Category Archives: ChemNanoMat

Gold Microstructures by Thermolysis of Gold(III) Di‐isopropyldithiocarbamate Complexes

Posted on 12 March 2024 by

The reaction between gold(III) chloride and sodium di-isopropyldithiocarbamate produces two compounds. Sub-micron sized gold microcrystals are produced when the complexes are thermally decomposed in the solid-state. The morphology of the resultant gold microcrystals is determined by the choice of complex.

Abstract

Elemental gold was formed by thermolysis of gold(III) dithiocarbamate single-source precursors, which exist as two complexes. The complexes were readily synthesised from the reaction between chloroauric acid and sodium di-isopropyldithiocarbamate and could be isolated from each other. The thermal decomposition processes were evaluated using thermogravimetry and electrical resistance measurements. The structure and purity of the resultant gold was examined using scanning electron microscopy. The resultant gold materials were drastically different and dependent on the thermolysed complex.

Design and Preparation of a Bifunctional Nanobiohybrid Catalyst by Combining Palladium and α‐Amylase Enzyme: Application in One‐pot Chemoenzymatic Catalysis

Posted on 12 March 2024 by nParmjeet Kaur, nVikas Tyagin

A heterogeneous recyclable nanobiohybrid catalyst was developed by combining palladium nanoparticles and α-amylase enzyme. Further, the developed catalyst was employed to catalyze the one-pot chemoenzymatic synthesis of functionalized biphenyls and bis(indolyl)methanes.

Abstract

A chemoenzymatic approach that combines chemical and bio-catalyst has proven very useful in synthetic chemistry, however, mutual deactivation of chemical and bio-catalyst when employed in the same pot is still a challenge. In this context, the development of nanobiohybrid catalysts has played an important role and overcoming the issue of mutual deactivation between catalysts to a certain extent. Herein, we design and synthesize a novel heterogeneous recyclable nanobiohybrid catalyst comprising palladium nanoparticles and α-amylase from Aspergillus oryzae immobilized onto halloysite nanotubes as a solid heterogeneous support. Further, the wider applicability of the developed nanobiohybrid catalyst is revealed in the one-pot chemoenzymatic synthesis of functionalized biphenyls and bis(indolyl)methanes which consists of Pd-catalyzed Suzuki-Miyaura coupling and α-amylase mediated aza-Michael addition or electrophilic substitution reactions respectively. Further, the robustness and generality of the developed one-pot chemoenzymatic synthesis are demonstrated by incorporating different substitutions at the starting materials and obtaining the corresponding products in moderate to good yields.

In‐Situ Colloidal Synthetic Route to Monodispersed NiCo2S4 Nanoparticles over Nickel Foam for High‐Performance Supercapacitive Charge Storage

Posted on 12 March 2024 by nYe Wang, nJunling Yu, nFengyi Yang, nQing Yangn

Monodispersed NiCo₂S₄ nanoparticles are grown in-situ on nickel foam by a one-step colloidal synthetic route, and they deliver a high specific capacitance of 1790.8 F/g at 1 A/g via a three-electrode system and also maintain outstanding energy-storage capacity, high energy density and stability in a two-electrode cell. This study provides a feasible way to design and fabricate electrodes effectively.

Abstract

One-step colloidal synthetic route was adopted to in-situ grow monodispersed NiCo₂S₄ nanoparticles (NPs) on nickel foam (NF) from metallic salts with benzyl disulfide in the media of oleylamine and octadecene. Owing to the favorable dispersion and considerable redox activity of NiCo₂S₄ along with tight and binder-free connection with NF, the obtained battery-type supercapacitor delivered a specific capacitance of 1790.8 F g⁻¹ at 1 A g⁻¹ via a three-electrode system. Simultaneously, it just degraded 40 % at 20 A g⁻¹ and maintained 86.8 % of initial specific capacitance (C₀) after 2000 cyclic trials at 10 A g⁻¹. When the NiCo₂S₄ NPs were assembled with active carbon (AC) forming an asymmetric capacitor device of NiCo₂S₄ NPs//AC, it delivered an energy density (E) of 48.7 W h kg⁻¹ at a power density (P) of 161.1 W kg⁻¹, and kept 21.9 W h kg⁻¹ at a high P of 8.05 kW kg⁻¹. Meanwhile, the capacitor manifested preeminent cycling life (C=94.5 % C₀ after 5000 cyclic trials) at 5 A g⁻¹. The in-situ grown NiCo₂S₄ NPs on NF without any binder exhibited high performance in energy storage, providing a feasible way to improve the electrochemical performance of the electrode materials.

