shells using the precipitation method. HCB and PEO act as reinforcing materials that influence the physicochemical properties of the scaffold and as antibacterial agents on the scaffold. The CHA produced was B-type, confirmed by Fourier transform infrared (FTIR) and x-ray diffractometer (XRD) spectra of the CHA. FTIR analysis of the scaffold demonstrated the presence of functional group vibrations originating from PEO and HCB, affirming the successful application of the freeze-drying method, which preserved the polymer content within the scaffold during the evaporation process, thus facilitating pore formation. The XRD results show that a lower CHA concentration is associated with a smaller size of the scaffold crystallites, potentially inducing dislocations favorable for cellular proliferation. The porosity of the formed scaffold is in the ideal range of >60% with CHA concentration of 5 and 10 wt%. The size of the pores that formed on the scaffold was 3–69 μm, classifying them within the micropore category. The in vitro test results in the form of an antibacterial test revealed that the scaffold could inhibit S. aureus and E. coli bacteria. Notably, a scaffold consisting of 10 wt% of CHA had a larger zone of inhibition diameter, 10.083 ± 0.104 for S. aureus and 10.517 ± 0.247 mm for E. coli. The MTT assay and cell morphology MC3T3E1 results in the scaffold show that the CHA/HCB/PEO scaffold is non-cytotoxic and can facilitate cells to attach and proliferate. The cell viability of the scaffold was 96.23% at the concentration of 31.25 μg ml−1, and the IC50 value was at 16144 μg ml−1. Therefore, CHA/HCB/PEO composites can be an alternative material in scaffold fabrication for bone tissue engineering.

Selected Physical and Mechanical Properties of Particleboards Manufactured from Plantation Willow and Poplar Wood.

This research focuses on producing particleboards from the biomass of plantation willow (Salix viminalis L.) and poplar (Populus spp.), aiming to explore their feasibility as sustainable materials for various applications. Fast-growing willow and poplar are known for their rapid growth and suitability for energy production. They present an intriguing alternative as raw materials with added value for particleboard manufacturing. This study investigates the selected mechanical and physical properties of the produced particleboards, considering parameters such as density profile, bending strength, modulus of elasticity, internal bond, water absorption, thickness swelling, and screw withdrawal resistance. The research results were also compared between different mass shares of willow and poplar particles in the particleboards. The results show that the panels produced entirely from the tested alternative raw materials had a modulus of rupture of 21.7 N mm-2 compared to 14.6 N mm-2 for the reference panels, with an internal bond of about 2.02 N mm-2 compared to 0.65 N mm-2 for the reference panels. The thickness swelling after 24 h of soaking was about 24.2% compared to 42.2% for reference panels. The findings underscore the promising potential of willow and poplar-based particleboards as eco-friendly alternatives in the construction and furniture industries, contributing to resource efficiency and carbon emission reduction efforts.

Graphene-based nanocomposites as gamma- and X-ray radiation shield

Commonly used materials for protection against ionizing radiation (gamma and X-ray energy range) primarily rely on high-density materials, like lead, steel, or tungsten. However, these materials are heavy and often impractical for various applications, especially where weight is a key parameter, like in avionics or space technology. Here, we study the shielding properties of an alternative light material—a graphene-based composite with a relatively low density ~ 1 g/cm3. We demonstrate that the linear attenuation coefficient is energy of radiation dependent, and it is validated by the XCOM model, showing relatively good agreement. We also show that the mass attenuation coefficient for selected radiation energies is at least comparable with other known materials, exceeding the value of 0.2 cm2/g for higher energies. This study proves the usefulness of a commonly used model for predicting the attenuation of gamma and X-ray radiation for new materials. It shows a new potential candidate for shielding application.

Water-resistant properties improvement of aluminium oxide nanoparticles treated kraft paper by sparking process

