Metaphosphate Research Articles

Enhanced electrochemical activity by NiCo-P nano-particles modified Co-MOF nanorods

The design and preparation of high-performance electrode materials are among the most extensively researched topics in supercapacitor studies. By combining the three-dimensional structure and compatibility of cobalt-based metal-organic framework (Co-MOF) with the high redox activity of metal phosphates, a green, efficient, and safe co-precipitation and electro-deposition strategy was employed to fabricate the Co-MOF@NiCo-P heterostructure composite electrode material, with NiCo-P nanoparticles uniformly decorated on the surface of Co-MOF, addressing the issues of limited conductivity of Co-MOF and the tendency of NiCo-P to aggregate when grown in situ on foam nickel. In a three-electrode system, the Co-MOF@NiCo-P electrode exhibits specific capacities of 1389.8 F g−1 at 1 A g−1 and 964.3 F g−1 at 20 A g−1. The assembled Co-MOF@NiCo-P//AC hybrid supercapacitor device demonstrates energy densities of 54.08 Wh kg−1 (22.92 Wh kg−1) and power densities of 825 W kg−1 (8250 W kg−1), showing promising application prospects. This research offers a novel method for developing high-performance electrode materials.

Modification of Lithium‐Rich Manganese Oxide Materials: Coating, Doping and Single Crystallization

AbstractThe increasing demand for portable electronics, electric vehicles and energy storage devices has spurred enormous research efforts to develop high‐energy‐density advanced lithium‐ion batteries (LIBs). Lithium‐rich manganese oxide (LRMO) is considered as one of the most promising cathode materials because of its high specific discharge capacity (>250 mAh g−1), low cost, and environmental friendliness, all of which are expected to propel the commercialization of lithium‐ion batteries. However, practical applications of LRMO are still limited by low coulombic efficiency, significant capacity and voltage decay, slow reaction kinetics, and poor rate performance. This review focus on recent advancements in the modification methods of LRMO materials, systematically summarizing surface coating with different physical properties (e. g., oxides, metal phosphates, metal fluorides, carbon, conductive polymers, lithium compound coatings, etc.), ion doping with different doping sites (Li sites, TM sites, O sites, etc.), and single crystal structures. Finally, the current states and issues, key challenges of the modification of LRMO are discussed, and the perspectives on the future development trend base on the viewpoint of the commercialization of LRMO are also provided.

Electrodeposited zinc cobalt bimetallic phosphate as a bifunctional catalyst for hydrogen evolution and urea oxidation

The theoretical potential of the urea oxidation reaction (UOR) is a mere 0.37 V(vs.RHE), significantly lower than the 1.23 V (vs. RHE) of the oxygen evolution reaction (OER). Thus, substituting the OER with the UOR can effectively reduce the voltage required for electrolysis. Transition metal phosphates (TM-Pi), with their unique physical properties, can partly replace precious metal catalysts and hold great application potential. However, further modification is necessary to enhance their catalytic activity and stability. Therefore, this study prepared a coral-like cluster Co/Zn-Pi@NF (Pi represents phosphate) catalyst, which was grown in situ on nickel foam (NF) using the constant current electrodeposition method. The catalyst exhibited superior catalytic performance in 1 M KOH, with the required overpotentials for the hydrogen evolution reaction (HER) and OER reaching 10 mA·cm−2 being 36.6 mV and 343.4 mV, respectively. In 1 M KOH containing 0.5 M urea, the urea oxidation potential was only 1.4 V, which remained stable for 60 hours. The Co/Zn-Pi@NF nanoparticles were used as the anode and cathode for water-urea electrolysis, and the electrolysis voltage was 1.43 V at a current density of 10 mA·cm−2, which was 290 mV lower than that of electrolyzed water. This study demonstrates that zinc-cobalt bimetallic phosphate can be used as a dual-function electrocatalyst for hydrogen evolution and urea oxidation.