Directional Growth of Bi2WO6 with Highly Exposed Facets on 2D‐Co3O4 for different Properties under two Light Sources

Posted on 12 March 2024 by

We synthesized a novel p-n heterojunction with rose-like morphology self-assembled from 2D-Co₃O₄ and Bi₂WO₆ nanosheets with highly exposed {010} facets, named Bi₂WO₆/Co₃O₄ composite. It was considered that the composite served as a traditional heterojunction under ultraviolet light, while it played a role as a Z-scheme photocatalyst under visible light, respectively.

Abstract

A composite of two or more materials usually results in enhanced specific properties. In this paper, a kind of composite material composed of Bi₂WO₆ with highly exposed {010} facets and 2D-Co₃O₄ was prepared by a one-pot reaction and then applied to decontaminate hydrocortisone in wastewater. The Bi₂WO₆/Co₃O₄ composite possessed a rose-like surface microtopography self-assembled from Bi₂WO₆ and Co₃O₄ nanosheets. The micro-interface analysis showed that {110} facets of Co₃O₄ and {010} facets of Bi₂WO₆ were glued in situ and formed heterojunction. Additionally, the removal ability of hydrocortisone through Bi₂WO₆/Co₃O₄ varied under different light sources, which was 85.0 % under ultraviolet light and 97.3 % under visible light within 60 min. It was considered that Bi₂WO₆/Co₃O₄ was similar to a traditional heterojunction and the major reactive species was H₂O₂ under ultraviolet light, while it played a role as a Z-scheme photocatalyst and the major reactive species was ⋅OH under visible light. Finally, product analysis of hydrocortisone demonstrated that the dexter chain broke whatever under ultraviolet or visible light, but the breakage of parent nucleus appeared only under visible light. This research revealed the enhanced catalytic properties of p-n heterojunction catalysts and indicated the specifically exposed facets are promising for organic contaminants in water.

Tunable Polymer Micelles as Template Directing Growth of MOFs Crystals in Surfactant‐Free Emulsion to Fabricate Chitosan‐Based Copolymer/ZIF‐8 Nanostructure

Posted on 12 March 2024 by nXiaozhu Zhao, nZongxin Li, nFengchuan Guo, nNaipu He, nWen Li, nXuerui Zhaon

The morphology of micelles in surfactant-free emulsion was regulated by adjusting the oil-water ratio and concentration of amphiphilic copolymer. Subsequently, polymer micelles served as templates to direct the assembly of ZIF-8 crystals in the surfactant-free emulsion to fabricate polymer/ZIF-8 composite materials (ZIF-8@CSP) with various structures.

Abstract

An amphiphilic chitosan-g-poly N-(3-dimethylaminopropyl) methacrylamide (CS-g-PDMAPMA, CSP) was proposed and synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT), and further employed as emulsifier to construct a surfactant-free emulsion. The morphology of micelles in surfactant-free emulsion was regulated by adjusting the oil-water ratio and concentration of amphiphilic copolymer. Subsequently, polymer micelles served as templates to direct the assembly of ZIF-8 crystals in the surfactant-free emulsion to fabricate polymer/ZIF-8 composite materials (ZIF-8@CSP) with various structures. Specifically, ZIF-8@CSP with various architectures such as spheres, rods, cubes, leaf-shaped flakes, cross-flowers and wrinkled cubes were obtained by varying the concentration of CSP, the addition sequence of ZIF-8 precursors and the ratio of oil-water.

