Template Precursor Research Articles

Structural Aspects of Materials in Optimization of Fuel Cell Electrodes.

Today's energy problems, caused by the irrational consumption of fossil fuels and, as a result, terrible environmental consequences, require the global population to quickly introduce clean energy sources. Electrochemical power sources, which include the fuel cell, provide the technological basis for electrical energy production. While proton exchange membrane fuel cells (PEMFC) rely on platinum based catalysts, obtaining stable and earth abundant catalytic materials for the oxygen reduction reaction (ORR) is an important step towards large scale integration. Our work focusses on FeNC noble-metal free catalysts in PEMFC conditions. The reaction conditions are much more complex in comparison to half cells, as transport processes and e.g. carbon oxidation affect the performance data. Thus, it turns out to be extremely difficult to determine the most important factors affecting the catalytic activity and stability of the material and to optimize the structure of the membrane-electrode assembly as several factors are overlaying each other: For example, the pyrolysis temperature affects the surface area, degree of graphitization and iron-related composition as well as extent of surface functional groups [1]. The metal loading, pyrolysis temperature and a use of possible precursor templates effects the structure, surface area as well as ORR activity and selectivity of catalysts [2], [3].In our recent work, it was shown that in contrast to the electrochemical characteristics observed in rotating disc electrode (RDE) measurements, the best performing catalyst was prepared at the highest investigated temperature for both FC activity and stability [1]. In contrast, the dwell time had only a limited impact at low pyrolysis temperature, whereas a variation from 30 min to 90 min gave significant destruction of molecular FeNx moieties for the high temperature pyrolysis. [1]To gain further insights on the effect of preparation parameters on FC performance and in specific stability, we coupled a quadrupole mas-spectrometer to the cathode exhaust to follow possible release of CO2 depending on the applied conditions. The data are interpreted together with the structural characterization of the materials. We will discuss how the dwell time and pyrolysis temperature effected on morphology changes of the catalyst and to what extent this impacts the FC activity and short-term stability.AcknowledgementsA.O. would like to thank you the TU Darmstadt for the Future talent scholarship, UIK gratefully acknowledges financial support by the BMBF young research group StRedO (03XP0092), and we thank Y. Ostroverkh, and Z. L. Müller, for the consultation and assistance with the fuel cell setup.[1] J. Scharf, M. Kübler, V. Gridin, W.D.Z. Wallace, L. Ni, S.D. Paul, U.I. Kramm, Relation between half-cell and fuel cell activity and stability of FeNC catalysts for the oxygen reduction reaction, (2022) SusMat, accepted (doi: 10.1002/sus2.84).[2] P.Theis, W.D. Z. Wallace, L. Ni, M. Kübler, A. Schlander, R. W. Stark, N. Weidler, M, Gallei, U. I. Kramm. Systematic study of precursor effects on structure and oxygen reaction activity of FeNC catalysts, (2021) Philos. Trans. Royal Soc. A PHILOS T R SOC A, (doi: 10.6084/m9.figshare.c.5506708).[3] P. Boldrin, D. Malko, A. Mehmood, U. I. Kramm, S. Wagner, S. Paul, N. Weidler, A. Kucernak. Deactivation, reactivation and super-activation of Fe-N/C oxygen reduction electrocatalysts: Gas sorption, physical and electrochemical investigation using NO and O2., (2021) Appl. Catal. B, Vol. 292, 120169, (doi: 10.1016/j.apcatb.2021.120169).

