Synthesis Methods Of Materials Research Articles

A novel strategy of high oxygen vacancy concentration regulation for promoting the formation of nonradical species in the directional activation of peroxymonosulfate

In this study, a porous carbon catalyst (Co1(MgO)1/C) derived from the idea of “reducing metal element/irreducible oxides” was successfully synthesized, characterized and used to activate PMS for removing metronidazole (MNZ) from water. The Co1(MgO)1/C presented excellent catalytic performances on PMS activation for MNZ removal in a wide pH range and complex water environments. Various advanced characterization technologies and density functional theory (DFT) calculations indicated that Co1(MgO)1/C possessed a high concentration of oxygen vacancies (OV) (OV = 51.3%), which successfully induced the triple degradation pathway of MNZ in the Co1(MgO)1/C-PMS systems. Further analysis revealed that the triple MNZ degradation pathway was dominated by singlet oxygen, and supplemented by sulfate radical and electron transfer. Consequently, this study not only expands the existing synthesis methods for high-concentration OV materials but also provides new insights into the directional regulation of non-radical degradation pathways of pollutants.

Efficient electrocatalytic conversion of N2 to NH3 using oxygen-rich vacancy lithium niobate cubes

Instead of the energy-intensive Haber-Bosch process, the researchers proposed a way to produce ammonia using water and nitrogen as feedstock, powered by electricity, without polluting the environment. Nevertheless, how to design efficient electrocatalyst for electrocatalytic nitrogen reduction reaction (NRR) is still urgent and challenging. Herein, a strategy is proposed to adjust the morphology and surface electronic structure of electrocatalyst by optimizing material synthesis method. LiNbO3 (lithium niobate, LN) cubes with oxygen-rich vacancy and regular morphology were synthesized by hydrothermal synthesis and followed molten salt calcination process, which were used for electrocatalytic NRR under mild conditions. Compared with LN nanoparticles synthesized by solid phase reaction, LN cubes exhibit better NRR performance, with the highest ammonia yield rate (13.74 μg·h−1·mg−1) at the best potential of −0.45 V (vs. reversible hydrogen electrode, RHE) and the best Faradaic efficiency (85.43%) at −0.4 V. Moreover, LN cubes electrocatalyst also demonstrates high stability in 7 cycles and 18 h current–time tests. Further investigation of the reaction mechanism confirmed that the structure of oxygen vacancy could adjust the electronic structure of the electrocatalyst, which was conducive to the adsorption and activation of N2 molecule and also increased the ECSA of electrocatalyst, thus providing more active sites for the NRR process.

Constructing hierarchical structures of Pd catalysts to realize reaction pathway regulation of furfural hydroconversion

The technique of controlling nanoscale features precisely has been exploited to develop and improve bifunctional catalysts, which are important in the hydroconversion of furfural to high-value chemicals. Such bifunctional hydroconversion catalysts consist of metal sites and acid sites, and the intimacy extent of both active sites dictates the catalytic performance. In-depth exploration of the intimacy extent has been long limited by the lack of material synthesis and characterization method with nanometer precision. Herein, hierarchical catalytic structures with the spatial separation of Pd and acid sites were constructed by the multistep deposition strategy, wherein Pd was confined on defective CeO2 nanoclusters, which were dispersed on high-surface-area SiO2 with the strong acidity. The intimacy extent of Pd and acid sites in hierarchical catalytic structures of Pd/CeO2/SiO2 can be modulated by adjusting the CeO2 content, which leads to the aqueous-phase hydrogenation of furfural following a unique treble-site mechanism. The perpendicular adsorption of furfural on enriched oxygen vacancies of Pd/CeO2 contributes to the selective hydrogenation of the carbonyl group, and then the formed furfuryl alcohol undergoes the acid-catalyzed rearrangement of furan rings on SiO2 through the cooperative effect of acid sites and hydrogen spillover to give cyclopentanone. Meanwhile, the asynchronous catalysis effectively hinders the furan ring hydrogenation to tetrahydrofurfuryl alcohol by spatially separating Pd from the SiO2 surface. The superior catalytic performance is obtained on Pd/CeO2/SiO2-10 with a furfural conversion of 93% and cyclopentanone selectivity of 84%. We anticipate that the strategy of constructing hierarchical catalytic structures demonstrated here to spatially organize different active sites at the nanoscale will boost the further development of multifunctional catalysts.