This study aims to improve the hydrophobicity of non-sizing Kraft paper (KP) surfaces using nanoparticle coating through the sparking process. The aluminium oxide nanoparticles (Al2O3 NPs) were used for surface modification on KP through the sparking process, optimizing with varying sparking cycles (5–20 times), annealing temperatures (60–120 °C), and annealing times (1–3 h). Then, the Al2O3 NPs treated KP were examined by XRD, FT–IR, SEM, EDX, and AFM, respectively. The water contact angle (CA) was used to examine the water-resistant properties of the treated KP. The treated KP with varying sparking cycles up to 15 times showed higher surface coverage and enhanced fine roughness surface on the treated KP. The fine roughness surface of KP induced hydrophobicity (126° of CA) on the surface of KP at 15 sparking cycles. Similarly, the higher CA for hydrophobicity surface on treated KP from varying temperatures and times of the annealing process was demonstrated at 120° for 3 h. Therefore, the treated KP with 15 times of sparking cycle, annealing temperature at 120 °C for 3 h was defined as the optimized condition in this work. Furthermore, the developments of hydrophobicity and superhydrophobicity on the treated KP with CA at 135 and 155° were observed for the non-sizing and sizing KP, respectively. This indicated that the increased surface roughness and reduced surface energy of the treated KP simultaneously delayed the water absorption times on the KP surface. Consequently, the nano-treating of Al2O3 NPs using the sparking process shows the promising feature of inducing superhydrophobicity on the KP surface, which can produce a water-repellent corrugated box as an alternative packaging material.

Low carbon multi-binder composite using lithomargic soil, biomass, and calcined seashell powder for sustainable bricks

Bricks are manufactured using clays, which are fired at temperatures ranging from 1000 to 1200 °C. Due to the lack of quality clay, it is necessary to find alternate soils and waste materials for manufacturing bricks. The use of agricultural, aqua-cultural, and industrial wastes in the manufacturing of construction bricks leads to low-carbon material. This addresses the problem of agro-aqua-industrial waste disposal. The present study focuses on the utilization of biomass (BM) and slaked seashell powder (SSP) in compressed soil bricks made with locally available lithomargic soil (LS). The proposed soil bricks are prepared with 85% processed lithomargic soil, 12.5% biomass and 2.5% seashell powder. The reaction of multi-binder materials has been activated by one-part activation. The cast soil blocks are temperature cured at 100 °C, 250 °C, 500 °C & 750 °C to understand the effect of temperature on the hydration process of binder material. The compressed soil bricks are tested for compressive strength, initial rate of absorption, water absorption test, chloride content, sulphate content, microstructure analysis and thermal conductivity. The strength of soil bricks in bonding and in masonry, 3 prism and 4 prism tests were also conducted. Overall results indicate that bio-based alkali-activated brick masonry is superior for real-time adaptation because it reaches 10 MPa to 11.2 MPa compressive strength and 0.98 MPa to 1.2 MPa shear strength with curing at 500 °C.

Assessment of cranial reconstruction utilizing various implant materials: finite element study

The human head can sometimes experience impact loads that result in skull fractures or other injuries, leading to the need for a craniectomy. Cranioplasty is a procedure that involves replacing the removed portion with either autologous bone or alloplastic material. While titanium has traditionally been the preferred material for cranial implants due to its excellent properties and biocompatibility, its limitations have prompted the search for alternative materials. This research aimed to explore alternative materials to titanium for cranial implants in order to address the limitations of titanium implants and improve the performance of the cranioplasty process. A 3D model of a defective skull was reconstructed with a cranial implant, and the implant was simulated using various stiff and soft materials (such as alumina, zirconia, hydroxyapatite, zirconia-reinforced PMMA, and PMMA) as alternatives to titanium under 2000N impact forces. Alumina and zirconia implants were found to reduce stresses and strains on the skull and brain compared to titanium implants. However, PMMA implants showed potential for causing skull damage under current loading conditions. Additionally, PMMA and hydroxyapatite implants were prone to fracture. Despite these findings, none of the implants exceeded the limits for tensile and compressive stresses and strains on the brain. Zirconia-reinforced PMMA implants were also shown to reduce stresses and strains on the skull and brain compared to PMMA implants. Alumina and zirconia show promise as alternatives to titanium for the production of cranial implants. The use of alternative implant materials to titanium has the potential to enhance the success of cranial reconstruction by overcoming the limitations associated with titanium implants.Graphical

Mechanistic insights into molybdenum immobilization within geopolymer waste form

Molybdenum (Mo) tends to form highly mobile, non-sorbing complex redox species, which complicates its immobilization and encapsulation in cement and glass matrices. This study explores the potential of incorporating Mo into an alternative green cementitious material known as geopolymer (GP). By employing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), morphological analysis, and nitrogen adsorption-desorption techniques, we obtained comprehensive insights into the chemical behavior of Mo and its impact on the morphology and structure of the GP matrix. XRD and TGA analysis demonstrated that increasing Mo content significantly enhances the crystallinity and thermal stability of the GP matrix, attributed to Mo field effects. High-resolution SEM, TEM, and EDS mapping revealed the structural encapsulation of Mo-rich cavities within the GP waste form. A decrease in leaching rates with higher Mo content, alongside reduced pore volume and pore size, underscores the material's chemical durability. Post-leaching characterizations confirmed that the GP retains excellent structural strength with minimal changes in mesoporosity and surface area. This resilience highlights the effectiveness of GPs in immobilizing non-sorbing species like MoO32−, making them ideal for long-term waste management.