Designing and Screening of Moisture‐Swing Porous Adsorbents for Rapid CO2 Capture from Air

Posted on 12 March 2024 by nJun Liu, nZhen Zhang, nChenyang Liang, nWeishu Wang, nTao Wangn

A promising adsorbent of Quaternary amine based materials is synthesized for CO₂ air capture, and the effect of humidity, temperature and micropore on CO₂ adsorption kinetics is analyzed. The adsorbents with microporous structure showed much higher adsorption kinetics than that with macroporous structure, and the highest kinetics performance of CO₂ adsorption ever reported is obtained.

Abstract

Quaternary amine(QA)-functionalized adsorbents using moisture swing method are demonstrated to have vast application prospect in capturing CO₂ from the ambient air. However, the poor kinetic performance and limited sorbents remain a great challenge. In this work, the porous resins were screened and membrane with controllable porous structure was designed for CO₂ air capture, and the effects of the varieties of QA-based resins and external environmental conditions (humidity and temperature) on CO₂ adsorption performance were quantitatively investigated. The results show that the kinetic performance of porous resins are far superior to the existing QA-based direct air capture(DAC) materials, and the half-time of D290 type membrane is only 102 s, much less than that of gelatinous resin, which is about 2400 s. The effect of microporous structure on CO₂ adsorption rate increases with the increase of humidity, while only slightly effect was found on macroporous adsorbents. The research results can provide basic data for the application of CO₂ capture in different occasions.

Preparation of SnO2@graphite Anode based on the Oriented Deposition Methodology with Superior Electrode Behavior for Li Ion Battery

Posted on 12 March 2024 by

SnO₂@graphite composite derived from the oriented deposition methodology is employed as the anode material for LIBs. The SnO₂@graphite electrode exhibits satisfactory electrode behavior with respect to capacity, rate capability and durability. Besides, the SnO₂@graphite/LiFePO₄ full cell exhibits higher energy and power densities over that of graphite/LiFePO₄ full cell.

Abstract

SnO₂-based anode materials are deemed to be one of the most prospective anode materials for Li ion batteries (LIBs) with higher theoretical capacity as compared to conventional graphite. However, the weak electrical conduction and large volume expansion limit its application in eVeryday life. Here, a simple and low-cost oriented deposition methodology is developed to prepare SnO₂@graphite composite, which is obtained based on the redox reaction mechanism between SnSO₄ and graphite. SnO₂ nanoparticles are uniformly anchored on the carbon layer of graphite. The close anchoring of SnO₂ in graphite effectively inhibits the volume expansion of SnO₂ during lithiation/delithiation processes, and good combination state between them guarantees the excellent electrical conductivity of the composite. As anode for LIBs, SnO₂@graphite electrode delivers superior reversible capacity and provides an improved rate capability compared to graphite electrode. Benefiting from the tight combination of SnO₂ and graphite, the Li ion diffusion coefficient of SnO₂@graphite electrode is almost twice that of graphite electrode. Pairing with LiFePO₄ cathode, the SnO₂@graphite/LiFePO₄ full cell exhibits higher energy/power densities by comparison with graphite/LiFePO₄. Besides, this advanced SnO₂@graphite composite material with superior anode behavior can be mass produced by the reported methodology.

An Overview on Lead Halide Perovskite based Composites and Heterostructures: Synthesis and Applications

Posted on 12 March 2024 by nFency Sunny, nSubila Kurukkal Balakrishnan, nNandakumar Kalarikkaln

Lead halide perovskites find numerous applications owing to the photophysical properties but faces glaring stability issues. Heterostructures and composites based on lead halide perovskites leads to improved and stable applications. This review explores the synthesis methods followed to produce these hybrid materials focusing on the improvements required in fundamental studies and their applications.