Electrochemical Behavior of Morphology-Controlled Copper (II) Hydroxide Nitrate Nanostructures

Nanostructure control is an important issue when using electroactive materials in energy conversion and storage devices. In this study, we report various methods of synthesis of nanostructured copper (II) hydroxide nitrate (Cu2(OH)3NO3) with a layered hydroxide salt (LHS) structure using various synthesis methods and investigate the correlation between nanostructure, morphology, and their pseudocapacitive electrochemical behavior. The variations in nanostructure size and morphology were comprehensively explored by combining X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the electrochemical activity was characterized using cyclic voltammetry. We demonstrate that Cu2(OH)3NO3–LHS nanostructured submicron particles produced by alkaline precipitation with 88% of the copper cations can cycle with a two-electron redox process. Unfortunately, the electroactivity decreases rapidly from the first cycle due to the occurrence of structural transformations and subsequent electrochemical grinding. However, samples obtained by ultrasonication and microwave synthesis, two original synthesis methods for LHS materials, formed of nanosized crystalline domains agglomerated in micron-sized particles, represent a good compromise between capacity and cyclability. Moreover, by using pair distribution function analysis on electrode materials after repeated cycling, we were able to follow the chemical and structural changes occurring in Cu2(OH)3NO3 materials during electrochemical cycling with first a quick transformation to Cu2O and then the appearance of Cu metal and copper acetate Cu(II)2(O2CCH3)4·2H2O.

Active Site Engineering on Plasmonic Nanostructures for Efficient Photocatalysis.

Plasmonic nanostructures have shown immense potential in photocatalysis because of their distinct photochemical properties associated with tunable photoresponses and strong light-matter interactions. The introduction of highly active sites is essential to fully exploit the potential of plasmonic nanostructures in photocatalysis, considering the inferior intrinsic activities of typical plasmonic metals. This review focuses on active site-engineered plasmonic nanostructures with enhanced photocatalytic performance, wherein the active sites are classified into four types (i.e., metallic sites, defect sites, ligand-grafted sites, and interface sites). The synergy between active sites and plasmonic nanostructures in photocatalysis is discussed in detail after briefly introducing the material synthesis and characterization methods. Active sites can promote the coupling of solar energy harvested by plasmonic metal to catalytic reactions in the form of local electromagnetic fields, hot carriers, and photothermal heating. Moreover, efficient energy coupling potentially regulates the reaction pathway by facilitating the excited state formation of reactants, changing the status of active sites, and creating additional active sites using photoexcited plasmonic metals. Afterward, the application of active site-engineered plasmonic nanostructures in emerging photocatalytic reactions is summarized. Finally, a summary and perspective of the existing challenges and future opportunities are presented. This review aims to deliver some insights into plasmonic photocatalysis from the perspective of active sites, expediting the discovery of high-performance plasmonic photocatalysts.

Improved H2S sensitivity of nanosized BaSnO3 obtained by hydrogen peroxide assisted sol-gel processing

Barium stannate is a mixed-metal oxide with a perovskite structure and unique electric, catalytic, and sensing properties. Surface chemistry determines gas sensing behavior, which depends on materials synthesis and processing methods. A novel technique was invented for obtaining BaSnO3 nanoparticles using a hydrogen peroxide assisted sol-gel process. However, to date, the sensing behavior of such prepared barium stannate nanoparticles has not been investigated. In this work, we obtained pure and La-modified BaSnO3 by the hydrogen peroxide-assisted sol-gel method and comparatively studied the composition, microstructure, and gas sensing behavior using as a reference barium stannate prepared by a conventional hydrothermal route. The increased sensitivity and selectivity to H2S were observed for the sol-gel obtained BaSnO3, and the sensing behavior was improved at temperatures higher than 150 °C by La(5%)-modified of barium stannate. The sensing mechanism was revealed by in situ infrared and Raman spectroscopy. The superior sensitivity and selectivity of the sol-gel obtained materials were attributed to lower surface contamination by adsorbed carbonate groups compared to hydrothermally obtained BaSnO3. The surface modification by La3+ species further reduced the carbonate impurity and enhanced the adsorption and oxidation of H2S gas at the BaSnO3 surface.