Metal–Organic Framework‐Derived Ultrafine ZnO/Co3ZnC Particles Embedded in N‐Doped Carbon Concave‐Dodecahedron Towards Enhanced Lithium Storage

AbstractTransition metal oxides (TMOs) are potential anode materials for lithium‐ion batteries (LIBs) owing to their superior theoretical capacities, environmental benignity and abundant supply. However, because of the intrinsically poor conductivity, inevitable volume variation, inferior capacity and cyclic stability, the progress of TMOs in practical application is seriously hindered. In this study, a new N‐doped carbon concave‐dodecahedron has been successfully manufactured through a facile method utilizing bimetallic zeolitic imidazolate framework (ZnCo‐ZIF) as both precursor and sacrificial template, in which ultrafine ZnO/Co3ZnC nanoparticles uniformly distributed on the surface can provide additional active sites to effectively accelerate the diffusion of lithium ions. As a result, the as‐prepared ZnO/Co3ZnC/C (ZCC) anode exhibits outstanding mechanical tolerance during lithiation process. Attributed to the superior structure and compositional optimization, the ZCC anode achieves remarkable electrochemical performance with considerable high‐rate capacity (424 mAh g−1 at 2.0 A g−1) and ultralong cyclability (942 mAh g−1 at 0.2 A g−1 after 300 cycles).

MOF-Derived Co3O4 Nanoparticles Catalyzing Hydrothermal Deoxygenation of Fatty Acids for Alkane Production

Designing economical and nonprecious catalysts with a catalytic performance as good as that of noble metals is of great importance in future renewable bioenergy production. In this study, the metal–organic framework (MOF) was applied as a precursor template to synthesize Co3O4 nanoparticles with a carbon matrix shell (denoted as M-Co3O4). To select the synthesized optimal catalyst, stearic acid was chosen as the model reactant. The effects of catalyst dosage, methanol dosage, water dosage, temperature, and reaction time on catalytic efficiency were examined. Under the designed condition, M-Co3O4 exhibited high catalytic performance and the catalyst showed higher conversion of stearic acid (98.7%) and selectivity toward C8–C18 alkanes (92.2%) in comparison with Pt/C (95.8% conversion and 93.2% selectivity toward C8–C18). Furthermore, a series of characterization techniques such as scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption isotherms (Brunauer–Emmett–Teller (BET) method), and thermogravimetric analysis (TGA) was applied to investigate the physicochemical properties of the catalysts. Finally, we proposed that decarbonization (deCO) could be the presumably mechanistic pathway for the production of C8–C18 alkanes from the decomposition of stearic acid.

Coordination compound-derived Fe4N/Fe3N/Fe/CNT for efficient electrocatalytic oxygen evolution: a facile one-step synthesis in the absence of extra nitrogen source

By annealing an Fe(III)–coordination compound (Fe–CC), [FeCl3(Hbta)2] (Hbta = benzotriazole) in the presence of a carbon nanotube precursor (PCNT) template, an Fe4N/Fe3N/Fe/CNT heterostructure was successfully synthesized without an extra nitrogen source. The decomposition of the Hbta in Fe–CC under high-temperature annealing can produce carbon sheets and reduced graphene oxide (rGO), and the presence of CNTs can alleviate the stacking of the in situ-generated carbon materials. Meanwhile, iron nitride nanoparticles (NPs) can be anchored on the carbon sheets, and the anchoring effect efficiently prevents the agglomeration of NPs and increases the amount of active catalytic sites for the oxygen evolution reaction (OER). Fe4N/Fe3N/Fe/CNT shows an excellent OER activity with a Tafel slope of 63 mV dec−1 as well as overpotentials of 121 (η 10) and 275 mV (η 100) at 10 and 100 mA cm−2, respectively — far exceeding commercial RuO2 and other catalysts. Density functional theory calculations show that the excellent OER performance of Fe4N/Fe3N/Fe/CNT is associated with the Fe4N/Fe3N heterojunction, which can improve the electron conductivity and boost the electron transfer from N to Fe. The Fe4N/Fe3N/Fe/CNT catalyst exhibits long-term OER activity during 100 h of electrolysis at 20 mA cm−2. This is related to the dual coatings of the in situ-generated thin carbon shell and few-layered rGO on the surface of the iron nitride NPs, which can protect the fast leaching of iron nitride during the OER process. Furthermore, the effects of the annealing temperature, the PCNT template and the heating rate on the calcined products were investigated.