Manufacturing and performance of eco-efficient cementitious blocks for thermal cycling in thermal energy storage

Solar energy is a promising renewable option to provide energy demands in combination with conventional energy sources. However, to enhance the integration of renewable energies into the industrial section, it is necessary to employ thermal energy storage media. Among different thermal energy storage options, concrete has proven to be a very effective sensible thermal energy storage solution. However, its main raw material (i.e., the Portland cement), is the cause of huge CO2 emissions to the environment. This study focuses on the design, manufacture, assembly and experimentation of thermal energy storage blocks made of alternative binders in substitution of Portland cement: i.e., hybrid materials and alkaline activated materials. The thermal energy storage blocks have been thermally cycled, with a charging temperature of 228 °C and a discharging temperature of 30 °C, in order to analyze the operational times and temperatures. The results obtained are very promising and comparable to those of the Portland cement system. Charging times have improved, with the alternative materials achieving temperature increases of up to 4%, while greater stabilization has been achieved during discharge, with the fluid reaching temperatures up to 6% higher than the reference system. These advancements support efficient, sustainable thermal energy storage technologies.

Use of pumice stone and silica fume as precursor material for the design of a geopolymer.

Geopolymers are alternative materials to cement because they require less energy in their production process; hence, they contribute to the reduction in CO 2 emissions. This study aims to evaluate the possibility of using industrial residues such as silica fume (SF) to improve the physical and mechanical properties of a pumice stone (PS)-based geopolymer. Through an experimental methodology, the process starts with the extraction, grinding, and sieving of the raw material to carry out the physical and chemical characterization of the resulting material, followed by the dosage of the geopolymer mixture considering the factors that influence the resistance mechanical strength. Finally, the physical and mechanical properties of the geopolymer were characterized. This research was carried out in four stages: characterization of the pumice stone, design of the geopolymer through laboratory tests, application according to the dosage of the concrete, and analysis of the data through a multi-criteria analysis. It was determined that the optimal percentage of SF replacement is 10%, which to improves the properties of the geopolymer allowing to reach a maximum resistance to compression and flexion of 14.10 MPa and 4.78 MPa respectively, showing that there is a direct relationship between the percentage of SF and the resistance. Geopolymer preparation involves the use of PS powder with a composition rich in silicon and aluminum. The factors influencing strength include the ratio of sodium silicate to sodium hydroxide, water content, temperature, curing time, molarity of sodium hydroxide, and binder ratio. The results showed an increase in the compression and flexural strength with 10% SF replacement. The geopolymer's maximum compressive strength indicates its non-structural use, but it can be improved by reducing the PS powder size.

Reka Bentuk Blok Batik daripada Bahan Kitar Semula Pengikat Mekanikal Nat

Batik blocks are tools used by batik makers to apply and shape pattern designs on fabric. The production of batik patterns is usually done using resist techniques such as batik blocks, batik canting, and batik screens. Batik blocks are among the earliest forms of batik introduced and produced in Malaysia. This study aims to apply recycled mechanical fastener nuts material as an alternative to batik blocks. The primary focus is on producing blocks using recycled fastener nuts material in the making of batik blocks. The block production process follows the same method as traditional copper blocks but uses fastener nuts as a new alternative material. The aim of exploring this new material aims to assess the potential of recycled mechanical fastener nuts material for reuse. This can provide ideas and innovation to the batik industry enriching motifs and pattern designs in Malaysia, as well as helping to find the identity of Malaysian batik. Data was collected from observations and the gathering of recycled mechanical fastener nut materials from vehicle and motorcycle workshops. Several block production processes were conducted in stages. The research findings indicate that mechanical fastener nuts have the potential to be used as batik blocks. Hopefully, this research can assist batik entrepreneurs, especially the younger generation, in promoting the batik industry by exploring more material uses in block production.

Effects of Fermentation with Kombucha Symbiotic Culture of Bacteria and Yeasts on Antioxidant Activities, Bioactive Compounds and Sensory Indicators of Rhodiola rosea and Salvia miltiorrhiza Beverages.