Porous polycarbazole materials prepared by ionothermal synthesis method for carbon dioxide adsorption and electrochemical capacitors

AbstractThe scopes of synthesis methods of porous polycarbazole materials are still under continuous developments because the polycarbazole materials with high stability and excellent porosity are suitable for various advanced applications. Here, ionothermal synthesis method for preparing porous polycarbazole materials is reported for the first time, by which a series of polycarbazole materials with good porosity and high yield are synthesized. Thereinto, the ferric chloride plays the roles of catalyst and molten solvent for preparing porous polycarbazole materials. The transformation of the pore structure due to slight carbonization during the process of ionothermal synthesis shows profound impacts on application performances. As intercomparison among these polymers, some porous polycarbazole materials with the predominant micropores possess a good performance of carbon dioxide uptake, others with micro‐mesopore structures show a high capacity of electrochemical energy storage. This simple and practicable method provides a pathway for synthesizing novel porous polycarbazole materials and similar porous organic polymers.

Research progress of synthesis of high-performance perovskites and its derivatives based on polyhedral distortion

Corner-shared coordination polyhedral crystals (CSCPCs) represented by perovskites have unique and various properties in optics, electrics, and magnetism, leading to their broad applications such as in serving as ferroelectric material, fast ionic conductors, and electro/photo-catalysts. However, the excellent properties are owned only by a very small fraction of CSCPS phases. How to obtain such phases through structural operation has always been a research hotspot and a bottleneck in related fields. Herein, we review the recent research progress of the synthesis of high-performance CSCPC materials from the perspective of phase structure, in order to clarify the intrinsic rules of phase evolution and reveal the mechanism behind the phase manipulation. We first systematically summarize the types of polyhedra and crystal frameworks in CSCPCs and classify the polyhedral distortions as three main types, i.e. cation displacements, polyhedral rotations, and deformations. Based on that, we further analyze and conclude different material synthesis methods. We find that most traditional synthesis methods rely on the phase transitions induced by the change of external physical conditions at a macroscopic level, such as composition, temperature, and pressure. Recently, there was an emerging synthesis method focusing on the microscopic manipulation of polyhedral geometry and topology, such as phase constructions according to tolerance-factor and substrate-proximity effects. The macroscopic synthesis methods and the microscopic synthesis methods share the same phase manipulation mechanism: making crystals transit into the structure-specified phases by inducing polyhedral distortions. The only difference is that the latter is more target-oriented, but its applications are currently limited to octahedral coordination tilt/rotation systems. Expanding its application scope is still a challenge. In addition, we propose two aspects that may be useful in optimizing the synthesis method: one is to clarify the origin of induced distortions and the interaction between different distortions, and the other is to customize the guidelines based on computer science. We hope that the research progress reviewed in this article can provide some valuable references and inspirations for designing and synthesizing the high-performance CSCPC materials.

Growth of two-dimensional single crystal materials controlled by atomic steps

Since the successful mechanical exfoliation of graphene in 2004, two-dimensional materials have aroused extensive research and fast developed in various fields such as electronics, optoelectronics and energy, owing to their unique structural and physicochemical properties. In terms of synthesis methods, researchers have made further advancements in the atomic step method, building upon traditional techniques such as mechanical exfoliation, liquid-phase exfoliation, vapor-phase deposition, wet chemical synthesis, and nanomaterial self-assembly. These efforts aim to achieve high-quality large-scale two-dimensional single crystal materials. In this article, the representative research on the growth of two-dimensional single crystal materials controlled by atomic steps in recent years is reviewed in detail. To begin with, the research background is briefly introduced, then the main synthesis methods of two-dimensional single crystal materials are discussed and the challenges and reasons for the difficulty in epitaxially preparing non-centrosymmetric materials are analyzed. Subsequently, the growth mechanisms and recent advances in the preparation of two-dimensional single crystal materials assisted by atomic steps are presented. The theoretical basis and universality of atomic step-controlled nucleation in two-dimensional single crystal material are analyzed. Furthermore, the challenges and future directions for achieving large-scale, directionally controllable two-dimensional single crystal materials are predicted. Finally, potential applications of the step method in the future scalable chip device fabrication are systematically discussed.

Formation of intermetallic PdIn nanoparticles: influence of surfactants on nanoparticle atomic structure.

