Inexpensive Metal Research Articles

Interfacial coupling of sea urchin-like (Mo4O11-MoS2-VO2) promoted electron redistributions for significantly boosted hydrogen evolution reaction

Developing efficient electrocatalysts for hydrogen evolution reaction (HER) is of great importance in contemporary water electrolysis technology. Here, a novel hierarchically sea urchin-like electrocatalyst (Mo4O11-MoS2-VO2) is synthesized by hydrothermal deposition and post-annealing strategy. The optimized electrocatalyst behaves as a high active hydrogen evolution electrode in 0.5 mol/L H2SO4. This electrode needs overpotential of only 43 mV to achieve 10 mA/cm2 with a Tafel slope of 37 mV/dec and maintains its catalytic activity for at least 36 h. Better than most previously reported non-noble metal electrocatalysts anchored on carbon cloth. It is worth mentioning that the hierarchical sea urchin-like structure promotes the redistribution of electrons and provides more catalytic active sites. This strategy shows a way for the construction of inexpensive non-noble metal electrocatalysts in the future.

Carbon nanoparticle-entrapped macroporous Mn3O4 microsphere anodes with improved cycling stability for Li-ion batteries

Manganese oxide (Mn3O4) has garnered substantial attention as a low-cost, environment-friendly anode material. It undergoes a conversion reaction involving the formation of Li2O and metallic Mn to provide high-energy Li-ion batteries. However, its low electrical conductivity and significant volume change reduce its capacity during the initial lithiation/delithiation, hindering its practical application. To improve the cycle performance, we propose a new composite structure wherein we entrap carbon nanoparticles in macroporous Mn3O4 microspheres with a unique maze-like porous interior. We fabricate the Mn3O4/C composites using a scalable two-step process involving the thermal decomposition of MnCO3 in water vapor and mixing in a carbon-dispersed solution. The fabricated Mn3O4/C composites with varying carbon contents exhibit a high maximum discharge capacity retention of 86% after 50 cycles, compared to the 18% given by bare Mn3O4. The entrapped carbon nanoparticles improve the cycle performance both electrochemically and physically. The microstructure of the composite particles and the fabrication process developed in this study will help improve the performance of other conversion-type anode materials that suffer from cycle degradation, including inexpensive transition metal oxides and sulfides.

Ionomer Distribution Strategy of Anion Exchange Membrane Fuel Cell Catalyst Layer in Terms of Interaction between Catalyst Slurry Components

Anion exchange membrane fuel cells (AEMFCs) have been intensively studied in recent years to replace proton exchange membrane fuel cells (PEMFCs). The acid-to-alkali transitions have the potential to lower overall system costs because it allows the non-precious metal catalysts and inexpensive metal stack hardware. Significant strides have been made in materials science in the last few decades, particularly the development of high IEC-containing anion exchange membrane (AEM) and ionomer (AEI) possessing high OH- conductivity, enabling comparable cell performance to that of PEMFC. In addition, the discovery of high HOR activity of PtRu by oxophilic and/or electronic effects, and reducing ionomer poisoning, provided an opportunity to further advance the cell performance of AEMFC. However, despite the remarkable development of materials, modest AEMFCs still have inadequate power performance (< 0.5 W cm-2) even using the precious catalysts, which stems from a lack of understanding of the catalyst layer (CL) design.CL consists of a catalyst and an ionomer, where the chemical energy of the fuel is converted into electrical energy in triple-phase-boundaries (TPBs). TPB is an electrochemically active site where catalyst (electrons), ionomer (H+ or OH-), and reactant gases were concurrent. In order to realize a high-performance fuel cell, the TPB should be high enough to utilize the capabilities of the catalyst, and the ideal state would be to maximize the contact area between the ionomer and the catalyst while minimizing the loss of CL porosity. Accordingly, the structure of the CL is one of the key factors that directly affect the performance of the fuel cell and is in great account.CL is fabricated from a slurry containing a catalyst, ionomer, and dispersing solvent, whose structure is determined by the complex interactions between slurry components. Therefore, fine-tuning of comprehensive interaction (catalyst/ionomer, catalyst/solvent, and ionomer/solvent) is the core technology in CL design, and an in-depth understanding of each interaction is also essential. In this regard, we recently presented the rational design of the CL by controlling AEI size, distribution via a solvent selection of the catalyst slurry. Specifically, the larger the solubility parameter (excluding the hydrogen bonding term) of the organic solvent mixed with water, the smaller the dispersed AEI size, leading to an even distribution of the AEI in the CL. This induces a high electrochemical surface area of the CL, making it possible to achieve high performance AEMFC from the low current region. However, nevertheless, we found that the distribution of AEI in the AEMFC catalyst layer was still not completely uniform through various types of electron microscopy analysis. In particular, when the morphology of the AEMFC CL was compared with the Nafion ionomer (commonly used in PEMFC field) as a reference, AEI caused lower porosity by clogging the pores of Pt/C nanoparticles. For this reason, we found that AEMFCs had lower performance than Nafion-based PEMFCs, despite their high ORR activity under alkaline conditions.Molecular dynamics (MD) and density functional theory (DFT) simulation analyzes show that AEI has a particularly low interaction with carbon compared to Nafion, and for this reason, we found that AEI aggregates with each other rather than evenly distributed on the Pt/C surface. We used QPC-TMA as AEI in this study and confirmed that commercialized AEI (FAA-3 and XA-9) also form low CL porosity and pore-closing characteristics. This result suggests that low interaction between AEI/carbon is a universal property of current levels of AEI. Therefore, when designing an ionomer to improve the performance of AEMFC, high interaction with carbon should be considered as another important variable.