Kombucha is a well-known fermented beverage traditionally made from black tea infusion. Recent studies have focused on finding alternative materials to create novel kombucha beverages with various health benefits. In this study, we prepared and evaluated two novel kombucha beverages using Rhodiola rosea and Salvia miltiorrhiza as materials. The effects of fermentation with the residue of these plants on the kombucha were also investigated. The antioxidant activities, total phenolic contents, and concentrations of the bioactive compounds of the kombucha beverages were determined by the Trolox equivalent antioxidant capacity test, ferric-reducing antioxidant power test, Folin-Ciocalteu method, and high-performance liquid chromatography, respectively. The results revealed that the kombucha beverages made with Rhodiola rosea and Salvia miltiorrhiza had strong antioxidant capacities and abundant phenolic contents. Additionally, the kombucha fermented with Rhodiola rosea residue had higher FRAP, TEAC and TPC values than that fermented without residue. On the other hand, the Salvia miltiorrhiza kombucha fermented with residue had similar FRAP and TEAC values but lower TPC values compared to that fermented without residue. The correlation analysis showed that gallic acid, salidroside, and tyrosol were responsible for the antioxidant abilities and total phenolic contents of the Rhodiola rosea kombucha, and salvianolic acid A and salvianolic acid B contributed to the antioxidant abilities of the Salvia miltiorrhiza kombucha. Furthermore, the kombucha fermented with Rhodiola rosea residue had the highest sensory scores among the kombucha beverages studied. These findings suggest that Rhodiola rosea and Salvia miltiorrhiza are suitable for making novel kombucha beverages with strong antioxidant abilities and abundant phenolic contents, which can be used in preventing and managing oxidative stress-related diseases.

Kinetics of Oxygen Catalyst Based on Pyrochlore Oxide Nano-Particles for Low Temperature Water Electrolysis

Alkaline water electrolysis is carried out at 60 to 80 oC using nickel-based electrode materials and highly concentrated KOH solutions, which make highly corrosive environment against the electrodes, the separator, the current collector, and the others of the cell. Reduction in operating temperature would be preferable to suppress corrosion, although it would also make the catalytic activity for OER and HER down, making the cell voltage up. Since oxygen evolution is known as a high overpotential reaction which is more than 400 mV with nickel-based oxides at 60 oC or more, and alternative materials with lower overpotential and higher stability for OER in AWE have been needed. This paper presents a novel oxygen catalyst nano-particles based on bismuth ruthenium oxide, in which ruthenium at the B site in the pyrochlore structure is partly replaced with manganese1).Mn-doped bismuth ruthenium oxide (MBRO) was prepared by precipitation of metal hydroxide precursor, which had been obtained by addition of NaOH solution into the metal salt solution containing Bi(III) and Ru(III) with Mn(II), followed by calcination at 600 oC. XRD, EDX, EXAFS, ICP-AES, and RBS were used for structural and compositional analyses of MBRO. The obtained oxide was added into distilled water and the solution was treated by ultrasonic vibration to make a suspension, which was then dropped on a titanium disk (4 mm diam.) and dried at RT for 24 h, resulting in oxide particles-coated titanium disk, in which no binders or ionomers were used in the process. The disk was mounted in a commercial rotating disk electrode and was used as the working electrode with a platinum counter electrode, an Hg/HgO reference electrode, and 0.1 mol/L KOH solution. Polarization curves were measured by LSV for OER, of which the results were analyzed to obtain the onset potential, Tafel slope, exchange current density. All measurements were performed at RT (25 oC).EDX and EXAFS studies of MBRO showed that Ru(IV) was replaced with Mn(IV) at the B-site of pyrochlore structure, and this doping made a single phase of pyrochlore structure oxide without sub-product up to 30 at% replacement . Linear sweep voltammetry revealed the overpotential of MBRO for OER was less than 200 mV and the Tafel slope analysis of the LSV curve gave 40 mV/dec or less. The onset potential and the Tafel slope were almost the same when Ru:Mn atomic ratio of MBRO was changed from 100:0 to 70:30 at%. Further analysis of the polarization curve indicated the exchange current density slightly decreased with increasing Mn ratio. These results suggest that Ru is the active site for OER but Mn is as well. The Tafel slope of OER catalysts reported in literatures is mostly 60 mV/dec or more, including more than 200 mV/dec of nickel-based oxides2,3). Therefore, MBRO is a hyper catalytic oxide for OER in alkaline media and can significantly reduce the overpotential of the anode in AWE even at ambient temperature.Ref.1) M. Morimitsu, Patent US.2022085387.A1.2) T. Shinagawa, A. T. Garcia-Esparza, K. Takanabe, Scientific Reports, Vol. 5, Article No.13801 (2015).3) S. Yagi, et al., Nature Communications, Vol. 6, Article No. 8249 (2015).