Bimetallic nanoparticles have been extensively studied as electrocatalysts due to their superior catalytic activity and selectivity compared to their monometallic counterparts. The properties of bimetallic materials depend on the ordering of the metals in the structure, and to tailor-make materials for specific applications, it is important to be able to control the atomic structure of the materials during synthesis. Here, we study the formation of bimetallic palladium indium nanoparticles to understand how the synthesis parameters and additives used influence the atomic structure of the obtained product. Specifically, we investigate a colloidal synthesis, where oleylamine was used as the main solvent while the effect of two surfactants, oleic acid (OA) and trioctylphosphine (TOP) was studied. We found that without TOP included in the synthesis, a Pd-rich intermetallic phase with the Pd3In structure initially formed, which transformed into large NPs of the CsCl-structured PdIn phase. When TOP was included, the syntheses yielded both In2O3 and Pd3In. In situ X-ray total scattering with Pair Distribution Function analysis was used to study the formation process of PdIn bimetallic NPs. Our results highlight how seemingly subtle changes to material synthesis methods can have a large influence on the product atomic structure.

Recent Progress of Flexible Photodetectors Based on Low‐Dimensional II–VI Semiconductors and Their Application in Wearable Electronics

AbstractFlexible photodetectors exhibit many advantages such as a good bendability, foldability, and even stretchability as well as weight light, which have triggered a widely concerned in wearable electronics including wearable monitoring, wearable image sensing, self‐powered integrated electronics, etc. Recently, various II–VI semiconductor nanostructures have become promising candidates in flexible photodetectors due to their unique characteristics, such as direct bandgap semiconductors, excellent optical and electric properties, high quantum efficiency, and inherent mechanical flexibility. Herein, the most recent progress on low‐dimensional (0D, 1D, 2D, and related heterostructures) II–VI semiconductors based flexible photodetectors and their application in wearable electronic is reviewed. First, a brief introduction of the main sensing mechanisms and key figures of merits for photodetectors is presented. Then, the recent progresses on flexible photodetectors are provided, in which the functional materials synthesis methods are also discussed. More importantly, the applications of the flexible photodetectors are summarized, including wearable monitoring sensors, image sensors, and self‐powered integrated wearable electronics. Finally, the challenges and the future research direction of the flexible photodetectors are discussed, meanwhile the outlook for the development of flexible photodetectors in the future integration of wearable electronic is also provided.

Aesthetic Dimension of Sacred Monody in Cultural and Educational Environment in Ukraine in 17th Century

The purpose of the article. The paper is devoted to the influence of the Greek-Byzantine spiritual heritage on the Ukrainian cultural and educational environment. The methodology of the study uses the historical-chronological method to reproduce the sequence of development of the sacred monody in European culture, primarily in Ukraine. The method of analysis and comparison has been used to identify common and distinctive international features of the development of sacred monody. The method of material synthesis helped summarise all the important conditions for the development of Ukrainian monophonic singing. The scientific novelty of the work is that it consistently examines the influence Byzantine monody on Ukrainian liturgical practice. The study is based on the practice of colophonic style of the Byzantine sacred monody. Conclusions. The aesthetic canons of the Greek-Byzantine spiritual culture were fully adapted with the Christian rite and reflected in the sacred monody. In the future, this determined the implementation of important church and educational reforms in the 16th century and the development of all layers of Ukrainian culture. At the same time, educational centres were developed, and printing houses at brotherly schools provided schoolchildren with the necessary textbooks. And what is important, all children without exception already at the initial stage of education got to know and studied the first notated collections of sacred monody, spreading the ancient traditions of singing in all social strata of society.
 Key words: aesthetics, sacred monody, neumes, five-line notation, medieval singing, colophonic style, irmologion, church music education.

In2O3 sensing electrode prepared by salt melt method for impedancemetric-type NH3 sensor

Salt melt synthesis is a kind of inorganic material synthesis method developed in modern times, which has certain potential advantages and development prospects. The sensing electrode (SE) material In2O3 was synthesized by the salt melt method. The composition and morphology of the synthesized products under different conditions were studied in detail by combining XRD, SEM and TEM characterization. The results show that the salt melt method can facilely synthesize high-purity In2O3 powder at a lower temperature, and its morphology changes regularly with the change of reaction conditions. The effects of synthesis times and temperatures on the gas-sensing performance of In2O3 were discussed. The sensor based on In2O3 (380 °C − 30 min)-SE exhibited superior gas-sensing performance in the range of NH3 concentration of 50–500 ppm. The NH3 response characteristics exhibited little effect at different relative humidity (RH) and oxygen partial pressure conditions. In addition, the sensor exhibited good repeatability and selectivity.