The High Electrocatalytic Performance of NiFeSe/CFP for Hydrogen Evolution Reaction Derived from a Prussian Blue Analogue

Non-noble-metal-based chalcogenides are promising candidates for hydrogen evolution reaction (HER) by harnessing the architectural design and the synergistic effect between the elements. Herein, a porous bimetallic selenide (NiFeSe) nanocube deposited on carbon fiber paper (NiFeSe/CFP) was synthesized through a facile selenization reaction based on Prussian blue analogues (PBAs) as precursors. The NiFeSe/CFP exhibited excellent HER activity with an overpotential of just 186 mV for a current density of 10 mA cm−2 in 1.0 M KOH at ambient temperature, similar to most of the state-of-the-art transition metal chalcogenides. The corresponding Tafel slope was calculated to be 52 mV dec−1, indicating fast discharge of the proton during the HER. Furthermore, the catalyst could endure long-term catalytic tests and showed remarkable durability. The enhanced electrocatalytic performance of NiFeSe/CFP is attributed to the unique 3D porous configuration inherited from the PBA templates, enhanced charge transfer occurring at the heterogeneous interface due to the synergistic effect between the bimetallic phases, and the high conductivity improved by the formation of amorphous carbon shells during the selenization. These findings prove that the combination of inexpensive metal–organic framework precursors and hybrid metallic compounds is a feasible way to realize the performance enhancement of non-noble-metal-based chalcogenides towards alkaline HER.

Substrate-controlled selective acylation of quinazolinones: Access to 2-benzamido-N-formylbenzamides and 3-benzoylquinazolinones

A substrate-controlled selective reaction has been developed for the acylation of the N1 atom of quinazolinones with aldehydes to prepare 2-benzamido-N-formylbenzamide and 3-benzoylquinazolinone derivatives. This reaction proceeds smoothly under inexpensive metal catalysis, which gives rapid access to a variety of 2-benzamido-N-formylbenzamides and 3-benzoylquinazolinones in moderate to excellent yields. This reaction can be applied to a variety of quinazolinones and aldehydes with excellent selectivity.

Nickel and Copper Catalyzed ipso-Phosphonodifluoromethylation of Arylboronic Acids with BrCF2 P(O)(OEt)2 for the Synthesis of Phosphonodifluoromethylarenes.

