Self-sacrificing Template Method Research Articles

Zn-doped hollow cubic MnO2 as a high-performance cathode material for Zn ion batteries.

Manganese-based compounds have the characteristics of high theoretical capacity, low cost and stable performance, thus become a research hotspot for cathode materials of zinc-ion batteries (ZIBs). However, in the process of charging and discharging, it is accompanied by problems such as structural collapse and low conductivity, which resulted in severe capacity degration during cycles. In this paper, a kind of Zn2+ doped MnO2 hollow cube cathode material (Zn-MnO2) was prepared by self-sacrificing template method. The Zn2+ doped in MnO2 crystals can induce oxygen vacancies in the structure, thereby improving the structural stability ion diffusion coefficient and electrical conductivity of the material. After 100 cycles at 0.3 A g-1, the high specific capacity of 281.2 mA h g-1 is still maintained. Through ex-situ XPS and ex-situ XRD tests, the mechanism of charge-discharge process was discussed. The results show that the storage mechanism of Zn-MnO2 is H+ and Zn2+ insertion/removal and Mn3+/Mn2+ two-electron reaction pathway. The total state density (TDOS) and partial state density (PDOS) of Zn-MnO2 and MnO2 further demonstrated that the doping of Zn2+ enhanced the electron conductivity and is beneficial to the electron transfer during the electrochemical reaction.

N-doped carbon-coated CoSe2/ZnIn2S4 Z-scheme heterojunction for enhanced visible-light photocatalytic performances

N-doped carbon (NC)/CoSe2/ZnIn2S4 Z-scheme heterojunction was constructed by growing ZnIn2S4 on N-doped carbon-coated CoSe2 derived from the metal-organic framework (ZIF-67) via the self-sacrificing template method and hydrothermal method. X-ray photoelectron spectroscopy, electron paramagnetic resonance, and density-functional theory (DFT) calculations demonstrate that NC/CoSe2/ZnIn2S4 (NSZ) Z-scheme heterojunction was constructed with CoSe2 as an electron mediator. The optimal 5NSZ composite achieved 97.3% in photocatalytic degradation efficiency of tetracycline hydrochloride (TCH) within 30 min, and H2O2 production of 645.3 μM under visible light for 60 min. Moreover, the top-flight photocatalytic hydrogen evolution (PHE) rate of 6772.9 μmol g−1 h−1 is 19.1 folds and 2.2 folds higher than pure ZnIn2S4 and Pt–ZnIn2S4, respectively. The photoreduction CO2 gas produces rates of CO (53.7 μmol g−1 h−1), C2H4 (7.0 μmol g−1 h−1), and C2H6 (6.4 μmol g−1 h−1) products were obtained within 10 h under visible light. This work provides an effective strategy for designing unique noble-metal-free Z-scheme heterojunction photocatalysts to purify the environment and produce clean energy.

Controllable synthesis of 3D PdCu/Ti3C2Tx hierarchical nanostructures for chemiresistive room temperature H2 sensors

To enhance the detection performance of hydrogen (H2), we employed a self-sacrificing template method to prepare a three-dimensional (3D) PdCu-modified Ti3C2Tx nanocomposite, denoted as PdCu/Ti3C2Tx. Within 3D PdCu/Ti3C2Tx nanocomposite, PdCu as the active center component, was evenly distributed on Ti3C2Tx nanosheets. The unique architecture increased the exposure of active center sites, while the Ti3C2Tx nanosheets provided additional gas diffusion channels, thereby contributing to improved gas sensing performance. Comparing to PdCu nanoparticles, PdCu/Ti3C2Tx exhibited an enhancing response and a fast response time of 4 s to 0.5 % H2. PdCu/Ti3C2Tx also showed an ultra-low detection limit of 0.1 % H2 and excellent repeatability, selectivity and long-term stability. The outstanding gas sensing performance could be attributed to the 3D structure and the heterostructure between PdCu and Ti3C2Tx. The insights gained from this study provide novel perspectives for designing and synthesizing high-performance gas-sensitive materials.

