A multi-interfacial FeOOH@NiCo2O4 heterojunction as a highly efficient bifunctional electrocatalyst for overall water splitting.

Electrocatalytic water decomposition is the key to sustainable energy, and the design and synthesis of cost-effective electrocatalysts is the main objective of electrocatalytic water splitting. In this paper, multi-interfacial FeOOH@NiCo2O4 hybrid nanoflowers are prepared through a two-step hydrothermal reaction. In such heterostructures, NiCo2O4 nanoflowers are coated with a layer of FeOOH nanoparticles. In addition, the obtained electrocatalyst could provide abundant electroactive sites and the formation of FeOOH@NiCo2O4 nanointerfaces can also improve the charge transfer rate. As a result, under the HER and OER conditions, the prepared catalysts show an outstanding electrocatalytic performance. Moreover, in a two-electrode water splitting system, the FeOOH@NiCo2O4 heterostructure, as a dual-function electrocatalyst, needs a cell voltage of only 1.58 V at a current density of 10 mA cm-2. This study provides a facile and feasible method to construct different kinds of heterostructures as bifunctional electrocatalysts with multiple interfaces by a simple hydrothermal method.

Facile one-pot synthesis of novel hierarchical Bi2O3/Bi2S3 nanoflower photocatalyst with intrinsic p-n junction for efficient photocatalytic removals of RhB and Cr(VI).

The construction of heterojunction system can promote the separation and transfer of photogenerated electron-hole pairs, which is conducive to the degradation of sewage. In this paper, heterostructured Bi2O3/Bi2S3 nanoflowers are fabricated by a one-step hydrothermal method. The microstructure and optical absorption properties are studied through the detailed characterization of this heterojunction. The visible light photocatalytic ability of as-prepared Bi2O3/Bi2S3 heterojunctions are investigated by photocatalytic removals of RhB and Cr(VI). The results of photocatalysis indicate that removal efficiencies of RhB and Cr(VI) over Bi2O3/Bi2S3 heterojunction are higher than those of pure Bi2O3 and Bi2S3. The improved photocatalytic performance of the Bi2O3/Bi2S3 heterojunctions could be attributed to a combination of the p-n junction between the p-type Bi2S3 and n-type Bi2O3, and large specific surface areas (46.31 m2 g-1). Moreover, the probable photocatalytic mechanism of composite photocatalysts is explored in detail by active species trapping experiments, N2 adsorption-desorption, the transient photovoltage electrochemical impedance spectroscopy and photoluminescence measurements. This work provides new insights into building of the efficient and novel heterogeneous photocatalysts and other energy-related devices.