Iron and nitrogen anchored hierarchical hollow porous carbon microtubes for an electrocatalytic oxygen evolution reaction

The development of active nonprecious-metal and heteroatom-doped materials is critical for the oxygen evolution reaction (OER). Herein, asphaltene-derived carbon-coated Fe- and N-doped hierarchical hollow porous carbon microtubes were prepared through feasible freeze-drying and carbonization/activation strategies. Cotton with a fibrous morphology acted as a soft template and carbon precursor, while asphaltene with easy graphitization properties was utilized to stabilize the structure of microtubes and accelerate the charge conductivity. Meanwhile, Fe- and N-doping changed the electronic structure of carbon and increased the number of active sites. In particular, the optimum sample displayed excellent OER activity with a lower overpotential of 261.4 mV at 10 mA/cm2 and Tafel slope of 94.60 mV/dec under alkaline conditions. Moreover, the catalyst demonstrated excellent long-term durability with a 10% attenuation rate after continuous operation for 50 h by the chronoamperometry method at a constant potential of 1.5 V. This work provides a strategy for the effective resource utilization of biomass and asphaltene to prepare highly efficient OER electrocatalysts.

Electrochemical Dopamine Detection using a Fe/Fe3O4@C Composite derived from a Metal‐Organic Framework

AbstractIn this paper, a novel composite of Fe/Fe3O4@C is synthesized by taking a Fe‐metal‐organic framework (Fe‐MOF) as precursor template. Different treating temperature (450, 550, 650 and 750 °C) were carried out to investigate the composite of calcined products. The Fe/Fe3O4@C‐650 modified glassy carbon electrode (Fe/Fe3O4@C‐650GCE) shows good electrocatalytic activity towards dopamine (DA) oxidation. Three electrochemical measuring methods of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and amperometry i‐t are adopted to investigate the sensing behaviors of Fe/Fe3O4@C‐650/GCE. The results show that: the sensors based on CV and DPV technology exhibit excellent advantages in the aspect of sensitivity and linear range thanthose of the sensor based on amperometry i‐t technology. Meanwhile, the sensor based on CV method shows good selectivity for dopamine, and can resist the influence of various sugars, uric acid, ascorbic acid, as well as Na+ and K+. The sensor also shows good stability and repeatability in the sensing process. In addition, the Fe/Fe3O4@C‐650/GCE could be successfully applied in the DA detection in the human serum.

Hierarchically Porous MOFs Synthesized by Soft-Template Strategies.

The past few decades have been witnessing the rapid research boom of metal-organic frameworks (MOFs), which are assembled from metal nodes and multitopic organic linkers. In virtue of their modular assembly mode, they can be tailored according to desired functions to satisfy numerous potential applications. However, most initially reported MOFs were restricted to the microporous regime, limiting their practical applications with bulk molecules involved. Therefore, the research attention was immediately directed toward enlarging the intrinsic pore size of frameworks by extending the secondary building units or organic ligands. Unfortunately, the synthesis of more extended ligands is frequently tedious, and the most resultant MOFs are not sufficiently stable, restricting their popularization. The soft-template strategy is recognized as a promising avenue to produce hierarchically porous MOFs (HPMOFs), although early attempts generally failed due to the incompatibility between the surfactant self-assembly and guided crystallization process of MOF precursors in the organic phase. Therefore, developing a rational soft-template strategy to achieve the precise control of morphology and porosity of HPMOFs is of great significance.In this Account, we present our recent progress on the development and applications of HPMOFs prepared by soft-template strategies. We highlight the key issues upon using the soft-template strategy to synthesize HPMOFs. To enhance the interaction between the template and MOF precursor, a long-chain monocarboxylic acid strategy is introduced to synthesize HPMOFs with irregular mesopores in the organic phase. Then, to improve the order of mesopores, an aqueous-phase synthesis method using amphoteric surfactants as templates is developed to prepare ordered HPMOFs. To further enlarge the pore size and make the synthesis conditions of MOFs compatible with the self-assembly of surfactants, a salting-in species-induced self-assembly strategy is proposed and coupled with the structure-directing properties of copolymer templates to synthesize a series of HPMOFs with large mesopores and even macropores. This salting-in ion-mediated self-assembly (SIMS) strategy paves the way to modify the pore size, pore structure, morphology, and chemical composition of HPMOFs. The separated but intimately interconnected hierarchical pores in the resultant HPMOFs can not only realize rapid mass transport but also isolate different-size guest molecules so that they are competent for a broad range of applications including protein digestion, cascade catalysis, enzyme-assisted substrate sensing, and DNA cleavage. Finally, the limitations, challenges, and future developments of this rapidly evolving field are described. This Account with a highlight to the soft-template strategies not only provides interesting insights to understand the assembly process between templates and MOFs but also inspires an optimization of the properties of HPMOFs from diverse aspects for desired applications.