A convenient method for the direct ipso‐phosphonodifluoromethylation of arylboronic acids via nickel‐copper co‐catalysis is disclosed. This work, which utilizes inexpensive first row transition metals, represents a facile alternative to the traditional palladium catalyzed approach. The method utilizes inexpensive commodity chemicals and substrates while tolerating a variety of biologically relevant functional groups. Structurally diverse phosphonodifluoromethylarenes are furnished in good yields under short reaction times. Control experiments to probe possible reaction pathways are also included.

Development of highly alkaline stable anion conductive polymers with fluorene backbone for water electrolysis

AbstractAnion exchange membrane water electrolysis (AEMWE) is currently paying attention as a new hydrogen (H2) production method since it can operate at high current densities using inexpensive nonnoble metal catalysts. However, the significant problems of AEMs, including their insufficient anion conductivity and alkaline stability, prevent the practical usage of AEMWE. We show a novel anion conductive polymer, alkyl trimethylammonium‐substituted polyfluorene (TMA‐PF), bearing no heteroatom bonds in the main chain. The TMA‐PF membrane possesses higher anion conductivity than conventional AEMs due to the increased flexibility and mobility of the alkylammonium side chains of TMA‐PF. The TMA‐PF membrane shows high‐alkaline stability and maintains the initial ion conductivity after immersion in an aqueous NaOH solution (8 mol L−1) at 80°C for 48 h. In the water electrolysis evaluation, the cell using the TMA‐PF membrane exhibits a higher current density (400 mA cm−2 at 2.03 V) than the cell using the conventional AEM at the same potential, indicating that the novel AEM has a high potential to generate H2 effectively. Green hydrogen produced by AEMWE using renewable energy will be an environmentally benign energy source without CO2 emissions.

BIAN-Aluminium-Catalysed Imine Hydrogenation.

Hydrogenations have been dominated by transition metal catalysis, while the use of more abundant and inexpensive main group metal catalysts has remained a great challenge. Here, a bimetallic Li/Al dihydride was successfully applied to catalytic hydrogenations of imines. The catalyst [(DippBIAN)Al(μ‐H)2Li(OEt2)2] was easily prepared from the 2e‐reduced BIAN derivative and LiAlH4.

Binary spindle-like cobalt–iron layered-double hydroxide as an efficient electrocatalyst for oxygen evaluation reaction

In this research, inexpensive transition metals are used for electrocatalytic oxygen evolution reactions. Nickel foam was modified as a substrate using spindle-like Co–Fe LDH. XRD, FE-SEM, EDS, and elemental mapping techniques are used for characterization. Based on LSV results, overpotentials of 280 and 355 mV were obtained at 10 and 100 mA cm−2, respectively. To evaluate the stability of electrocatalyst, cyclic voltammetry, chronoamperometry (at constant potentials of 1.55 and 1.65 V vs. RHE), and chronopotentiometry (at applied current densities of 10 and 100 mA cm−2) methods are used. All stability tests were performed consecutively using one electrode. Current density increased by 0.05% after performing 500 CV cycles. The catalytic performance was enhanced during the chronoamperometry analysis. However, the potential decreased slightly by less than 0.44% after 7200 s at 100 mA cm−2 in chronopotentiometry analysis. The high durability and current density ensure the efficient performance of the as-prepared electrocatalyst in water splitting process.

In-situ porous flake heterostructured NiCoP/Ni foam as electrocatalyst for hydrogen evolution reaction

It is critical to produce highly efficient, inexpensive and long-term durability non-noble metal catalysts for hydrogen production by water electrolysis on basis of renewable energy. In this study, the porous flake heterostructured NiCoP grown directly on porous networked Ni foam (NiCoP/NF) was obtained by the hydrothermal and phosphating method. As electrocatalysts for hydrogen evolution reaction (HER), the impact of Ni/Co ratios on NiCoP/NF catalytic performance was studied in 1.0 M KOH. Electrochemical measurement results display that the HER catalytic activity of NiCoP/NF increased first and then decreased with the decrease of Ni in the Ni/Co ratio. The NiCoP/NF1–3 catalyst (Ni/Co = 1:3) exhibited the highest performance for HER. A low overpotential of 99 mV at 10 mA cm−2 was achieved with the Tafel slope of 65.4 mV dec−1. In addition, porous flake heterostructured NiCoP/NF1–3 showed a good stability in alkaline condition, which maintained 20 h for stable water electrolysis at 10 mA cm−2. This present study will pave the way for the porous flake architecture development with high-performance HER in alkaline water electrolysis.