Abstract

Lead Halide Perovskites (LHPs) have garnered great attention in recent times due to their astonishing properties that range from direct tunable bandgaps, strong light absorption, defect resistance and the easily accessible synthesis of high-quality crystals and films. These materials find application in multitudinous fields including photovoltaics, optoelectronics, lasers, catalysis and in the emerging field of spintronics. Though they show exceptional optoelectronic properties with enhanced applications, the instability of LHPs act as a main downside when it comes to real world applications. Integrating complementary materials to LHPs that form composites with better stability along with improved performance have started to gain traction. These composites and heterostructures incorporating functional materials with LHPs have made the utilization of perovskites in everyday life more feasible. The existing synthetic strategies for heterostructure and composites heavily draw from the techniques used for halide perovskite synthesis. These methods often under-utilize the potential of exploring the synergy of materials interaction. This review explores the synthesis methods followed to produce these hybrid materials focusing on the improvements required in terms of fundamental studies and their applications.

Dispersed Nickel Phosphide Cocatalyst on Nb2O5 Ultrathin Nanosheets to Boost Photocatalytic CO2 Reduction

Posted on 12 March 2024 by nZijian Wang, nMengdie Li, nMingjiao Xiao, nYanze Wei, nRanbo Yu, nZumin Wangn

Tiny NiP nanoparticles dispersed was used as an inexpensive, stable, and active cocatalysts on ultrathin Nb₂O₅ nanosheets to replace the noble metal Pt. Owing to the extended light harvesting, enhanced carrier separation, and improved surface reaction, the NiP/Nb₂O₅ exhibits even higher activity and selectivity towards CO₂ photocatalytic reduction. And the roles and function mechanisms of the cocatalyst were studied.

Abstract

Photocatalytic CO₂ reduction holds great promise to solve energy shortage and global warming. Nb₂O₅ has demonstrated superiority in CO₂ activation and selectivity regulation, but suffers from poor light absorption ability and fast carrier recombination. To tackle these problems, we designed and synthesized ultrathin Nb₂O₅ nanosheets which were decorated with tiny NiP nanoparticles as cocatalyst. In this way, light absorption range broadened, carrier migration distance reduced, charge transfer resistance decreased, and surface reaction kinetics promoted. Consequently, the as-prepared NiP/Nb₂O₅ showed notably enhanced activity (148.7 μmol ⋅ g⁻¹) and selectivity (82.1 %) towards CO, as well as remarkable stability. This work paves the way for cheap and earth abundant alternatives as cocatalysts and deepens the understanding of their functions in CO₂ photoreduction.

A Facile Synthetic Approach for TiO2@NiO Core‐shell Nanoparticles using TiO2@Ni(OH)2 Precursors and their Photocatalytic Application

Posted on 12 March 2024 by nPankaj Rana, nPethaiyan Jeevanandamn

TiO₂@NiO core-shell nanoparticles, synthesized using TiO₂@Ni(OH)₂ as precursors, show better photocatalytic activity compared to pure TiO₂ and NiO nanoparticles.

Abstract

The current study presents a simple and an efficient chemical method for the synthesis of TiO₂@NiO core-shell nanoparticles (CSNPs) as photocatalyst for effective degradation of rhodamine B (RhB) in an aqueous solution upon sunlight irradiation. First, TiO₂ spheres were synthesized using a wet chemical method. Then, TiO₂@Ni(OH)₂ precursors were prepared via homogeneous precipitation and TiO₂@NiO core-shell nanoparticles were obtained on calcination of the precursors. The synthesized precursors and the TiO₂@NiO CSNPs were analyzed using XRD, FT-IR, FESEM and DRS. XRD data shows the presence of both TiO₂ and NiO phases in the TiO₂@NiO samples. FE-SEM and TEM analyses confirm coating of NiO NPs on TiO₂ spheres with varying shell thickness (40 nm to 170 nm). Optical studies reveal that TiO₂@NiO CSNPs possess band gap of about 3.7 eV. Photoluminescence (PL) results show lower recombination rate of e⁻ and h⁺ pairs in the TiO₂@NiO CSNPs. XPS studies confirm the presence of different elements in the TiO₂@NiO CSNPs. Magnetic investigations reveal ferromagnetic behavior of the core-shell NPs at 5 K. The TiO₂@NiO CSNPs were explored as photocatalyst for the degradation of rhodamine B in water under natural sunlight. The TiO₂@NiO CSNPs exhibit better photocatalytic activity compared to TiO₂ and NiO nanoparticles.