We present a straightforward one-pot hydrothermal method for the synthesis of zirconia nanodispersions, leading to the formation of stable sols. By simply varying the nature of the stabilizer used, one can obtain a large variety of objects with different sizes, shapes and crystallinities. Our results demonstrate the crucial role played by aliphatic amino acids both during the formation of the objects and after, since their interaction with the surface of the inorganic crystals influences strongly the optical properties and colloidal stability of the latter. Importantly, the versatility of this method allows for the introduction of different dopants, increasing substantially the scope of applications that can be achieved with such nanoscale oxides. The high transparencies and the easy dispersibility of nanoparticles in different liquid matrixes ensure the formation of zirconia-based nanocomposites and ceramics with outstanding optical features for the orthopedic, dental, photonics and chemical sectors. This method can be easily scaled up, being already available for the production of high-quality zirconia nanodispersions at the industrial level.

Metal selenides are essential electrode materials for promising electrochemical energy storage with comparable or improved electrochemical performance than metal oxides. Herein, Se/NiSe2/CoSe2 (S/NS/CS) is fabricated using a solvothermal approach with the assistance of polyethyleneimine, followed by annealing at different temperatures (300, 400, 500, and 600°C) for one hour under an argon atmosphere. After annealing, all electrodes’ physical and electrochemical properties were examined, which determined that the best electrode is NiCo2O4/NiO (NCO/NO) formed at 500°C. Another hydrothermal method uses NCO/NO with SeO2 as a selenium source to prepare S/NS/CS nanocomposite, with a specific surface architecture that enables easy ion movement and strong conductivity, giving it exceptional electrochemical energy storage properties. It exhibited a remarkable capacitance of 468 F g−1 at a current density of 0.5 A g−1. For practical applications, the hybrid S/NS/CS//AC device was designed using S/NS/CS as a positive electrode and commercial activated carbon (AC) as a negative electrode. The asymmetric device demonstrated an excellent capacitance of 142 F g−1 (189 C g−1) and a superb specific energy of 44 Wh kg−1 at a specific power of 840 W kg−1 at a current density of 1 A g−1, providing 80% capacity retention and 100% coulombic efficiency after 5000 cycles.

Copper nanoparticles (Cu2O NPs) supported on graphitic carbon nitride (g-C3N4) have been introduced as an effective heterogenous catalyst for the synthesis of 3-indolmethyl chromones (3a-q) under visible light conditions via the cyclization of o-hydroxyaryl enaminones with 3-indoleacetic acids. The catalyst was thoroughly characterized using various techniques such as FT-IR, PXRD, XPS, FE-SEM, EDX, TEM, and HR-TEM analysis. The optimized reaction conditions enabled the high yield production of a wide range of 3-indolmethyl chromones in a short timespan at room temperature under visible light and method was successfully applied to the gram-scale synthesis. Importantly, the catalyst could be reused for up to five cycles without significant decrease in its activity. This approach aligns with eco-friendly principles, demonstrating favorable green chemistry metrics for compound 3a, including process mass intensity (7.83), environmental impact factor (6.83), atom economy (67.56 %), reaction mass efficiency (60.76 %), chemical yield (92.37 %), mass intensity (1.64), mass productivity (60.97 %), carbon efficiency (69.15 %) and optimum efficiency (89.93 %).

A novel CoNi(CN)₄ nanosheets/CNT interlayer is designed to prevent shuttle effect by adsorption-catalysis process. The iodine species can be adsorbed and catalyzed on the dual-metal centers of the cyanide bridged coordination polymer. The zinc-iodine dual-plating battery with the interlayer shows impressive areal capacity of 3.6 mAh cm⁻² with high cycle stability.

Abstract

Iodine is a promising candidate among the cathode materials in zinc-ion battery. However, iodine cathode suffers from serious shuttle effect by spontaneous generated polyiodide species. In this work, we developed a CoNi(CN)₄/CNT interlayer to prevent shuttle effect by adsorption-catalysis process. The adsorption of the iodine species on CoNi(CN)₄/CNT interlayer is justified by UV-vis spectroscopy and X-ray photoelectron spectroscopy, where the concentration of polyiodides is significantly reduced, and the binding energy of cobalt, nickel, and nitrogen is remarkably reduced by binding with polyiodides. The zinc-iodine dual-plating battery shows significantly higher areal capacity and cycle stability with CoNi(CN)₄/CNT. Moreover, battery with impressive areal capacity of 3.6 mAh cm⁻² and negligible fading over 100 cycles is also achieved, which outperforms state-of the art literatures on zinc-iodine batteries.