Electron transfer in MOF-derived cobalt-magnesium oxide–carbon microsphere composite catalytic ozonation of thiamphenicol

Cobalt-magnesium oxide–carbon microsphere composite (Co-MgO-CMS), Cobalt-carbon nanosheet composite (Co-CNS), and magnesium oxide–carbon nanorod composite (MgO-CNR) were synthesized by the MOFs self-sacrificing template method. And they were used as the catalysts for catalytic ozonation of thiamphenicol (20 mg/L) in water at an initial pH of 7.0. The phase of Co-MgO-CMS is mainly composed of metallic cobalt, magnesium oxide and carbon according to X-ray diffraction and transmission electron microscopy analyses. Thiamphenicol removal efficiency is enhanced through Co-MgO-CMS catalytic ozonation (75.4 %, in 6 min), compared with those in ozonation alone (39.8 %), Co-CNS catalytic ozonation (43.2 %), MgO-CNR catalytic ozonation (65.1 %) and Mg-Co binary oxide (Mg2CoOy) catalytic ozonation (69.0 %). Self-increasing of solution pH, protonated hydroxyl groups and electron transfer on metallic Co and lattice Co2+ are advantageous for the ozone decomposition into reactive oxygen species in Co-MgO-CMS catalytic ozonation. Owing to the metallic Co in Co-MgO-CMS, the electron transfer ability of Co-MgO-CMS is better than that of Mg2CoOy according to the in situ electrochemical test. Moreover, electron transfers directly from metallic Co to ozone. While protonated hydroxyl groups are the key for electron transfer on lattice Co2+. A possible degradation pathway for thiamphenicol in Co-MgO-CMS catalytic ozonation is proposed according to the detected intermediates. This work provides insight into improvement on electron transfer ability of concerted acid-base catalyst in heterogeneous catalytic ozonation.

Bimetallic alloy nanoparticles embedded in N-doped carbon-based as an anode for potassium-ion storage material

Metal-organic frameworks (MOFs) have great potential as anode materials for potassium-ion batteries (PIBs) due to their hierarchical porous structures, large number of reaction sites, and adjustable chemistry. However, the larger size of potassium ions adversely impacts the electrochemical performance and specific capacity. Therefore, it is imperative to develop novel electrode materials featuring distinctive structures for PIBs. This study achieved bimetal introduction by adding Ammonium ferric citrate during ZIF-67 growth. The resulting metal–organic skeleton of the bimetallic alloy nanoparticle (FeCo@PAZ-C) exhibits a core–shell structure and adorned with numerous microspheres on its surface, thereby offering an abundance of active sites for K+ storage. This architecture effectively reduces the diffusion path length for potassium ions and enhances electron transport pathways, ultimately contributing to improved performance. At 100 mA g−1 and after 500 cycles, the FeCo@PAZ-C electrode material demonstrated a stable specific capacity of 328 mAh/g with 95 % capacity retention. This self-sacrificing template method for MOFs offers a new approach to developing high-capacity and cycling-stable potassium-ion battery materials, broadening their potential applications.

Highly Thermally Conductive Polydimethylsiloxane Composites with Controllable 3D GO@f-CNTs Networks via Self-sacrificing Template Method

Highly Thermally Conductive Polydimethylsiloxane Composites with Controllable 3D GO@f-CNTs Networks via Self-sacrificing Template Method

Forming SnS@C/MoS2 nanotubes with high specific surface area via self-sacrificing template method as superior performance anode for lithium-ion batteries

1) The coated carbon from Sn-MOF carbonization with the nanosheet architecture improves the specific surface area; 2) the heterojunction between SnS and MoS2 provides active sites; 3) the surface carbon provides a large number of active sites.

Facile Synthesis of N-Doped Metal-Free Catalysts for Oxygen Reduction Reaction via a Self-Sacrificed Template Method Using Zinc Amino-Acid Complex

Facile Synthesis of N-Doped Metal-Free Catalysts for Oxygen Reduction Reaction via a Self-Sacrificed Template Method Using Zinc Amino-Acid Complex

Nitrogen/phosphorus co-doped carbon decorated with metallic zinc for high-performance potassium-ion batteries

