Heterogeneous Nanosheets Research Articles

A novel nano‐cotton‐like bismuth oxyfluoride (NC‐BiOF) and a novel nanosheet heterogeneous compound BiOF@ZIF‐8 as catalyst for the selective and green oxidation of benzylic alcohols

We describe here for the first time a new morphology of BiOF nanoparticles with a cotton‐like structure, made using a hydrothermal synthesis method. We also prepared heterogeneous nanosheets of BiOF@ZIF‐8 by a one‐pot synthesis under hydrothermal conditions. We demonstrate that in this method the morphology of BiOF and one‐pot synthesis conditions are the main factors for the preparation of the nanosheet BiOF@ZIF‐8. Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), thermogravimetry‐differential thermal analysis (TG‐DTA), and BET surface area were used to characterize the samples prepared. XRD, SEM, and adsorption–desorption analysis showed that the structure of ZIF‐8 and BiOF form intact only in one‐pot synthesis of BiOF (with nano‐cotton‐like morphology) with Zn(NO3)3, while spectral techniques show the successful encapsulation of the sheet BiOF on ZIF‐8. Nanosheet BiOF@ZIF‐8 was found to be a highly efficient heterogeneous catalyst for the selective oxidation of alcohols. BiOF@ZIF‐8 could be reused several times although it got less active with recycling.

Heterogeneous interface engineered atomic configuration on ultrathin Ni(OH)2/Ni3S2 nanoforests for efficient water splitting

The sluggish water dissociation kinetics of low-cost Ni3S2 electrocatalysts severely hinders the hydrogen evolution reaction (HER), resulting in unsatisfied overall water splitting in alkaline media. Herein, we demonstrate the self-assembly of a new nanoforest electrocatalyst by ultrathin Ni(OH)2/Ni3S2 heterogeneous nanosheets (∼1.8 nm) using a high-temperature and large-potential electrodeposition technique. The surface atomic configuration of Ni3S2 is well-modulated by hetero-interface engineering with the Ni(OH)2 cocatalyst, effectively accelerating the Volmer step and OH− adsorption during the HER without sacrificing the oxygen evolution reaction (OER). The resultant electrocatalysts exhibit superior and stable electrocatalytic activity toward the HER and OER in 1 M KOH with small overpotentials of 50 mV and 210 mV at 10 mA cm-2, respectively. Using the Ni(OH)2/Ni3S2 nanoforest as dual-functional electrocatalysts, an alkaline electrolyzer can render 100 mA cm-2 at a very low cell voltage of 1.64 V while keep stable for 120 h at 1.55 V, which outperforms the best report for Ni-based electrocatalysts. This finding gives a new insight into the modulating surface atomic configuration for achieving highly active electrocatalysts for water splitting.

A "uniform" heterogeneous photocatalyst: integrated p-n type CuInS2/NaInS2 nanosheets by partial ion exchange reaction for efficient H2 evolution.

Single-crystalline-like P-N type CuInS2/NaInS2 heterogeneous nanosheets were synthesized by partial cation exchange reaction and show highly improved photocatalytic H2 evolution activity attributed to the increased efficiency of interfacial charge transfer.