Recent Advances on Synthesis of CoCO3 with Controlled Morphologies.

Cobalt carbonates and derivatives represent most promising cost-effective materials for energy storage, conversion and upgrading. Morphology determines the performances, as size, shape and electronic configuration are key factors for tunable properties in the area of batteries, catalysis, magnetics and plasmonics. However, there is lack of insights in literature on morphological control of cobalt carbonates during hydrothermal and solvothermal conditions. Therefore, this review provides detailed discussion on synthesis, formation mechanism and morphological control of nanosheets, wires, spheres and cubes of cobalt carbonates. Furthermore, the influence of experimental conditions and plausible mechanism which govern the growing processes were further discussed in details. The outcome of this short review will offer insights into rational design of inexpensive metal carbonates for numerous other energy and environment applications.

Recent Advances in Catalytic Alkyne Transformation via Copper Carbene Intermediates.

As one of the abundant and inexpensive metals on the earth, copper has demonstrated broad applications in synthetic chemistry and catalysis. Among these copper-catalyzed advances, copper carbenes are versatile and reactive intermediates that can mediate a variety of transformations, which have attracted much attention in the past decades. The present review summarizes two different reaction models that take place between a copper carbene intermediate and alkyne species, including the cross-coupling reaction of copper carbene intermediate with terminal alkyne, and the addition of copper carbene intermediate onto the C–C triple bond. This article will cover the profile from 2010 to 2021 by placing emphasis on the detailed catalytic models and highlighting the synthetic applications offered by these practical and mild methods.

Nickel-cobalt phosphide terephthalic acid nano-heterojunction as excellent bifunctional electrocatalyst for overall water splitting

Recent research has focused on preparing excellent and inexpensive bifunctional transition metal electrocatalysts, which is challenging. Herein, a facile synthesis strategy for preparing self-supported nickel-cobalt phosphides using terephthalic acid (H2BDC) as metal-organic framework (MOF) precursor is reported. The incorporation of the MOF precursors modulated the electronic structures and improved the performance of the bimetallic transition metal phosphides with the as-prepared electrocatalyst requiring low overpotentials of 170 mV and 323 mV to reach 50 mAcm−2 for HER and OER, respectively. Moreover, the electrocatalyst is employed in an alkaline water electrolyzer and requires 1.57 V to attain a current density of 10 mAcm−2 with long-term stability, surpassing many reported MOF-derived bimetallic transition metal phosphide (TMPs) electrocatalysts. This work explores the incorporation of a rarely studied MOF precursor into self-supported bimetallic TMPs and opens the prospects of designing efficient MOF-derived electrocatalysts for overall water splitting.

Possible catalytic activity of N,N-coordinated mono-cationic copper bound Pyrazol-1-yl(1H-pyrrol-2-yl)methanone complex: a computational study

Organic ligand-based transition metal coordinated complexes have been of paramount importance. They have found a lot of utilities in catalysis, bond activation, dye-sensitized solar cells, etc. Focusing on the so-called noble metal or coinage metal and keeping in mind the inexpensive single metal atom based catalyst, copper bound complexes are considered for adsorption of gas molecules and bond activation therein. Here, we have studied the interaction between a [Cu–NN] complex (N,N-coordinated mono-cationic copper bound Pyrazol-1-yl(1H-pyrrol-2-yl)methanone) and different gas molecules as ligands, such as L = H2, N2, CO, H2O, C2H4 and C2H2, which are industrially and environmentally important. Our computational investigation infers that these ligands are effective in electronic interactions and optical properties of the complex. The stability, geometry and the bonding nature in L bound [Cu–NN] complexes are studied to check their viability at room temperature. The [Cu–NN] complex can bind small gas molecules as ligands, viz., H2, N2, CO, H2O, C2H4 and C2H2, in a thermodynamically favorable way and the complexation induces bond activation within the ligands in the bound state as compared to their free state. All the [L–Cu–NN] complexes along with the bare complex show broadband optical absorption in the ultraviolet–visible (UV–Vis) domains. Furthermore, selective ligand binding has modulated the Fermi energy level resulting in an enhanced chemical reactivity of the [Cu–NN] complex.

