Fukun Ma

Novel carbon dots/BiOBr nanocomposites with enhanced UV and visible light driven photocatalytic activity

Novel UV and visible light photocatalytic carbon dots/BiOBr nanocomposites were prepared for the first time. The structures, morphologies, optical, photoelectrochemical and photocatalytic properties were investigated. The results indicated that the carbon dots (CDs) combined well with BiOBr. An appropriate amount of introduced CDs can significantly enhance the photocatalytic activities under both UV and visible light irradiation. The enhanced activities were mainly attributed to the enhanced light absorption and the interfacial transfer of photogenerated electrons. The corresponding photocatalytic mechanism was proposed based on the results.

One-step exfoliation and fluorination of g-C3N4 nanosheets with enhanced photocatalytic activities

Exfoliation and functionalisation of two-dimensional (2D) nanosheets are highly desired for the improvement of their chemical and physical properties. Herein, we propose a novel and efficient method for the preparation of fluorinated graphite carbon nitride (F-C3N4) nanosheets with enhanced photocatalytic activities. A one-step route was used to exfoliate and fluorinate the graphite carbon nitride (g-C3N4) nanosheets by using g-C3N4 powder combined with ammonium fluoride (NH4F). Through related instrumental characterisation, we confirmed that few-layered F-C3N4 nanosheets were produced successfully. Meanwhile, the enhanced hydrogen evolution rate of F-C3N4 nanosheets (477.6 µmol h−1 g−1) also confirmed the feasibility of this exfoliation method. This report not only opens up new possibilities for the rational design of metal-free F-C3N4 nanosheets with stable photochemical applications but also provides a potential method for producing functionalised 2D materials.

‘Thermal substitution’ for preparing ternary BCN nanosheets with enhanced and controllable nonlinear optical performance

Boron carbon nitride (BCN) nanosheets have gained increased attention as a novel semiconductor because of their controllable band-gap and environmentally-friendly properties. This study presents a facile ‘thermal substitution’ method for preparing BCN nanosheets through substitutional C doping into hexagonal boron nitride nanosheets (BNNSs) at 850 °C. ‘Thermal substitution’ is an effective method used to tune the band-gap of BCN nanosheets by adjusting the amount of carbon atoms incorporated. After irradiation by laser pulses at 1064 and 532 nm, the as-obtained BCN nanosheets exhibit excellent nonlinear optical (NLO) performance. The NLO absorption properties of the nanosheets shift from saturable absorption to reverse saturable absorption. The corresponding NLO performance can be adjusted by controlling the carbon content in the BCN nanosheets. The developed BCN nanosheets can be utilised as a new and advanced NLO material for sensitive optical components and laser protection.

Fabrication of CdS/BNNSs nanocomposites with broadband solar absorption for efficient photocatalytic hydrogen evolution

In this study, the nanocomposites of cadmium sulfide (CdS) nanoparticles and hexagonal boron nitride nanosheets (BNNSs) were fabricated through in situ growing of CdS nanoparticles on BNNSs. The microstructure of the nanocomposites was clearly demonstrated. Compared with pure CdS nanoparticles, CdS/BNNSs nanocomposites show more efficient photocatalytic H2 production. The rate of H2 evolution can be doubled under the optimum conditions. The enhancement of photocatalytic H2 evolution is attributed to the ultrathin BNNSs. It is speculated that the BNNSs not only broaden the photo-absorption region, but also realized effective electronic communication through the connection between CdS nanoparticles and BNNSs. This new finding provides a promising way to design and fabricate more efficient photocatalysts based on BNNSs.

Metal-free Ternary BCN Nanosheets with Synergetic Effect of Band Gap Engineering and Magnetic Properties

Introducing the synergy effect of magnetic properties and band gap engineering is highly desired for two-dimensional (2D) nanosheets. Here, we prepare metal-free ternary 2D carbon (C) doped boron nitride (BN) nanosheets (BCN) with band gap engineering and magnetic properties by a synergetic way. The substitutional occupation of C atoms, as revealed by X-ray absorption spectrum, in BCN nanosheets induces tunable band gap reduction (5.5 eV to 2.6 eV) and intensive intrinsic ferromagnetism at room temperature. First-principle calculations also reveal that substituted C atoms in BCN nanosheets can broaden the light adsorption region and reduce the optical band gap, and ferromagnetic ordering is energetically more favorable than antiferromagnetic. This design opens up new possibility for synergetic manipulation of exchange interactions and band gap engineering in 2D nanostructures.

Band gap-Tunable Porous Borocarbonitride Nanosheets for High Energy-Density Supercapacitors

Band gap-tunable porous borocarbonitride (BCN) nanosheets were successfully fabricated with cheap and readily available precursors by annealing and exfoliating. The band gap of the as-prepared BCN materials ranges from 5.5 to 1.0 eV; these samples exhibit beneficial structural features suitable for the application in supercapacitors. Especially, the BCN material with a band gap of 1.0 eV exhibits a great specific surface area (600.9 m2 g-1), massive active sites, and excellent conductivity (10.8 S m-1). In addition, this example displays great specific capacitance (464.5 F g-1), excellent cycle stability (98.5% performance retention after 10 000 cycles), and ultrahigh energy density (50.4 W h kg-1, in 1 M Et4NBF4 electrolyte). This excellent electrochemical performance and facile effective synthesis of band gap-tunable BCN materials will provide a promising strategy for configuring nanostructured multiple compound electrodes for other energy storage and conversion devices.