Catalyst-free one step synthesis of large area vertically stacked N-doped graphene-boron nitride heterostructures from biomass source

Boron, nitrogen co-doped biomass-derived carbon aerogel embedded nickel-cobalt-iron nanoparticles as a promising electrocatalyst for oxygen evolution reaction

The electrocatalytic performance of oxygen evolution reaction (OER) electrocatalysts is highly reliant on the activity of its catalytic active site, which may be augmented by raising the number of active sites. In this study, nanoscaled nickel-cobalt-iron (NiCoFe) alloy was embedded on conductive boron(B), nitrogen(N) co-doped/biomass-derived carbon aerogel as an OER electrocatalyst. The synthesized electrocatalysts were calcined under different temperatures and with variable dopants. The optimal electrocatalyst (BN/CA-NiCoFe-600) demonstrated a low overpotential of 321 mV (at current density of 10 mA cm^-2) and a minute Tafel slope of 42 mV dec^-1, which was even smaller than that of IrO₂ and RuO₂. Its mass activity and specific activity were calculated to be 201.7 A g^-1, and 34.1 cm^-2_ECSA, respectively. Furthermore, the electrocatalyst showed excellent stability and durability. This work provides an easy and practical synthetic strategy for acquiring very active and durable electrocatalysts for OER.

Compressive and thermally stable boron nitride aerogels as multifunctional sorbents

Boron nitride (BN) aerogels are three-dimensional bulk materials with exceptional performances in a wide range of areas. However, detailed investigations into the relationship of synthesis, structure, and properties are rare. This study demonstrates the feasibility of tuning the performance of the aerogel by simply altering the relative amount of the precursors in the synthesis, which subsequently leads to the formation of aerogels with distinctive properties such as specific surface areas, porosity, and compressibility. The applications of these structurally different aerogels are exemplified by investigating in a series of important industrial-related areas, such as oil absorption/desorption, direct combustion, adsorptive desulfurisation, and CO₂ capture. The study raises the application prospects of BN aerogels in gas-phase catalysis and thermal superinsulation materials.

Design, Fabrication, and Mechanism of Nitrogen-Doped Graphene-Based Photocatalyst

Solving energy and environmental problems through solar-driven photocatalysis is an attractive and challenging topic. Hence, various types of photocatalysts have been developed successively to address the demands of photocatalysis. Graphene-based materials have elicited considerable attention since the discovery of graphene. As a derivative of graphene, nitrogen-doped graphene (NG) particularly stands out. Nitrogen atoms can break the undifferentiated structure of graphene and open the bandgap while endowing graphene with an uneven electron density distribution. Therefore, NG retains nearly all the advantages of original graphene and is equipped with several novel properties, ensuring infinite possibilities for NG-based photocatalysis. This review introduces the atomic and band structures of NG, summarizes in situ and ex situ synthesis methods, highlights the mechanism and advantages of NG in photocatalysis, and outlines its applications in different photocatalysis directions (primarily hydrogen production, CO₂ reduction, pollutant degradation, and as photoactive ingredient). Lastly, the central challenges and possible improvements of NG-based photocatalysis in the future are presented. This study is expected to learn from the past and achieve progress toward the future for NG-based photocatalysis.

A Chemical Blowing Strategy to Fabricate Biomass-Derived Carbon-Aerogels with Graphene-Like Nanosheet Structures for High-Performance Supercapacitors

The efficient exploitation and utilization of low-cost and biomass-derived carbon materials will play an active role in developing sustainable energy storage systems. However, the difficult morphology control and incomplete activation limits their pervasive application in electrochemical energy storage. Inspired by the famous Chinese folk handicraft of sugar-figure blowing, biomass-derived carbon aerogels (GCA) with 2 D graphene-like thin nanosheets were fabricated by a simple chemical blowing strategy from a viscous agaric solution obtained through hydrothermal treatment of agaric. A chemical blowing agent (NH₄ Cl) was used to effectively exfoliate the bulk biomass-derived carbon flake into 2 D graphene-like nanosheets, which resulted in a highly porous structure and high specific area (2200 m²  g^-1 ) after the activation process. As a result, a high specific capacitance of 340 F g^-1 at 3 A g^-1 and a high specific energy of 25.5 Wh kg^-1 at a power density of 2 kW kg^-1 was obtained for the GCA electrode, which can be attributed to the abundant electrochemically active surfaces, short ion transport paths, and effective electrolyte infiltration.. This work demonstrates an effective and low-cost strategy to prepare hierarchical and well-organized porous biomass carbon materials with graphene-like nanosheets for high-performance supercapacitors.

A reliable procedure for the preparation of graphene-boron nitride superlattices as large area (cm × cm) films on arbitrary substrates or powders (gram scale) and unexpected electrocatalytic properties

Herein, a reliable procedure for the preparation of graphene-boron nitride superlattices, either as films or powders, consisting of the pyrolysis at 900 °C of polystyrene embedded pre-formed boron nitride single sheets is reported. The procedure can serve to prepare large area films (cm × cm) of this superlattice on quartz, copper foil and ceramics. Selected area electron diffraction patterns at every location on the films show the occurrence of the graphene-boron nitride superlattice all over the film. The procedure can also be applied to the preparation of powdered samples on a gram scale. Comparison with other materials indicates that the superlattice appears spontaneously as the growing graphene sheets develop, due to the templating effect of pre-existing boron nitride single sheets. Since the characteristic boron nitride emission in the visible region is completely quenched in the superlattice configuration, it is proposed that fluorescence microscopy can be used as a routine technique to determine the occurrence of superlattice in large area films. Electrodes of this material show an unforeseen catalytic activity for oxygen reduction reaction and exhibit a decrease of the heterojunction-electrolyte interphase electrical resistance.