The thermal conductivity of micro-sized boron nitride spheres (BNSs), which is challenging to measure directly, was approximated to be that of the BNS pellet in the cross-plane direction, measured by laser flash method. BNSs exhibit a high, isotropic thermal conductivity of 37.2±2.5 W m⁻¹ K⁻¹ and outperform h-BN pellets in heat dissipation for LED lights due to the isotropic structures.

Abstract

Highly integrated and miniaturized electronic devices require advanced thermal management techniques to improve reliability and performance. Thanks to their high thermal conductivity and electrical insulation, boron nitride nanosheets (BNNSs) are commomly used as fillers to construct thermally conductive polymer composites for heat dissipation. However, the BNNS reinforced composites exhibit anisotropic thermal conductivity due to the anisotropic structure of BNNSs. Micro-sized boron nitride spheres (BNSs) with isotropic thermal conductivity are considered one of the best solutions. Nevertheless, precisely measuring the thermal conductivity of BNSs remains a challenge, limiting the understanding of the thermal transport mechanism. Herein, we have successfully estimated the thermal conductivity of BNSs using the laser flash method. Factors influencing BNSs’ thermal conductivity, including precursor, polymer binder and sintering temperature, are also investigated. Under optimized conditions, BNSs exhibit high, isotropic thermal conductivity of 37.2±2.5 W/(m ⋅ K), and the BNS pellet outperforms its h-BN counterpart in heat dissipation for an LED light. This superiority is attributed to outstanding heat transfer performance in the cross-plane direction, in addition to high in-plane thermal conductivity. This study provides a feasible method to estimate the thermal conductivity of spherical materials and highlights promising boron nitride materials with isotropic thermal conductivity for heat dissipation in advanced electronics.

A porous carbon-based monolithic chainmail electrode, namely Co2P@CSA, is fabricated via direct carbonization of Co2+-cross-linked-starch aerogel (Co2+-SA) followed by low-temperature vapor phosphorization. During successive carbonization-phosphorization, the SA framework is formulated into 3D hierarchically porous carbon membrane matrix comprising hollow open carbon microspheres while the cross-linked Co species are converted into uniformly distributed carbon-encapsulated Co2P nanoparticles on carbon microspheres. Thanks to the high porosity, excellent electrolyte wettability, unique chainmail structure, and good mechanical strength, the monolithic Co2P@CSA can be directly used as a binder-free bifunctional electrocatalyst for alkaline water splitting, and it can afford a high current density of 100 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at low overpotentials of 140.0 and 305.5 mV, respectively, with outstanding stability at 50 mA cm-2 for >30 h. More significantly, an alkaline electrolyzer assembled using Co2P@CSA achieves a current density of 100 mA cm-2 for overall water splitting (OWS) at a cell voltage of 1.94 V with unit Faradaic efficiency and provides a high solar-to-hydrogen (STH) conversion efficiency of 13.4 % when driven by a commercial silicon solar cell. This work offers an effective strategy towards cost-effective fabrication of high-performance carbon-based monolithic chainmail electrocatalysts for energy conversion reactions.

This review focuses on cryogels derived from inorganic nanocrystals, prepared using a simple and versatile method of freezing and freeze-drying an aqueous nanoparticle colloid. We explore how factors like freezing temperature and nanoparticle composition can influence the cryogel structure. We discuss the properties and applications, along with the challenges and future directions for this promising material.

Abstract

Cryogels have morphological features that make them interesting for several applications such as catalysis, sensing or tissue engineering. Their interconnected network and open porous structure, build up by primary particles (such as inorganic nanocrystals or polymers), provide these materials with unique physical properties and high specific surface areas. While the library of cryogels is endless, widely used in the polymer chemistry field, in this review we will summarize the structure and properties, applications and challenges of inorganic nanocrystal-based cryogels obtained by freezing and freeze-drying an aqueous nanoparticle colloid. This fast, easy and versatile gelation method will be outlined, along with the corresponding macro-, micro- and nano-structures and gel morphologies that can be obtained, for example, by changing the freezing temperature or by using one nanoparticle system or nanoparticle mixtures. Their applications towards electrocatalysis, photocatalysis and photoelectrochemical sensing will be highlighted, as well as the challenges and prospects of these materials.