Theoretical investigation on electrocatalytic reduction of CO2 to methanol and methane by bimetallic atoms TM1/TM2-N@Gra (TM = Fe, Co, Ni, Cu)

Atom-dispersed catalysts such as single atom catalysts (SACs) and dual atom catalysts (DACs) can improve the atomic utilization and catalytic activity obviously in electrocatalytic CO2 reduction reaction (CO2RR). However, the current trial and error synthesis method of the catalysts is still the main experimental strategy, which consumes a lot of time and energy. Hence, we employed density functional theory (DFT) to design ten different transition metal DACs to compare and analyze the impact of electronic structures on their catalytic properties. Due to two metal atoms in DACs for adsorbing intermediates at the bridge site, it provides an unusual pathway for CO2RR to multi-electron reduction products, which helps formic acid to be further reduced as an intermediate rather than desorbed as a product. Among them, Fe/Co-N@Gra and Co2-N@Gra display better catalytic performance and product selectivity for methane with a low limiting potential (−0.37 V). This work investigates the CO2RR catalytic performance of inexpensive metal in atomic-level insights, which would be helpful for synthesizing catalysts efficiently with fewer experimental attempts.

Electrochemical synthesis of high entropy hydroxides and oxides boosted by hydrogen evolution reaction

Conventional synthesis techniques for high entropy materials often require prolonged processes or the use of complex fabrication steps. Here, we report on a scalable method to synthesize high entropy hydroxide and oxide nanoparticles using electrochemical synthesis in an aqueous environment. The current density parameter was set to create a non-equilibrium condition where the hydrogen evolution reaction results in a turbulent environment facilitating the formation of nanoparticles within the electrolyte. Using this approach, we demonstrate the synthesis of both binary (Fe, Mn) and quinary (Fe, Mn, Ni, Ca, Mg) metal hydroxide and oxide nanoparticles. The chemical and microscopy analysis shows that the high entropy nanoparticles can be synthesized as a hydroxide without any post processing and as an oxide through a calcination process with atomic scale mixing of all elements. The synthesis of high entropy nanoparticles is important for applications targeting catalysis, energy storage and conversion, filtration, and environmental engineering. • Aqueous electrochemical synthesis of high entropy hydroxides under ambient conditions • Green and substrate-free nanoparticle synthesis using inexpensive metal salts • Fast transformation from metal hydroxides to metal oxides with calcination process • Ability to scale to industrially promising applications Ritter et al. report an electrochemical process for quick and scalable synthesis of high entropy hydroxide and oxide nanoparticles that avoids long synthesis times and high temperatures. The large variety of metal salt precursors allows for tuning of the composition for applications in catalysis, energy storage, and conversion.

Industrial subsidies and impact on exports of trading partners: Case of China

AbstractThis paper explores the impact of Chinese subsidy interventions in the upstream sector on the competitiveness of the downstream sector. In particular, the paper investigates the causal effect of Chinese subsidies on base metal products on the export competitiveness of downstream sectors in other major trading countries. To explore the impact of base metal subsidy interventions on the downstream sector of a trading partner, we exploit both temporal variation in subsidy interventions and base‐metal consumption by the downstream sector. Using a panel data for 137 sectors in 40 major trading partners of the Chinese economy, the results of the paper reveal that a one‐unit increase in Chinese subsidies decreases competitors’ exports by an average of 16.6%. This indicates that an increase in one standard deviation of Chinese subsidies in the base metals sector decreases exports in the other major economies by 0.17 percentage points. The findings of the paper reveal that the impacts of Chinese subsidy interventions are larger and statistically significant for the exports of developed countries and metal‐intensive users in the downstream sectors. Production relocation to China, absorption of larger inexpensive base metals input by domestic Chinese firms, and subsidy complementarity in the Chinese upstream and downstream sectors could be some of the potential drivers for the negative impact of Chinese subsidy interventions on the export performance of foreign downstream firms.