Nanostructured bismuth phosphate-based asymmetric supercapacitor: electrochemical evaluation and oscillator application

Phosphate-based materials have received significant attention for various applications. In supercapacitors, metal phosphates exhibit high capacitance and superior rate performance. In this work, a wet chemical route was applied for the fabrication of aniline stabilized monoclinic bismuth phosphate (BPO) particles within the size range of 4–10 nm. The synthesized material was utilized as an active component for the application of a supercapacitor. The performances of the material were examined on a nickel foam for a three-electrode electrochemical cell. The material showed the maximum specific capacitance (CSP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${C}_{SP}$$\\end{document}) value of 255 F.g−1 at the current density (CD) of 2 A.g−1. Further, an asymmetric supercapacitor (ASC) device was fabricated with BPO and single wall carbon nanotube (SWCNT) as negative and positive electrodes, respectively, which delivered a specific capacity (Qs)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(Qs)$$\\end{document} value of 1462 mAh.g−1 under the CD of 0.4 A.g−1 with the energy density (ED) and power density (PD) values of 2.2 Wh.kg−1 and 0.68 kW.kg−1, respectively. The device exhibited capacity retention and coulombic efficiency (CE) values of 84 and 95% at 0.9 A.g−1 for 10,000 galvanostatic charge–discharge (GCD) cycles. The ASC device generated a low-frequency waveform and has the potential to function as an oscillator.

Enhanced oxygen evolution reaction performance using amorphous hollow cerium-doped cobalt phosphate derived from ZIF-67 structures

A major obstacle in achieving massive operations water splitting is the slow rate of the anodic reaction. To address this issue, metal phosphates have been extensively employed as efficient materials for the oxygen evolution reaction (OER). In this study, ZIF-67 structures were synthesized in both single-metal and bimetallic forms with different molar ratios of cerium. The structure with the best electrochemical activity ((5 present) cerium doped ZIF-67 ((5)CeZIF-67)) was subjected to a phosphatization process, resulting in the formation of the amorphous and hollow cerium doped cobalt phosphate (Ce-CPO) structure as a novel and highly efficient OER electrocatalyst. To the best of authors knowledge, this is the first report on the synthesis and application of Ce-CPO structure for boosting OER process. This resultant structure exhibited suitable electrochemical performance in the oxygen evolution reaction (OER), achieving an overpotential of 286 mV at a current density of 30 mA cm−2 and a Tafel slope of 74.4 mV decade−1. Furthermore, the final structure demonstrated satisfactory stability during a 10 h operation period. The notable improvement in the Ce-CPO structure was due to the use of a bimetallic framework combined with phosphorus and an amorphous porous structure. The distinctive configuration achieved greatly amplifies the effective surface area, hence improving electron transfer. The findings of this research can contribute to the development of electrodes with improved performance in OER.

Recent Advances in Metal Oxide and Phosphate Nanomaterials Radiolabeling with Medicinal Nuclides.

The utilization of nanomaterials in biomedical applications has surged in recent years; yet, the transition from research to practical implementation remains a great challenge. However, a promising area of research has emerged with the integration of nanomaterials with diagnostic and therapeutic radionuclides. In this Review, we elucidate the motivations behind selecting metal oxide- and phosphate-based nanomaterials in conjunction with these radionuclides, while addressing its issues and limitations. Various metal oxide- and phosphate-based nanoparticles, exhibiting low toxicity and high tolerability, have been proposed for diverse biomedical applications, ranging from bone substitutes to drug delivery systems and controlled release vectors for pharmaceuticals, including radionuclides for nuclear medicine imaging and therapy. Moreover, the potential synergistic effects of multimodal combinational therapies, integrating chemotherapeutics, immunomodulators, or hyperthermia, underscore the versatility of these nanoconstructs. Our comprehensive exploration includes the underlying principles of radiolabeling strategies, the pivotal attributes of nanomaterial platforms, and their applications. Through this perspective, we present the potential of nanotechnology-enabled nuclear medicine. Furthermore, we discuss the potential systemic and local applications of these nanoconstructs, considering their in vitro and in vivo characteristics, as well as their physicochemical properties.