Exploring the Effect of Glycerol and Hydrochloric Acid on Mesoporous Silica Synthesis: Application in Insulin Loading.

Mesoporous silica (MPS), a carrier for active pharmaceutical ingredients, has a wide range of particle and pore morphology. A thorough understanding of ingredients used in MPS synthesis is an important prerequisite for optimizing its physicochemical characteristics. The present study aimed to evaluate the effect of glycerol and hydrochloric acid on the characteristics of synthesized MPS. Ordered MPS materials were synthesized using the pluronic P123 template and tetraethyl orthosilicate (TEOS) precursor. A three-level factorial design was employed to study the interaction between glycerol and hydrochloric acid. The optimized MPS particles were reasonably uniform in shape (short and rod-shaped) and < 1 μm in size with a smooth surface morphology. The nitrogen adsorption–desorption analysis revealed that the uniform cylindrical pores of the prepared MPS had a diameter > 5 nm and a total surface area > 500 m2/g. With increasing acid and glycerol concentrations, the particle size of MPS decreased. However, while the glycerol increased the heterogeneity of the synthesized particles, the acid decreased it. The developed MPS was successfully loaded with a biological drug (insulin) with a 21.94% encapsulation efficiency. The MPS prepared in this study exhibits potential applications as a drug delivery carrier for drugs with a large molecular weight.

Autonomous Chemistry Enabling Environment-Adaptive Electrochemical Energy Storage Devices

Autonomous Chemistry Enabling Environment-Adaptive Electrochemical Energy Storage Devices

Mechanisms for self-templating design of micro/nanostructures toward efficient energy storage.

The ever-growing demand in modern power systems calls for the innovation in electrochemical energy storage devices so as to achieve both supercapacitor-like high power density and battery-like high energy density. Rational design of the micro/nanostructures of energy storage materials offers a pathway to finely tailor their electrochemical properties thereby enabling significant improvements in device performances and enormous strategies have been developed for synthesizing hierarchically structured active materials. Among all strategies, the direct conversion of precursor templates into target micro/nanostructures through physical and/or chemical processes is facile, controllable, and scalable. Yet the mechanistic understanding of the self-templating method is lacking and the synthetic versatility for constructing complex architectures is inadequately demonstrated. This review starts with the introduction of five main self-templating synthetic mechanisms and the corresponding constructed hierarchical micro/nanostructures. Subsequently, the structural merits provided by the well-defined architectures for energy storage are elaborately discussed. At last, a summary of current challenges and future development of the self-templating method for synthesizing high-performance electrode materials is also presented.

ORAOV 1 Detection Made with Metal Organic Frameworks Based on Ti3C2Tx MXene.

In this work, a two-dimensional (2D) MOF sheet with electrochemiluminescence (ECL) activity is prepared with Ti3C2Tx MXene as the metal precursor and the meso-tetra(4-carboxyl-phenyl) porphyrin (H2TCPP) as the organic ligand. The atomically thin 2D Ti3C2Tx MXene is utilized as the metal precursor and soft template to produce the MOF with a 2D nanosheet morphology (Ti3C2Tx-PMOF). Ti3C2Tx MXene is a kind of strong electron acceptor, which can deprotonate H2TCPP due to the high electronegativity and low work function of its terminal atoms. The deprotonated H2TCPP continues to bind with Ti atoms to form the 2D MOF sheet. The ECL activity is inherited from H2TCPP and stabilized by introducing Ag NPs. Then, we construct an ECL biosensor based on the Ag NPs/Ti3C2Tx-PMOF to detect the oral cancer overexpressed 1 (ORAOV 1). A bipedal three-dimensional DNA walker strategy is adopted to further improve the biosensor sensitivity. As expected, the biosensor exhibits sterling sensitivity and selectivity. The ECL biosensor responds linearly to ORAOV 1 concentrations in the range of 10 fM-1 nM, and the detection limit is as low as 3.3 fM (S/N = 3). It means that Ag NPs/Ti3C2Tx-PMOF is a potential material to design and construct the high-performance ECL biosensors.

