Construction of Sn–Mo bimetallic oxide nanoparticle-encapsulated P-doped 3D hierarchical porous carbon through an in-situ reduction and competitive cross-linking strategy for efficient pseudocapacitive energy storage

A review of physical, chemical and biological synthesis methods of bimetallic nanoparticles and applications in sensing, water treatment, biomedicine, catalysis and hydrogen storage

This article provides an in-depth analysis of various fabrication methods of bimetallic nanoparticles (BNP), including chemical, biological, and physical techniques. The review explores BNP's diverse uses, from well-known applications such as sensing water treatment and biomedical uses to less-studied areas like breath sensing for diabetes monitoring and hydrogen storage. It cites results from over 1000 researchers worldwide and >300 peer-reviewed articles. Additionally, the article discusses current trends, actionable recommendations, and the importance of synthetic analysis for industry players looking to optimize manufacturing techniques for specific applications. The article also evaluates the pros and cons of various fabrication methods, highlighting the potential of plant extract synthesis for mass production of capped BNPs. However, it warns that this method may not be suitable for certain applications requiring ligand-free surfaces. In contrast, physical methods like laser ablation offer better control and reactivity, especially for applications where ligand-free surfaces are critical. The report underscores the environmental benefits of plant extract synthesis compared to chemical methods that use hazardous chemicals and pose risks to extraction, production, and disposal. The article emphasizes the need for life cycle assessment (LCA) articles in the literature, given the growing volume of research on nanotechnology materials. This article caters to researchers at all stages and applies to various fields applying nanomaterials.

Hollow nanotube arrays of nickle-cobalt metal sulfide for high energy density supercapacitors

High energy density is still difficult to achieve using existing metal sulfides because of their low specific capacitance. To improve capacitance, a series of nickel and cobalt metal sulfides with different Ni/Co ratios were synthesized by a two-step hydrothermal method. Using the combining method of experimental research and first-principles calculation, the morphology, structural stability, electronic structure and electrochemical properties of metal sulfides were investigated systematically. The results show that the morphology of metal sulfides gradually grows from two-dimensional structure to nanotube arrays, and finally to nanorod arrays, as the Ni/Co ratios decrease. Among them, the NC24 sample with the Ni/Co ratio of 1 : 2 is a hollow nanotube array composed of NiCo₂S₄, which shows excellent electrochemical performance. The specific capacity of the NC24 sample reaches 1527C g^-1 at 1 A g^-1, and the capacity retention is 93.81% at 10 A g^-1 after 2000 cycles. Furthermore, a symmetrical supercapacitor assembled from the NiCo₂S₄ nanotube array shows a high energy density of 67.5 W h kg^-1. This strategy develops a nanotube array of metal sulfides and expands its application in a high energy density supercapacitor.

B,N-Codoped Porous C with Controllable N Species as an Electrode Material for Supercapacitors

Manufacturing heteroatom-doped porous C with controllable N species is an important issue for supercapacitors. Herein, we report a low-cost and simplified strategy for synthesizing B,N-codoped porous C (BNPC) by a freeze-drying chitosan-boric acid aerogel beads and subsequent carbonization treatment. The BNPC samples were studied using various characterization technologies. The introduction of boric acid to chitosan successfully induced the formation of B,N-codoped C with a well-developed 3D interconnected porous structure. The B doping had a significant impact on the distribution of N species in the samples. Moreover, the good wettability of the sample resulting from B doping is favorable for electrolyte diffusion and ion transport. As a consequence, the optimal BNPC sample showed an excellent specific capacitance of 240 F g^-1 at 0.5 A g^-1 and an outstanding capacitance retention of 95.1% after 10000 cycles at 5 A g^-1. An assembled symmetrical supercapacitor displayed an energy density of 11.4 Wh kg^-1 at a power density of 250 W kg^-1. The proposed work provides a simple and effective method to obtain B,N-codoped C-based materials with high electrochemical performance.