Rapid electrodeposition synthesis of partially phosphorylated cobalt iron phosphate for application in seawater overall electrolysis

To obtain hydrogen energy from seawater, it is of utmost importance to design an efficient bifunctional electrocatalyst that can be produced on a large scale and in a rapid manner. In this work, iron cobalt phosphate (CoFe-EP/NF) for long-term efficient and stable seawater electrolysis were rapidly synthesized by a simple electrodeposition. The study showed that metal phosphides/phosphates provided additional active sites for the catalysts for hydrogen evolution reaction (HER, 160 mV at 100 mA/cm2) and oxygen evolution reaction (OER, 266 mV at 100 mA/cm2), in alkaline seawater electrolyte (1 M KOH + seawater), respectively. Notably, the presence of phosphate groups facilitates the transformation of cobalt-iron metal phosphates into the truly reactive substance CoOOH, which improves the OER kinetics. In addition, the phosphate layer formed after catalyst activation avoids the occurrence of chlorine evolution reaction (CER) by shielding the adsorption of Cl−, thus enhancing the corrosion resistance and enabling long-term stable operation in seawater. The two-electrode overall seawater electrolysis easily reaches 100 mA/cm2 at 1.68 V and exhibit a long-term durability of more than 100 h. This study offers a viable approach for the synthesis of electrocatalysts with high activity and corrosion resistance, which is vital for the practical realization of large-scale seawater electrolysis.

A transparent, anti‐blue‐light, and high strength nylon/nickel phosphate oligomer nanocomposite formed via intermolecular hydrogen bond crosslinking

AbstractPolymer/transition metal inorganic salts nanocomposites are promising engineering materials in automotive, electronics, aerospace and smart wearables fields. However, the interfacial incompatibility always causes agglomeration and phase separation, constraining their further application. Inspired by inorganic oligomers' polymerization, nylon/nickel phosphate oligomer (NPO) nanocomposite (ENCC) was prepared via hydrogen bond crosslinking method. Due to the formation of hydrogen bonds between PO43− end groups of NPO with an average diameter of 6.5 ± 1.2 nm and NH groups on the nylon molecular chain, the phase compatibility is greatly improved. Hence, NPO was uniformly nano‐dispersed and had no obvious agglomerate in ENCC, inducing an invisible phase interface at nano‐micro scale. Nylon/nickel phosphate oligomer showed an excellent reinforcing effect on nylon, the tensile strength and elongation of ENCC reached 28 ± 0.8 MPa and 585 ± 26% at a high loading of 20 wt%, increased by 155% and 92%, compared with pure matrix, respectively. Furthermore, ENCC was still optically transparent and had excellent anti‐blue‐light performance (up to 96.6%).Highlights Novel inorganic/nylon composite prepared by hydrogen bond crosslinking method. Phase separation and aggregation problems were solved remarkably. Inorganic metal phosphate dispersed with a diameter of 6.5 ± 1.2 nm. The composite was still transparent at 20 wt% loading of metal phosphate. Tensile strength and elongation increased by 155% and 92%, respectively.

Efficient and eco-friendly carbon dioxide capture with metal phosphate catalysts in monoethanolamine solutions

Efficient and eco-friendly carbon dioxide capture with metal phosphate catalysts in monoethanolamine solutions

Catalytic hydrodeoxygenation of lignin-derived phenolic compounds with Ni-based aluminum phosphate catalyst

Lignin-derived products possess high carbon content and offer significant potential to be used as liquid fuels. However, they also contain high oxygen element and unstable functional groups. Hydrodeoxygenation (HDO) is an effective method for upgrading lignin-derived phenolic compounds to produce high-quality liquid biofuels. In this study, a series of Ni-based phosphate catalysts incorporating various metals (Al, Ce, La) were prepared and employed for the HDO of lignin-derived phenolic compounds. The results showed that Ni/AlPO4 had the most efficient HDO performance, with guaiacol conversion of 99.9 % and cyclohexane selectivity of 91.1 % at the reaction temperature of 250 °C. Various catalyst characterization measurements were conducted to assess the impact of metal phosphate species on the crystallography, morphology, physicochemical characteristics and surface properties. Results indicated that Ni/AlPO4 catalyst exhibited stronger acidity, smaller Ni particle sizes and larger specific surface area than other Ni-based phosphate catalysts. Based on the characterization results and experimental data, the corresponding HDO reaction pathways and mechanisms were also proposed. Ni/AlPO4 catalyst was also applied to the HDO of various lignin-derived phenol compounds and achieved a good HDO effect. Moreover, the catalytic upgrading of lignin-oil was also carried out, and a high proportion of hydrocarbon products that increased from 16.0 % to 88.6 % was obtained. This Ni/AlPO4 catalyst provides potential reference for the HDO application of lignin-derived phenolic compounds for the production of hydrocarbon liquid fuels.