Progress of Single-Crystal Nickel-Cobalt-Manganese Cathode Research

The booming electric vehicle industry continues to place higher requirements on power batteries related to economic-cost, power density and safety. The positive electrode materials play an important role in the energy storage performance of the battery. The nickel-rich NCM (LiNixCoyMnzO2 with x + y + z = 1) materials have received increasing attention due to their high energy density, which can satisfy the demand of commercial-grade power batteries. Prominently, single-crystal nickel-rich electrodes with s unique micron-scale single-crystal structure possess excellent electrochemical and mechanical performance, even when tested at high rates, high cut-off voltages and high temperatures. In this review, we outline in brief the characteristics, problems faced and countermeasures of nickel-rich NCM materials. Then the distinguishing features and main synthesis methods of single-crystal nickel-rich NCM materials are summarized. Some existing issues and modification methods are also discussed in detail, especially the optimization strategies under harsh conditions. Finally, an outlook on the future development of single-crystal nickel-rich materials is provided. This work is expected to provide some reference for research on single-crystal nickel-rich ternary materials with high energy density, high safety levels, long-life, and their contribution to sustainable development.

Carbon Dioxide Capture in Metal-Organic Frameworks

Excessive carbon dioxide emissions have caused several environmental problems. This has an unpromising impact on the Earth's ecosystem. Metal-organic frameworks (MOFs) attracted more and more attention because of their extraordinary specific surface area, adjustable framework and excellent stability in the effective capture and conversion of carbon dioxide. This article introduced the main synthesis methods of MOF materials, including ionothermal synthesis, mechanochemical synthesis, sonochemical synthesis and ultrasound synthesis method. Each synthesis method of MOFs has its advantages such as shorter reaction times or faster screening rates, which contribute to the development of the synthesis of MOFs. The key evaluation metrics for carbon dioxide capture using MOFs including adsorption isotherm, adsorption ability, enthalpy and high selectivity also were discussed, which have a direct impact on the capture of carbon dioxide. Additionally, the main carbon capture by MOFs in power plants, such as post-combustion capture, capture before combustion and oxy-fuel combustion were also highlighted.

Enhanced optoelectrical performance of ultraviolet detectors based on self-assembled porous zinc oxide nanostructures

A templated self-assembly technique was utilized in the present study to grow porous zinc oxide nanostructures. The nanostructures were formed by the electrochemical deposition of ZnO through the interstitial spaces between polymer microsphere templates. After the deposition, polymer microspheres were removed by dissolving in chloroform solvent, leaving porous ZnO nanostructures. This technique is benefited from facile controllability of the pore morphology and size by varying the diameter of microspheres. X-ray diffraction analysis showed a dominant peak corresponding to the hexagonal ZnO structure. Moreover, no significant structural strain was observed after the removal of spheres unlike the other synthesis methods of porous materials. The improved photoluminescence (PL) properties revealed an enhancement in the light capturing capability of the systems due to the multiple scattering of light in the pore walls. The porous sample showed a PL blue-shift compared to the flat one, indicating a reduction in crystallite size of ZnO nanostructures. To assess the photonic applications of synthesized porous ZnO substrates, a metal-semiconductor-metal photodetector was developed via the metallization of ZnO nanostructures, and their optoelectrical properties were tested under UV radiation. The results showed an improvement in photosensitivity and quantum efficiency of devices based on porous ZnO substrates which can be assigned to the larger exposed area and elevated rates of electron-hole generation in this sample.