Evolution of 2PB/3PB Transport Pathways in Oxygen Electrodes during Degradation Test: A Perspective from Electro-Chemo-Mechanical Coupling on Microstructures

The solid oxide electrolysis cell (SOEC) has garnered significant attention over the past decades for hydrogen generation integrated with intermittent renewable energy [1]. However, a major hurdle in the commercialization of SOEC is cell degradation when operated beyond 1000 hours [2]. SOEC degrades two times more quickly than the same cell operated in fuel cell mode [3]. Perovskite oxygen electrodes (OEs), such as La1-xSrxCo1-yFeyO3-δ (LSCF), exhibit flexible oxygen stoichiometry [4-6] depending on the operating conditions. The delamination failure in perovskite OEs arises from a mismatch between the slower O2 evolution rate at the surface and the rapid O2 current in the bulk from the electrolyte (EL), which causes variations in oxygen stoichiometry. This variation in oxygen stoichiometry enhances bonding, contracts lattice volume, and leads to chemical stress at the OE/EL interface [7].In this research, we aim to construct an electro-chemo-mechanically coupled model with synthetic microstructures (Fig.1a) to explore the intricate interactions between delamination at the OE/EL interface and oxygen ion transport pathway evolution. The Dream 3D software will be utilized for microstructure generation, Matlab for mesh preparation, and Comsol for Multiphysics simulation. We will examine two OE configurations known for achieving high electrocatalytic activity [8]: single layer and bilayer OEs . For the single layer configuration, La0.6Sr0.4Co0.4Fe0.6O3 (LSCF) [9, 10] serves as the sole electrode material. For bilayer OEs, we incorporate SrTa0.1Co0.9O3 (SCT) [11, 12] as the capping layer for electrocatalytic activity, with LSCF acting as the supporting backbone. The evolution of two transport pathways (Fig.1b&c), double phase boundary (2PB) and tripe phase boundary (3PB), in different configurations during long-term degradation tests will be evaluated by coupling the models with experimental polarization curves and electrochemical impedance spectra. The investigations will focus on the effects of delamination resulting from lattice volume variations on shifting of transport pathways (Fig.1d) in different OE configurations. References Nechache, A. and S. Hody, Alternative and innovative solid oxide electrolysis cell materials: A short review. Renewable and Sustainable Energy Reviews, 2021. 149.Rashkeev, S.N. and M.V. Glazoff, Atomic-scale mechanisms of oxygen electrode delamination in solid oxide electrolyzer cells. International Journal of Hydrogen Energy, 2012. 37(2): p. 1280-1291.Moçoteguy, P. and A. Brisse, A review and comprehensive analysis of degradation mechanisms of solid oxide electrolysis cells. International Journal of Hydrogen Energy, 2013. 38(36): p. 15887-15902.Adler, S.B., Chemical Expansivity of Electrochemical Ceramics. Journal of the American Ceramic Society, 2001. 84(9): p. 2117-2119.Atkinson, A. and T.M.G.M. Ramos, Chemically-induced stresses in ceramic oxygen ion-conducting membranes. Solid State Ionics, 2000. 129(1): p. 259-269.Bishop, S.R., K.L. Duncan, and E.D. Wachsman, Defect equilibria and chemical expansion in non-stoichiometric undoped and gadolinium-doped cerium oxide. Electrochimica Acta, 2009. 54(5): p. 1436-1443.Cook, K., J. Wrubel, Z. Ma, K. Huang, and X. Jin, Modeling Electrokinetics of Oxygen Electrodes in Solid Oxide Electrolyzer Cells. Journal of The Electrochemical Society, 2021. 168(11): p. 114510.Laguna-Bercero, M.A., H. Monzón, A. Larrea, and V.M. Orera, Improved stability of reversible solid oxide cells with a nickelate-based oxygen electrode. Journal of Materials Chemistry A, 2016. 4(4): p. 1446-1453.Mogensen, M.B., M. Chen, H.L. Frandsen, C. Graves, J.B. Hansen, K.V. Hansen, A. Hauch, T. Jacobsen, S.H. Jensen, T.L. Skafte, and X. Sun, Reversible solid-oxide cells for clean and sustainable energy. Clean Energy, 2019. 3(3): p. 175-201.Jiang, S.P., Challenges in the development of reversible solid oxide cell technologies: a mini review. Asia-Pacific Journal of Chemical Engineering, 2016. 11(3): p. 386-391.Huang, K. and Y. Wen, Electrochemical Performance of New Bilayer Oxygen Electrode for Reversible Solid Oxide Cells. ECS Meeting s, 2021. MA2021-03(1): p. 138-138.Huang, K., Method to Make Isostructural Bilayer Oxygen Electrode. 2020, University of South Carolina: US. Figure 1