Development of Fe-Doped Ni2P-POx Electrocatalyst for Oxygen Evolution Reaction

Water electrolysis is extensively researched as a next-generation energy storage method to overcome the intermittency of renewable energy. Electricity generated from renewable sources such as solar and wind power can be converted into pure green hydrogen through water electrolysis. Despite the potential of green hydrogen as a renewable energy storage/carrier medium, the high overpotential resulting from the slow kinetics of oxygen evolution reaction (OER) and the use of expensive noble metals make cost-competitive hydrogen production a significant challenge. Anion exchange membrane water electrolysis (AEMWE) is one method for hydrogen production, offering economic advantages over proton exchange membrane systems as it allows for the use of relatively inexpensive transition metal catalysts like Ni, Fe, and Co due to its alkaline environment.Nickel phosphide (Ni2P)-based catalysts have emerged as highly promising candidates to accelerate the electrocatalytic OER. In particular, the introduction of Fe into Ni2P has been found to induce charge transfer, optimizing the electronic structure and accelerating the OER process. OER catalysts based on transition metal phosphides often exhibit a core-shell structure with phosphide at the core and oxide at the shell during OER measurements. This core-shell structure enhances OER performance through the oxide shell, complementing the deficient electrical conductivity of the phosphide core, resulting in superior catalytic activity and durability. From this perspective, transition metal phosphates are also being studied as electrocatalysts for OER. Phosphates, such as PO3 -, not only promote oxygen adsorbate adsorption but also induce a distorted local metal center geometry that favors OH- adsorption and further oxidation.To address these challenges, this study develops a facile and scalable synthesis of iron-doped nickel phosphide-phosphate (Fe-doped Ni2P-POx) nano-hybrid system as a superior noble-metal free OER powder-catalyst. The utilization of self-filling and pyrolysis approaches facilitates economically viable production of the highly porous phosphide catalyst with a high specific surface area and rough surfaces. X-ray diffractometer, X-ray photoelectron spectroscopy, and electron paramagnetic resonance elucidates the electronic structure modulation, resulting in phosphide-phosphate nano-hybrid structures. Consequently, the catalyst demonstrates excellent OER activity in 1 M KOH, with a significantly low overpotential of 283 mV at 20 mA cm-2, a small Tafel slope of 28.4 mV dec-1, and a superior exchange current density of 8.22 mA cm-2, surpassing state-of-the-art PGM catalysts. Furthermore, its durability over 20 hours indicates its excellent stability, mass transport properties, and mechanical robustness in alkaline media, underscoring its potential as an efficient OER catalyst to facilitate electrocatalytic hydrogen production. Figure 1

Surface and composition effects on the biphasic cytotoxicity of nanocomposites synthesized using leaf extracts

The Malus sylvestris L. (LE1), Pinus sylvestris L. (LE2), and Sorbus aucuparia L. (LE3) leaves` extracts were used for the synthesis of silver (Ag) nanocomposites containing different amounts of silver chloride (AgCl), silver metal (Agmet), and silver phosphate (Ag3PO4). These nanocomposites were capped with the organic functional groups in the leaf extract. Notably, the nanocomposites caused biphasic cytotoxic response on cells; first attributed to the inhibition of cell growth and second to cell death. The nanocomposites were biocompatible with normal embryonic kidney (HEK293) cells in the cytotoxic range for cancer cells. ▪ [25(±1) °C synthesis] nanocomposites exhibited the highest cytotoxicity towards HeLa (lethal concentration- LC50 value of 11.4 μg mL−1) and A549 (LC50 value of 14.7 μg mL−1) after 24-h incubation and its efficiency was shown also for the more resistant MCF-7 and MDA-MB-231, however, their respective LC50 values were larger. For the HeLa cell line, this designed ▪ nanocomposite exhibited an LC50 value similar to the effective concentration (EC50) value of Cisplatin and about 3 times larger than Doxorubicin. ▪ nanocomposite contained Ag3PO4 in the composite and P on the surface, higher AgCl content, smaller crystallite size of all nanoparticle phases, and carbon-rich oxygen-deficient surface compared to all other nanocomposites.