A novel high entropy perovskite fluoride anode with 3D cubic framework for advanced lithium-ion battery

High-entropy materials are recently attracted significant attention due to their variability of composition and entropy stabilizing phase structure. However, the current mainstream synthesis methods of high-entropy materials require high-energy ball milling and calcination, which limits their further generalization. In this work, a new class of high-entropy perovskite fluorides (HEPFs) as an anode material using for LIBs is reported. In particular, a high-entropy fluoride of KMgMnFeCoNiF3 (TM5) and a series of medium-entropy fluorides (TM4) including KMnFeCoNiF3 (TM4-Mg), KMgFeCoNiF3 (TM4-Mn), KMgMnCoNiF3 (TM4-Fe), KMgMnFeNiF3 (TM4-Co), and KMgMnFeCoF3 (TM4-Ni) are prepared by a facile ball milling with hydrothermal method. Interestingly, the TM5 electrode shows better cycling performance (120 mAh g−1 at 2 A g−1 over 1000 cycles with ∼99% coulombic efficiency) and rate performance (472–57 mAh g−1 at 0.1–3.2 A g−1 current densities) than TM4. The key to such improvement depends on the high-entropy effect together with the synergistic effects of multiple electroactive redox centers. It is believed that this work can provide a new idea for the design and synthesis of high-entropy perovskite materials in the future.

Facile fabrication of novel high-performance electromagnetic interference shielding nickel foam

Porous structure design is critical and challenging in the fabrication of high-performance electromagnetic interference (EMI) shielding materials. Herein, the porous Ni skeleton is prepared by solution combustion method and cured through polydimethylsiloxane (PDMS), forming a Ni foam by the stacking of porous Ni. The properties of PDMS and porous Ni endow Ni foam with stable structure, excellent electrical conductivity, magnetic properties and porous internal structure, which make electromagnetic waves not only experience conductive loss and magnetic loss, but also reflect and scatter several times in the porous interface during propagation inside the foam, further improving the shielding efficiency (SE) of Ni foam. Compared with the as-prepared foam mixed with graphene (rGO) and polyaniline (Pani) powder, the Ni foam shows the best structural strength, lowest resistivity (1.32 Ω/cm) and highest SE (56 dB). Moreover, the rough surface and PDMS modification enable Ni foam to obtain self-cleaning and anti-fouling properties, expanding its application range. This study opens an innovative, simple and efficient synthesis method for porous shielding materials which extends the application prospects of porous materials in the field of EMI shielding.

Graphene/Quantum Dot Heterostructure Photodetectors: From Material to Performance

AbstractOwing to its high carrier mobility, electrical conductivity, and thermal/chemical stability, graphene is an ideal candidate material for photodetection. However, the weak light absorption of graphene significantly limits its practical applications in photodetectors. Quantum dots, with strong light‐absorption capacity and well‐adjustable band gap, are widely hybridized with graphene to realize wide‐range and intense light absorption for effective photodetection. A detailed literature review on graphene/quantum dot heterostructure photodetectors is in urgent need to clearly point out the fundamentals, material synthesis methods, and performance engineering strategies. Here, first, the significance of graphene/quantum dot heterostructure photodetectors, from the mechanism to performance indicators, is systematically discussed. Second, different synthesis methodologies for the graphene/quantum dot heterostructure are overviewed. Additionally, the engineering strategies, including surface treatment, chemical doping, and size modification, to tune the photoelectric performance are critically commented. Finally, challenges and outlook for the development of graphene/quantum dot heterostructure photodetectors are pointed out.

Docking studies and thiourea-mediated reduced graphene oxide nanosheets' larvicidal efficacy against Culexquinquefasciatus

The larvicidalproperty of graphene oxide (GO) and thiourea-reduced graphene oxide (T-rGO)was assessed against Culexquinquefasciatuslarvae. A simple water-soluble material synthesis method was used. The transformation of graphene into graphene oxide was accomplished in a single step. Under mild conditions, grapheneoxidewasdissolved in water to form a solution. Structure, optical, and microstructural features of the synthesized samples wereevaluatedusing a variety of analytical tools to compare the samples. Both GO and RGO, as well as GO, showed strong larvicidal potential when used against the third instar larvae of the Culexquinquefasciatus mosquito, with LC50and LC90values of 1.71 and 5.17 ppm and 1.89 and 5.00 ppm, respectively.As a result, our study showed that all of the GO and T-rGO under investigation create larvicidal compounds that could be employed to support efforts to control mosquito populations. It also offers an alternative method for producing GO and rGO on a big scale, which may be used in the future for a variety of biomedical applications.The binding efficacy of the active compounds against AChE1 was studied using Auto dock and the results were observed to be highly promising.