Carbonaceous anodes of potassium-ion batteries (PIBs) hold sluggish adsorption and diffusion kinetics due to the large radius of K+, leading to poor cyclic stability and low specific capacity. Herein, an amorphous carbon material composed of N/P-doped active sites and trace amount of metallic zinc (Zn-NPC) is prepared through a facile self-sacrificing template method. Both experimental data and theoretical calculations indicate the co-doping of metallic zinc, and N/P atoms contribute to the low charge transfer impedance, high electronic conductivity, significant adsorption behavior, and remarkable diffusion kinetics of K+ ions. As a result, Zn-NPC anode delivers high capacity of 300.1 mA h g−1 at 50 mA g−1, and superior cycle performance with a reversible capacity of 196.1 mA h g−1 after 1400 cycles at 200 mA g−1. This work will open window for the doping strategy of carbon material and facilitate the practical application of PIBs in the energy storage field.

Interface-induced electron transfer in sandwich-like hierarchical hollow CoP@NC hybrid for boosted hydrogen evolution reaction in alkaline electrolyte

It is necessary to develop an effective non-noble metal electrocatalyst to promote the slow kinetics of alkaline electrolytes. Here, a self-sacrificing template method is developed to construct sandwich-like layered hollow structures CoP@NC (H-CoP@NC) for promoting hydrogen evolution kinetics. The hierarchical hollow nanostructures give greater contact area between catalyst and electrolyte, shorten ion/electron transport distances, and expose more active sites. More importantly, the introduction of nitrogen-doped carbon (NC) can effectively prevent the aggregation of CoP and improve the electron transfer rate during phosphorylation. The overpotential of the catalyst H-CoP@NC is only 173 mV at a current density of 10 mA/cm2. The excellent catalytic activity can be attributed to the unique structure and the doping of heteroatom. This work provides a new method for designing hollow nanomaterials.

Hierarchical porous carbon synthesis by carbonized polymer dots-based sacrificial template for high-performance supercapacitors

The performance of carbon-based supercapacitors is primarily determined by their porous carbons with customizable structures. Targeted regulation of the porous' size and amount is a crucial but challenging research topic to pursue higher power density and energy density. Additional loading of carbonized polymer dots (CPDs) on existing materials to optimize pore structures and modify pseudocapacitive groups is a feasible alternative. CPDs are treated as the desirable hard template, due to their high stability and controlled small-size to tailor reasonable pore distribution. Here, the hierarchical porous carbon was fabricated by activating the composite of CPDs and hyper-crosslinking polymer (HCP), which originated from the Friedel-Crafts reaction of small molecules. After the CPDs self-sacrificing template method based on the “excavation” of CPDs with small size (＜10 nm) by KOH, the optimal material owned abundant small mesopores (2 ∼ 10 nm) and large specific surface area (4241 m2·g−1). Thanks to the excellent structures, the optimized product yielded ultrahigh energy density at high power density (35.8 Wh·kg−1at 37497 W·kg−1) in 1 M TEATFB/PC. Thus, the CPDs-based pore-formation and regulation strategy is a potentially helpful alternative for fabricating high performance carbon-based supercapacitors.

In-situ construction of nano-sized Ni-NiO-MoO2 heterostructures on holey reduced graphene oxide nanosheets as high-capacity lithium-ion battery anodes

Transition metal oxide anodes for lithium-ion batteries (LIBs) have evoked widespread concern by reason of their high theoretical capacity, abundance, and diversity. Nevertheless, they suffer from severe volume expansion/contraction and slow reaction kinetics during cycling, resulting in poor electrochemical lithium storage performance. Herein, we ingeniously design a unique multi-component composite with Ni-NiO-MoO2 heterostructure nanoparticles in-situ dispersed on holey reduced graphene oxide (rGO) nanosheets using a facile self-sacrificed MOFs template method. The integration of Ni-NiO-MoO2 heterostructure nanoparticles and well-conductive rGO nanosheets with unique nanoholes can collaborate the inherent properties of each component to improve the reaction kinetics and synergistically enhance the lithium storage property. Thereby, the Ni-NiO-MoO2/rGO composite as a LIB anode exhibits outstanding cycling performance with a high reversible capacity (910 mAh g−1 after 220 cycles at 500 mA g−1) as well as excellent rate capability maintaining the great capacity retention of 534 mAh g−1 at 3000 mA g−1. This research offers a vital inspiration for designing and fabricating multi-component metal oxide-based composite anode materials for high-performance LIBs.