НЕКОТОРЫЕ ОСОБЕННОСТИ РАЗРАБОТКИ ФОРМОВОЧНЫХ И СТЕРЖНЕВЫХ СМЕСЕЙ С ПРИМЕНЕНИЕМ БОРАТФОСФАТНЫХ СВЯЗУЮЩИХ

In the practice of foundry production, it is known to use cores of phosphate cold-hardening mixtures (CMC), containing: aluminophosphate (APS), magnesium phosphate (MFS), aluminochrome phosphate (ACPS), magnesium aluminophosphate (MAPS), calcium magnesium phosphate (CMPS), chromophosphate (CPS) and boraluminophosphate (BAPS) and other binders [1-20]. The widespread use of metal phosphate binders (MPBs) is hampered by the fact that CBTs made on their basis have a number of disadvantages. In particular, cold-hardening mixtures prepared using an aluminophosphate binder (APB) and a magnesium phosphate binder (MPB) do not provide the mixtures with sufficient binding and strength properties. Regulation of such properties of molding and core mixtures as survivability, formability, crumbling, strength and some other properties occurs by changing the composition and content of binder compositions in the mixtures. It is known that boric acid and its salts exhibit adhesive-cohesive properties and the use of which as a modifier in the composition of thermal insulation, molding, and core mixtures improves their physical, mechanical and technological characteristics. It is also known that boric acid enters into chemical reactions with inorganic and organic substances to form complex compounds that exhibit more pronounced binding properties than boric acid. The purpose of the work is to improve the properties of aluminophosphate and magnesium phosphate cold-hardening mixtures using boric acid (H3BO3), borophosphoric acid (composition H3BO3•H3PO4) and borophosphorous acid (composition H3BO3•H3PO3) and their effect on the strength characteristics, crumbling and formability of the tested mixtures.

Electronic structure and delithiation mechanism of vanadium and nickel doped Li2MnPO4F cathode material for lithium-ion batteries

This study calculates the energy band structure and density of states of Lithium manganese fluorophosphate (Li2MnPO4F, a lithium transition metal phosphate compounds) using the first-principles plane-wave pseudopotential approach within the density-functional theory. The model of Li2M0.5Mn0.5PO4F (M = V, Ni) with transition metal doped Mn sites is constructed by using the CASTEP module. The calculation findings indicate that the transition metal doping can regulate the energy band structure of the intrinsic system, and Li2MnPO4F makes the band gap decrease, and the volume increase with the Li ions of being deintercalated, and the electrons can be readily stimulated from the valence band to the conduction band. The findings indicate that Li2MnPO4F is a favorable cathode material for high-voltage lithium ion batteries (LIBs). The introduction of vanadium (V) and nickel (Ni) doping reduces the band gap, facilitating an easier excitation of electrons from the valence band to the conduction band. This study provides a theoretical study of new cathode materials for high performance LIBs.