Facile and green synthesis cobalt embedded in N-doped porous carbon under zeo-waste conditions as an efficient oxygen evolution reduction catalyst

A facile and green method is developed to synthesize cobalt species embedded in a nitrogen-doped carbon matrix (P–Co@NCs). The materials are synthesized using hard template precursors via single-step in-situ thermal treatment under free solvent conditions. The optimal P–Co@NC composite prepared through rational synthesis and synergic composition shows an efficient electrocatalytic performance for oxygen evolution reduction (OER). The P–Co@NC exhibits the OER overpotential of 350 mv at 10 mA cm −2 and low Tafel 73 mv·dec −1 in 0.1 M KOH electrolyte. The advantage of catalyst is the dispersion of Co species, which are in close interaction with nitrogen-doped carbon matrix. The Co-Nx plays a dominating role among Co species in P–Co@NC and is well protected by the nitrogen-doped carbon matrix layer. That resulted in efficient electron transport on CNTs (high conductivity) that improves the OER performance of P–Co@NC compared to the reference catalysts (IrO 2 and B–Co@NC). The P–Co@NC also showed excellent cycling performance from long-term chronoamperometry testing. Interestingly, the P–Co@NC catalyst could be synthesized straightforward via a short solvent-free single-step process that introduced it as a green and environmental friendly method, which can be potential to develop catalyst based on metal embedded N-doped carbon. • The single-step, rapid and effective “green” route of the IST method to synthesize cobalt species embedded in nitrogen-doped carbon (P–Co@NC). • The advantages of economic practicability, minimization of synthesis period, energy consumption without any waste formation could outweigh the catalyst for OER performance. • The advantage of Co dispersion and close interaction with nitrogen-doped carbon matrix showed efficient catalytic performance. • The efficient electron transport on CNTs (high conductivity) improved the OER performance of P–Co@NC over the reference catalysts (IrO 2 and B–Co@NC).

Selective hydrogenation of glucose to sorbitol with tannic acid-based porous carbon sphere supported Ni–Ru bimetallic catalysts

Ni–Ru bimetallic porous carbon sphere (Ni–Ru@PCS) catalysts were synthesized via formaldehyde-assisted, metal-coordinated crosslinking sol–gel chemistry, in which biomass-derived tannic acid and F127 surfactant were used as carbon precursor and soft template, respectively, and Ni2+ and Ru3+ were used as cross-linkers. In the developed method, Ni–Ru particles became uniformly dispersed in the carbon skeleton due to strong coordination bonds between metal ions (Ni2+ and Ru3+) and tannic acid molecules and bimetal interactions. The as-synthesized Ni–Ru10:1@PCS catalyst with a loading Ni:Ru mole ratio of 10:1 was applied for the selective hydrogenation of glucose to sorbitol, and provided 99% glucose conversion with a sorbitol selectivity of 100% at 140 °C in 150 min reaction time and exhibited good stability and recyclability in which sorbitol yield remained at 98% after 4 cycles with little or no metal agglomeration. The catalyst was applied to glucose solutions as high as 20 wt% with 97% sorbitol yields being obtained at 140 °C in 20 h. The developed bimetallic porous carbon sphere catalysts take advantage of sustainably-derived materials in their structure and are applicable to related biomass conversion reactions.