Evolution of Highly Biocompatible and Thermally Stable YVO4:Er3+/Yb3+ Upconversion Mesoporous Hollow Nanospheriods as Drug Carriers for Therapeutic Applications.

In recent times, upconversion nanomaterials with mesoporous hollow structures have gained significant interest as a prospective nano-platform for cancer imaging and therapeutic applications. In this study, we report a highly biocompatible YVO4:1Er3+/10Yb3+ upconversion mesoporous hollow nanospheriods (YVO4:Er3+/Yb3+ UC-MHNSPs) by a facile and rapid self-sacrificing template method. The Rietveld analysis confirmed their pure phase of tetragonal zircon structure. Nitrogen adsorption–desorption isotherms revealed the mesoporous nature of these UC-MHNSPs and the surface area is found to be ~87.46 m2/g. Under near-infrared excitation (980 nm), YVO4:Er3+/Yb3+ UC-MHNSPs showed interesting color tunability from red to green emission. Initially (at 0.4 W), energy back transfer from Er3+ to Yb3+ ions leads to the strong red emission. Whereas at high pump powers (1 W), a fine green emission is observed due to the dominant three-photon excitation process and traditional energy transfer route from Er3+ to Yb3+ ions. The bright red light from the membrane of HeLa cells confirmed the effective cellular uptake of YVO4:Er3+/Yb3+ UC-MHNSPs. The resonant decrease in cell viability on increasing the concentration of curcumin conjugated YVO4:Er3+/Yb3+ UC-MHNSPs established their excellent antitumor activity. Therefore, the acquired results indicate that these YVO4:Er3+/Yb3+ UC-MHNSPs are promising drug carriers for bioimaging and various therapeutic applications.

Self-supported PdNi dendrite on Ni foam for improving monohydric alcohol and polyhydric alcohols electrooxidation

Despite considerable efforts to study direct alcohol fuel cells (DAFCs), the development of efficient bifunctional catalysts for monohydric alcohol and polyhydric alcohols remains a great challenge. This work reports the preparation of self-supported PdNi dendrites on Ni foam (self-supported PdNi DNTs/NF) with a large specific surface area by a simple self-sacrificing template and hydrothermal method. The presence of NF with enrichment of nucleation sites is crucial for the generation of self-supported PdNi DNTs. The as-obtained self-supported PdNi DNTs/NF exhibits an excellent property for ethanol and glycerol electrooxidation with the mass activity of 2375.7 mA mgcat−1 and 2451.6 mA mgcat−1, the specific activity of 10.07 mA cm−2 and 10.84 mA cm−2, respectively, in alkaline media, which should attribute to abundant high-index facets and low-coordinated atoms on the edge of branches. Furthermore, the PdNi DNTs/NF exhibits outstanding long-term durability in the current–time test for 7200 s with superior anti-CO poisoning performance, possessing a potential application in DAFCs.

Hollow Capsule NiCo2 NS Prepared by Self-Sacrificing Template Method for High-Efficiency Bifunctional Catalyst and Its Application in Zn-Air Battery.

Exploring the application of high-efficiency bifunctional oxygen catalysts to rechargeable zinc-air batteries has been a research hotspot in recent years. We succeeded in obtaining NiCo2 NS with a hollow capsule structure through the self-sacrificing template method, which has a larger specific surface area and can provide more active sites for electrocatalysis relative to his solid. The introduction of S can change the valence distribution of N and the electronic structure of the M-N bond, so that NiCo2 NS exhibits excellent performance in the overpotential and stability of the oxygen reduction and oxygen evolution reactions. It shows an overpotential of 154 mV at 10 mA cm-2 and a half-wave potential of 0.76 V. When used as a bi-functional catalyst in zinc-air batteries, it exhibits good stability within 400 h. The flexible battery assembled by NiCo2 NS also shows excellent performance, and can be cycled stably for 20 h. The current maintains good stability when it is bent at different angles during the cycle.

The Composite-Template Method to Construct Hierarchical Carbon Nanocages for Supercapacitors with Ultrahigh Energy and Power Densities.