(Invited) The U.S. Department of Energy’s Hydrogen Consortium for Advanced Water Splitting Materials

The goals of the Hydrogen and Fuel Cell Technologies Office (HFTO) support those of the Biden Administration to build a clean and equitable energy economy and address the climate crisis through development and deployment of hydrogen technologies to the benefit of all Americans. HFTO is dedicated to meeting the goals of DOE’s Hydrogen Shot,1 which targets affordable clean hydrogen production at $1/kg within the decade, and the H2@Scale Initiative,2 which aims to advance affordable hydrogen to enable decarbonization and revenue opportunities across multiple sectors.HFTO’s HydroGEN consortium (https://www.h2awsm.org) for advanced water splitting (AWS) materials, part of the DOE’s Energy Materials Network (EMN), focuses on multiple clean hydrogen production pathways, including several relevant to renewable fuels via artificial photosynthesis. Since the consortium’s establishment in 2016, HydroGEN researchers have made significant progress in the areas of low and high temperature electrolysis, as well as solar thermochemical (STCH), and most relevant here, photoelectrochemical (PEC) hydrogen production pathways. The HydroGEN consortium facilitates collaborations between national laboratories, academia, and industry, bringing together world-class technical expertise with state-of-the-art facilities made available to project partners. HydroGEN offers an extensive collection of materials research capabilities for addressing R&D challenges. Project participants can choose from over 40 unique capability nodes. Each capability node is comprised of a combination of a tool, technique, and expertise that is unique to the national laboratory system.HydroGEN has supported over 30 competitively selected R&D projects with industry and academic partners by providing streamlined access to national lab resources and expertise. The consortium is also involved in fostering cross-cutting activities to advance material performance and durability through community engagement and protocol development and initiating critical laboratory-led efforts to address specific R&D gaps in the AWS portfolio.A new cohort of solar fuels focused projects were recently selected through the Funding Opportunity Announcement (FOA) Number: DE-FOA-0002792 with additional funding in this area expected in the future. A total of 11 new projects were selected, six in PEC and five in STCH, to work with the HydroGEN consortium towards advancing solar fuels production technology. Projects from both technology pathways must define materials metrics and targets for meeting the interim hydrogen cost target of $2/kg-H2 with extrapolation to additional requirements for meeting $1/kg-H2.Selected PEC projects focused on the development of materials or material systems for efficient and durable PEC water-splitting with a focus on innovations in bandgap and bandgap alignment, functional interfaces, stable surface catalysis, and protective coatings. A successful PEC photoelectrode project will need to achieve 15% STH efficiency for the entirety of operation exceeding 1,000 hours, with proposed pathways for achieving efficiencies up to 25% and durability up to 10,000 hours. Further, PEC systems will be required to demonstrate hydrogen production at a rate of 0.1 g/h for diurnal operation over two weeks.Selected STCH projects focused on accelerating discovery, development, and demonstration of alternative redox materials for a two-step STCH process and addressing projected costs and materials challenges associated with the required operating temperatures. Successful STCH projects will need to include a demonstration of the STCH process using sunlight or simulated sunlight. STCH systems must demonstrate hydrogen production at a rate of 1 g/h for diurnal operation over two weeks.For the first time, in line with the Justice40 Initiative,3 applicants were required to submit DEIA (diversity equity, inclusion, and accessibility) plans. Objectives from these plans were incorporated into the project objectives with specific goals identified for each year.Despite the progress, there is still significant ground to be covered through water splitting materials R&D. With the support of HydroGEN, these selected projects will help to address remaining challenges and enable low-cost and large-scale hydrogen production. An overview of consortium and project goals and objectives will be discussed. Hydrogen Shot | Department of EnergyH2@Scale | Department of Energy,The Justice40 initiative, created by Executive Order 14008, establishes a goal that 40% of the overall benefits of certain federal investments flow to disadvantaged communities. Figure 1