(Fe, Ni)S2@MoS2/NiS2 hollow heterostructure nanocubes for high-performance alkaline water electrolysis

Hollow hybrid heterostructures are regarded to be promising materials as bifunctional electrocatalysts for highly efficient water electrolysis due to their intriguing morphological features and remarkable electrochemical properties. Herein, with FeNi-PBA as both a precursor and morphological template, we demonstrate the rational construct of cost-effective (Fe,Ni)S2@MoS2/NiS2 hollow hybrid heterostructures as bifunctional electrocatalysts for alkaline overall water splitting. Microstructural analysis shows that the hybrid is a kind of hierarchical heterostructure composed of MoS2/NiS2 nanosheets/nanoparticles in situ grown on hollow (Fe,Ni)S2 nanocubes with abundant heterointerfaces, which effectively maximizes the electrochemical active sites to the accessible electrolyte ions, leading to the promoted charge transfer. As expected, the hybrid shows remarkable alkaline electrocatalytic performance, such as hydrogen evolution overpotential of 176 mV and oxygen evolution overpotential of 342 mV at 50 mA cm−2, as well a cell voltage of 1.65 V at 20 mA cm−2. Moreover, the stability and durability are greatly enhanced under harsh electrochemical conditions. This study opens a new venue for developing earth-abundant bifunctional electrocatalysts with hollow hybrid heterostructures for alkaline water electrolysis in the future.

Fabrication of MOF derivatives composite membrane via in-situ sulfurization for dye/salt separation

In this study, metal-organic framework (MOF) layer on the surface of tubular ceramic substrate was prepared as the precursor template to construct ZIF-67-derived CoS x composite membrane through in-situ sulfurization strategy. During the sulfurization process, ZIF-67 as a template was reacted with sulfur ions to form CoS x . Due to the structure change of the ZIF-67 crystal, the aperture of the CoS x was enlarged with the thickness of the separation layer decreased. Moreover, the reorganization of the separation layer caused by the in-situ sulfurization eliminated the non-selective defects. Therefore, a CoS x composite membrane can be obtained with high separation performance and good stability for dye/salt separation. The effects of sulfurization and operation conditions on membrane performance were studied. The CoS x composite membrane had outstanding permeance (751.6 LMH/MPa) and excellent rejection (>99.5%) for dye molecules, while the rejection for salt was below 18.7%. The separation performance of the CoS x composite membrane can be maintained over 100 h, which exhibited great potential in dye desalination. • A ZIF-67-derived CoS x membrane was constructed by in-situ sulfurization strategy. • The aperture of crystal was enlarged, and grain boundary cracks were eliminated. • The thickness of separation layer was decreased after sulfurization. • The CoS x composite membrane had high dye rejection and low salt rejection. • The permeance of the CoS x membrane was enhanced by 2.8 times.

Silicon micron cages derived from a halloysite nanotube precursor and aluminum sacrificial template in molten AlCl3 as an anode for lithium-ion batteries.

Porous nanostructures have been proposed a promising strategy to improve the electrochemical performance of Si materials as anodes of lithium-ion batteries (LIBs). However, expensive raw materials and the tedious preparation processes hinder their widespread adoption. In this work, silicon micron cages (SMCs) have been synthesized in molten AlCl3 through using spherical aluminum particles as a sacrificial template, and the earth-abundant and low-cost natural halloysite clay as a precursor. The aluminum spheres (1–3 μm) not only act as a sacrificial template but also facilitate the formation of silicon branches, which connect together to form SMCs. As anodes for LIBs, the SMC electrode exhibits a high reversible capacity of 1977.5 mA h g−1 after 50 cycles at a current density of 0.2 A g−1, and 1035.1 mA h g−1 after 300 cycles at a current density of 1.0 A g−1. The improved electrochemical performance of SMCs could be ascribed to the micron cage structure, providing abundant buffering space and mesopores for Si expansion. This promising method is expected to offer a pathway towards the scalable application of Si-based anode materials in the next-generation LIB technology.