3D hierarchical carbon nanocages (hCNC) are becoming new platforms for advanced energy storage and conversion due to their unique structural characteristics, especially the combination of multiscale pore structure with high conductivity of sp2 carbon frameworks, which can promote the mass/charge synergetic transfer in various electrochemical processes. Herein, the MgO@ZnO composite-template method is developed to construct hCNC and nitrogen-doped hCNC (hNCNC), which integrates the advantages of the in situ MgO template method and ZnO self-sacrificing template method. The hierarchical MgO template provides the scaffold for depositing carbon nanocages, while the self-sacrificing ZnO template helps create abundant micropores while promoting the graphitization degree, so that the microstructures of the products are effectively regulated. The optimized hCNC and hNCNC have an increased specific surface area and conductivity, which can further boost the mass/charge synergetic transfer. As the electrode materials of supercapacitors, the optimal hCNC(hNCNC) exhibits a high specific capacitance of 281(348)Fg-1 in KOH and 276(297)Fg-1 in EMIMBF4 electrolytes at 1Ag-1 . The ultrahigh energy and power densities are realized, accompanied by a high-rate capability and long cycling stability. The record-high energy densities of 141.8-71.4Whkg-1 are achieved in EMIMBF4 at power densities of 10.0-250.4kWkg-1 .

Enhanced thermal performance of phase change materials supported by hierarchical porous carbon modified with polydopamine/nano-Ag for thermal energy storage

In order to solve the problem of low thermal conductivity of hierarchical porous carbon-based (HPC) composite phase change materials, a new method was proposed in this paper, in which HPC was modified with polydopamine (PDA) and silver nanoparticles successively, and then incorporated with polyethylene glycol (PEG) to form shape-stabilized phase change composite material (SSPCM). The HPC was prepared by self-sacrificing template method using sucrose and sodium bicarbonate as starting materials. The micro structure, thermal conductivity, thermal stability, chemical compatibility and Photo-thermal conversion capability of the SSPCM were analyzed. The results showed that the SSPCM prepared from the support material modified by PDA and silver nanoparticles still had good chemical compatibility. Besides, the thermal conductivity of SSPCM was significantly improved by 58% compared to the original material, showing superior thermal properties. It was worth noting that the photo-thermal conversion capability of the SSPCM was significantly higher than that of the original material. The SSPCM synthesized on the basis of functionalized hierarchical porous carbon had promising applications in photo-thermal conversion and thermal energy storage and transformation.

Ternary photocatalysts based on MOF-derived TiO2 co-decorated with ZnIn2S4 nanosheets and CdS nanoparticles for effective visible light degradation of organic pollutants

A high-efficiency visible-light-responsive CdS/ZnIn2S4/TiO2 photocatalyst was prepared for the first time by the self-sacrificing template method followed by a two-step chemical bath process.

CoNx/g-C3N4 Nanomaterials Preparation by MOFs Self-sacrificing Template Method for Efficient Photocatalytic Reduction of U(VI)

CoN<i>_x</i>/g-C₃N₄ Nanomaterials Preparation by MOFs Self-sacrificing Template Method for Efficient Photocatalytic Reduction of U(VI)

Self-sacrificing template method to controllable synthesize hollow SnO2@C nanoboxes for lithium-ion battery anode

A self-sacrificing template method is a common and straightforward way to synthesize hollow nanomaterials. In this study, a self-sacrificing template method was used for the facile preparation of well-defined hollow SnO2@C nanoboxes. CaSn(OH)6 nanocubes, as sacrificial templates, reacted with glucose under hydrothermal conditions to synthesize hollow SnO2 nanoboxes. The surface of the hollow SnO2 nanoboxes via the carbonization of polydopamine, resulting in hollow SnO2@C nanoboxes. The electrochemical performance test confirmed the excellent rate performance (806.5, 785.0, 718.8, 612.4, and 297.8 mA h g−1 at 0.1, 0.2, 0.5 1.0, and 2.0 A g−1, respectively) and outstanding reversible capacity (786.9 mAh g−1 after 100 cycles) of the hollow SnO2@C nanoboxes. The carbon-coated hollow structured SnO2 nanoboxes provide buffer space for volume expansion, high electrolyte contact area, and short ion transfer path, resulting in improved cycling stability and rate performance.