Molecular self-assembly becomes an attractive strategy for the preparation of anisotropic colloidal particles that inherit the properties of molecules in single states and the new functions resulting from the coupling between molecules. This article reviews the recent progress towards molecular self-assembly of anisotropic colloids, focusing on molecular self-assembly strategies and their applications.

Abstract

Anisotropic colloidal particles have attracted great attention over the past few decades because of their significant properties that differ from isotropic particles. Molecular self-assembly provides the possibility to design and construct anisotropic colloidal particles from the single-molecule level, and molecular assemblies can both inherit the properties of molecules in single states and integrate the functions of molecules in collective states, which has attracted great interest to researchers. Even in recent years, the self-assembly strategy of anisotropic colloidal particles has been greatly developed. This review article briefly summarizes the research progress of molecules from small molecules, block copolymers and homopolymers to anisotropic particles, including their self-assembly strategies and applications. Finally, we discuss the remaining challenges of this topic and we expect that by manipulating the design of diverse molecules/polymers, anisotropic colloidal particles can evolve into a new era.

Novel water-soluble nanocomposite based on hydrophobic tetraphenylporphyrin molecules and hydrophilic ternary AgInS₂/ZnS quantum dots incorporated into a chitosan matrix was fabricated for applications in antibacterial photodynamic therapy. The enhanced singlet oxygen generation by the formed nanocomposites can be observed due to the efficient resonance energy transfer from ternary quantum dots to tetraphenylporphyrin molecules.

Abstract

Antibacterial photodynamic therapy (a-PDT) has emerged as a promising non-invasive therapeutic modality that utilizes the combination of a photosensitive agent, molecular oxygen, and excitation light to generate reactive oxygen species (ROS), demonstrating remarkable activity against multidrug-resistant bacterial infections. However, the effective use of conventional photosensitizers is significantly limited by a number of their shortcomings, namely, poor water solubility and low selectivity. Herein, we present a novel biocompatible water-soluble nanocomposite based on hydrophobic tetraphenylporphyrin (TPP) molecules and hydrophilic ternary AgInS₂/ZnS quantum dots incorporated into a chitosan matrix as an improved photosensitizer for a-PDT. We demonstrated that TPP molecules could be successfully transferred into chitosan solution while remaining primarily in the form of monomers, which are capable of singlet oxygen generation. We performed a detailed analysis of the Förster resonance energy transfer (FRET) between quantum dots and TPP molecules within the nanocomposite and proposed the mechanism of the singlet oxygen efficiency enhancement via FRET.

A self-assemble N-doped graphene and N-doped carbon nanoparticles integrated composite has been prepared by a multi-step acid etching plus annealing method. The formation of N-doped graphene is likely based on a “decomposition and recrystallization” mechanism without the use of any metallic catalyst. The as-prepared integrated composite exhibits efficient catalytic activity for four-electron oxygen reduction reaction.

Abstract

N-doped carbon-based materials have been regarded as promising alternatives to Pt-based electrocatalysts for the four-electron (4e⁻) oxygen reduction reaction (ORR), which is an important electrochemical reaction for the polymer electrolyte fuel cells. Here, we report a N-doped graphene and N-doped carbon nanoparticles integrated composite electrocatalyst by a multi-step acid etching plus annealing method. Despite the low N-doping level, the material exhibits efficient 4e⁻ ORR activity with an onset potential of 0.932 V, a half-wave potential of 0.814 V, and a limiting current density of 5.3 mA cm⁻² in 0.1 M KOH solution. We demonstrate that the promoted 4e⁻ ORR activity is attributed to the special 2D–0D integrated structure for exposing massive active sites, the favorable porous structure facilitating the H₂O transfer dynamics, and the high content of oxygen-containing C−O−C species and the increased intrinsic carbon defects for additional active sites. A “decomposition and recrystallization” mechanism is proposed for the formation of N-doped graphene.