Low-temperature synthesis of NaRE(WO4)2 films via anion exchange from layered rare-earth hydroxides (LRHs) films, phase/morphology evolution and photoluminescence

LRH films were prepared via electrodeposition within 10 minutes, and they were used as precursor templates to produce NaRE(WO4)2 films at pH ∼ 10. The obtained NaEu(WO4)2 and NaTb(WO4)2 films exhibit enhanced photoluminescence.

Nanowire-to-Nanoribbon Conversion in Transition-Metal Chalcogenides: Implications for One-Dimensional Electronics and Optoelectronics

The dominant quantum confinement and edge effects in one-dimensional (1D) transition-metal dichalcogenide (TMDC) nanoribbons have given rise to physical properties useful in electronic, optoelectronic, and catalytic applications. Numerous methods of synthesizing TMDC nanoribbons via top-down or bottom-up methods have already been developed. However, controlling the mass growth of these materials remains challenging. We herein describe a predefined growth of zigzag-type TMDC nanoribbons using WTe atomic wires as template precursors. Bundles of WTe wires were annealed in the presence of chalcogen vapors to induce structural transformation into nanoribbons of layered WS2, WSe2, or WTe2. Depending on the stacking arrangement of the WTe wires, vertically or horizontally aligned nanoribbons were generated, forming random or unidirectional networks. The resultant WSe2 nanoribbons showed anisotropic optical responses in Raman and photocurrent measurements, indicating their 1D nature. The present results provide a path for not only the possible structural engineering of TMDC nanoribbons but also their application in sophisticated 1D electronic and optoelectronic devices.

Metal organic framework derived SnS@C composites for efficient sodium storage

Tin monosulfide (SnS) has received extensive attention as a promising anode material toward sodium storage for its high specific capacity. Herein, we reported a simple and facile vulcanization reaction to synthesize SnS particles dispersed into carbonaceous mesoporous frameworks using Sn-based MOFs as the precursor template. The unique structure of SnS@C improves electrical conductivity of SnS and promotes the electrons transfer. The as-prepared SnS@C-500 composite displays superior sodium storage performance, which exhibits a high specific capacity of 510 mAh g−1 over 200 cycles at the current density of 0.5 ​A ​g−1, as well as superior rate capabilities. The current MOF-derived synthesis method offers a simple and effective apporach to synthesis in situ SnS/carbonaceous composites electrode materials.

Waste eliminated by waste under COVID-19 pandemic: Mixed plastic waste derived N,O-rich porous carbon nano-coral reefs for chlorophenol pollutants efficient capture

Both increasing emission of chlorophenol chemicals and plastic waste pollution are severe global environmental challenges, which is worth being explored to respond with a "waste eliminated by waste" coupling treatment strategy. Herein, we propose a one-step recyclable nano-MgO template strategy to prepare in-situ N, O-doped novel porous carbon coral reefs (PCNCR) directly derived from the mixture of real waste PET and melamine formaldehyde resin. The template precursor can be conveniently recycled by facile acetic acid pickling, vacuum evaporation and drying, and the whole preparing process does not involve any toxic solvents, massive consumption of pore-forming agents, or discharge of salty wastewater. The obtained PCNCRs have hierarchical porous structures and abundant N, O-doped species, and the textural parameters can be modulation linearly by varying the mass ratio of magnesium acetate to mixed waste plastics. The optimized PCNCR-1.25 exhibited remarkable adsorption capacity for chlorophenol contaminants (777.5 mg/g for 4-Chloro-3,5-dimethylphenol, PCMX and 538.74 mg/g for 4-Chloro-3-methylphenol, PCMC) in aqueous solution. Adsorption isotherm fitting studies revealed chlorophenol contaminants tended to be rapidly adsorbed on the PCNCR surface in the form of monolayer. And the system reached adsorption equilibrium at about 15 min, which was described by linear driving force model. Reusability test verified that PCNCR-1.25 had excellent adsorption stability for chlorophenol in continuous adsorption-regeneration cycles. DFT calculation illustrated the enhancement of chlorophenol adsorption by heteroatom species, especially nitrogen dopants. This work highlighted a low-cost and sustainable approach to defuse the dual environmental threat of chlorophenol emissions and plastic waste pollution simultaneously.