Development and validation of UV chromatographic method for quantification of copper and copper nanoparticles in different matrices and pharmaceutical products

Background The applications of Cu and CuNPs based on the earth-abundant and inexpensive Cu metal have generated a great deal of interest in recent years, including medical applications. A novel, specific, precise, accurate and sensitive reverse-phase high-performance liquid chromatography (RP-HPLC) method with UV detection has been developed and validated to quantify copper (Cu) and copper nanoparticles (CuNPs) in different biological matrices and pharmaceutical products. Methods The developed method has been validated for linearity, precision, sensitivity, specificity and accuracy. Cu concentration was detected in pharmaceutical products without an extraction process. Moreover, liver, serum and muscle tissues were used as biological matrices. High Cu recovery in biological samples was afforded by using citric acid as a green chelating agent, exact extraction time and pH adjustment. Cu pharmaceutical and biological samples were eluted by acetonitrile: ammonium acetate (50 mM) with 0.5 mg/ml EDTA (30:70 v:v) as an isocratic mobile phase. EDTA reacted with Cu ions forming a Cu-EDTA coloured complex, separated through the C18 column and detected by UV at 310 nm. Results The developed method was specific with a short retention time of 4.95 min. It achieved high recovery from 100.3% to 109.9% in pharmaceutical samples and 96.8–105.7% in biological samples. The precision RSD percentage was less than two. The method was sensitive by achieving low detection limits (DL) and quantification limits (QL). Conclusion The validated method was efficient and economical for detecting Cu and CuNPs by readily available chemicals as EDTA and Citric acid with C18 column, which present the best results on RP-HPLC.

Application of Copper Nanoparticles in Dentistry.

Nanoparticles based on metal and metallic oxides have become a novel trend for dental applications. Metal nanoparticles are commonly used in dentistry for their exclusive shape-dependent properties, including their variable nano-sizes and forms, unique distribution, and large surface-area-to-volume ratio. These properties enhance the bio-physio-chemical functionalization, antimicrobial activity, and biocompatibility of the nanoparticles. Copper is an earth-abundant inexpensive metal, and its nanoparticle synthesis is cost effective. Copper nanoparticles readily intermix and bind with other metals, ceramics, and polymers, and they exhibit physiochemical stability in the compounds. Hence, copper nanoparticles are among the commonly used metal nanoparticles in dentistry. Copper nanoparticles have been used to enhance the physical and chemical properties of various dental materials, such as dental amalgam, restorative cements, adhesives, resins, endodontic-irrigation solutions, obturation materials, dental implants, and orthodontic archwires and brackets. The objective of this review is to provide an overview of copper nanoparticles and their applications in dentistry.

Theoretical study the influence of partial substitute noble metal Pd/Ag of PdAg-based catalyst by non-noble metal Ni/Cu for 1,3-Butadiene hydrogenation

Selective hydrogenation of 1,3-butadiene to form butene is an important tool for the removal of 1,3-butadiene which is a by-product of olefin production. AgPd bimetallic catalysts improved the butene selective, but its expensive cost is still an urgent problem. In this study, we introduced a third inexpensive metal Ni or Cu to replace part of the noble metal Pd or Ag in a common AgPd catalyst and studied the influence of the introduction on the hydrogenation reaction by DFT. Compared with the Ag3Pd and AgPd3 alloys, AgCuPd2 and Ag2NiPd hardly changed the adsorption energy of 1,3-butadiene and hydrogen but lowered the butene adsorption energy, which indicates that the addition of Cu or Ni metals can improve the butene selectivity. By calculating the reaction pathways, it was found that the energy barriers of 1,3-butadiene hydrogenation to butene on AgCuPd2 and Ag2NiPd was lower than that of Ag3Pd and AgPd3 alloys, while the energy barriers of butene further hydrogenation to butane was much larger than the desorption energy of butene. The partial replacement of Ag or Pd atom of AgPd alloys with Cu or Ni not only reduces the catalyst cost but also improves the conversion and selectivity of the hydrogenation reaction.