Adsorption of Glyphosate in Water Using Iron-Based Water Treatment Residuals Derived from Drinking Water Treatment Plants

Glyphosate, a broad-spectrum herbicide, poses a potential threat to human health and the ecosystem due to its toxicity. In this study, iron-based water treatment residuals (Fe-WTRs) were employed for glyphosate removal. The adsorption kinetics, isotherms, and thermodynamics, as well as the effects of pH, Fe-WTR particle size, and temperature, were explored. The results show that Fe-WTRs are an effective adsorbent for glyphosate adsorption, and the maximum uptake capacity was recorded as 30.25 mg/g. The Fe-WTR surface was positively charged, and low-valent iron dominated under acidic conditions, favoring glyphosate adsorption. Furthermore, smaller Fe-WTR particles (<0.125 mm) showed a faster absorption rate and 20% higher adsorption capacity than larger particles (2–5 mm). The kinetic analysis indicated that the adsorption process exhibits a two-step profile, conforming to the pseudo-second-order model, and the thermodynamic analysis indicated that it is a spontaneous, endothermic, and entropy-driven reaction. Finally, the Fourier transform infrared spectral analysis revealed that this process is mainly associated with the formation of metal phosphate through the ligand exchange of the phosphate groups of glyphosates with the hydroxyl groups of iron present in Fe-WTRs. In this study, we demonstrated the potential of Fe-WTRs as a cost-effective and efficient adsorbent for glyphosate removal.

Characterizing the Stoichiometry of Individual Metal Sulfide and Phosphate Colloids in Soils, Sediments, and Industrial Processes by Inductively Coupled Plasma Time-of-Flight Mass Spectrometry.

Size and purity of metal phosphate and metal sulfide colloids can control the solubility, persistence, and bioavailability of metals in environmental systems. Despite their importance, methods for detecting and characterizing the diversity in the elemental composition of these colloids in complex matrices are missing. Here, we develop a single-particle inductively coupled plasma time-of-flight mass spectrometry (sp-icpTOF-MS) approach to characterize the elemental compositions of individual metal phosphate and sulfide colloids extracted from complex matrices. The stoichiometry was accurately determined for particles of known composition with an equivalent spherical diameter of ≥∼200 nm. Assisted by machine learning (ML), the new method could distinguish particles of the copper sulfides covellite (CuS), chalcocite (Cu2S), and chalcopyrite particles (CuFeS2) with 75% (for Cu2S) to 99% (for CuFeS2) accuracy. Application of the sp-icpTOF-MS method to particles recovered from natural samples revealed that iron sulfide (FeS) particles in lake sediment contained ∼4% copper and zinc impurities, whereas pure pyrite (FeS2) was identified in hydraulic fracturing wastewater and confirmed by selected area electron diffraction. Colloidal mercury in an offshore marine sediment was present as pure mercury sulfide (HgS), whereas geogenic HgS recovered from an industrial process contained ∼0.08 wt % silver per Hg, enabling source apportionment of these colloids using ML. X-ray absorption spectroscopy confirmed that Hg was predominantly present as metacinnabar (β-HgS) in the industrial process sample. The determination of impurities in individual colloids, such as zinc and copper in FeS, and silver in HgS may enable improved assessment of their origin, reactivity, and bioavailability potential.

Unraveling catalytic conversion of spent coffee grounds through alkaline and alkaline earth metal phosphates in hydrothermal carbonization

Hydrothermal carbonization (HTC) offers a promising pathway for sustainable energy production, with spent coffee grounds (CG) emerging as an eco-friendly feedstock for hydrochar generation. However, the potential applications of alkaline and alkaline earth metal phosphates as catalysts for novel carbonaceous materials remain largely unexplored. This study investigates the impact of alkaline types on the characteristics, morphology, and heating value of hydrochar derived from CG. Incorporating Mg3(PO4)2, K3PO4, and Na3PO4 into HTC processes resulted in significant reductions in carbon content, leading to decreased hydrochar yield, higher heating value (HHV), and energy yield (EY). Notably, HHV reduction ranged from 2 % to 15 %, depending on catalyst type and temperature. The catalysts contributed to increasing ash content in hydrochar due to their inorganic nature. The presence of catalysts minimally impacted the hydrochar surface functional groups, with a more amorphous structure observed at 200 °C across all samples. A higher abundance of microspheres was observed in hydrochar catalyzed by K3PO4 and Na3PO4 at 200 °C compared to Mg3(PO4)2. Interestingly, K3PO4 and Na3PO4 reduced nitrogen content of the hydrochar rather than Mg3(PO4)2. The proposed catalytic mechanism involved metal phosphate catalyzing hydrolysis reactions, thereby reducing hydrochar yields while augmenting volatile fatty acid (VFA) and furan contents in the process water. Alkaline and alkaline earth metal phosphates catalysts exhibited trade-offs between hydrochar properties and hydrolysis byproducts in the HTC of CG.

Catalytic decomposition of HFC-134a over metal oxide and phosphate catalysts to VDF: Reaction pathways of CH4 addition

HFC-134a refrigerants are commonly used in air-conditioners and refrigerators. HFC-134a has a GWP 1,430 times higher than that of CO2 and contributes significantly to climate change. Therefore, research has been conducted to eliminate HFC-134a via catalytic decomposition. The catalytic decomposition of HFC-134a with the addition of CH4 over metal oxide (CaO, MgO, and Al2O3) and phosphate catalysts (Ca2P2O7, Mg2P2O7, and AlPO4) is described herein. The prepared catalysts were characterized by NH3-TPD, TGA, and BET analysis. Metal phosphate catalysts exhibited higher HF resistance than metal oxide catalysts. XRD, XRF, and SEM-EDS confirmed the superior resistance of metal phosphates to corrosive hydrogen fluoride (HF). VDF (C2H2F2) is a valuable feed product that can be polymerized into polyvinylidene fluoride (PVDF). In addition, the VDF yield increased with CH4 addition during the HFC-134a decomposition reaction. The CaP-calcium phosphate-catalysts exhibited an efficiency of more than 80 % and the highest VDF yield of 28.8 % after 10 h at 900 °C, 1 bar, and HFC-134a:CH4:N2 = 1:2:17 and RT = 1.0. The introduced CH4 feed acts as a CH3 donor during the decomposition of HFC-134a. Consequently, a comprehensive mechanism of VDF synthesis was proposed by comparing the presence of CH4 feed.

Electrochemically Induced Deposition (ECiD): A Versatile Method that Greatly Extends the Portfolio of Surface Coatings and Materials Fabricated by Electrochemical Deposition

Electrochemically induced deposition or ECiD can be defined as the deposition of compound films on a surface, as the result of chemical reactions in the near surface region between a precursor present in the bulk solution and an electrochemically generated precursor, mediator, or catalyst near that surface. The ECiD process has evolved from an odd curiosity into a thriving new branch in electrodeposition science. The library of materials synthesized by ECiD has been greatly expanded, along with the number of precipitation triggering knobs or tricks. Together with the breadth of possibilities and applications, the science behind the process has also accelerated. This article introduces the principle of the ECiD process for the electrodeposition of oxides, hydroxides, and compounds such as metal phosphates and metal-organic frameworks. The article discusses the mechanisms of these electrochemically induced deposition reactions as well as the pro-bases used to trigger the deposition.

Experimental and theoretical studies on cobalt ruthenium phosphate structure optimization towards supercapacitor application

Recent studies have given indications that nanoarchitectured binary transition metal phosphates can act as potential supercapacitor (SC) electrode materials due to their exceptional energy storage capacity and remarkable electrochemical stability. However, the highly amorphous nature or broad X-ray diffraction peaks of metal phosphates put a limit on the structural optimization of these materials. We demonstrate a combined experimental and theoretical study leading to an optimized cobalt-ruthenium phosphate (CRP) structure for high-performance SC application. The material structure was optimized by detailed density functional theory (DFT) calculations, including the Bader charge analysis, DOS, and PDOS, revealed the lattice and volume expansion, reduced band gap, and improved conductivity of the cobalt phosphate lattice by including ruthenium in the cobalt phosphate. These predictions are verified with experimental band gap and high-resolution transmission electron microscope plane image indexing. Further, the CRP was developed by potentiostatic deposition onto the carbon cloth substrate. The flexible CRP electrode exhibited a high specific capacitance of 1258 F g−1 (943.5C g−1) in the aqueous 2 M KOH electrolyte. The asymmetric SC device (CRP//activated carbon) has exhibited an excellent specific energy of ∼59 Wh kg−1 at a specific power of ∼751 W kg−1.