A Facile Synthesis of Ternary Nickel Iron Sulfide Nanospheres as Counter Electrode in Dye-Sensitized Solar Cells

Emergence of Ni-Based Chalcogenides (S and Se) for Clean Energy Conversion and Storage

Nickel chalcogenide (S and Se) based nanostructures intrigued scientists for some time as materials for energy conversion and storage systems. Interest in these materials is due to their good electrochemical stability, eco-friendly nature, and low cost. The present review compiles recent progress in the area of nickel-(S and Se)-based materials by providing a comprehensive summary of their structural and chemical features and performance. Improving properties of the materials, such as electrical conductivity and surface characteristics (surface area and morphology), through strategies like nano-structuring and hybridization, are systematically discussed. The interaction of the materials with electrolytes, other electro-active materials, and inactive components are analyzed to understand their effects on the performance of energy conversion and storage devices. Finally, outstanding challenges and possible solutions are briefly presented with some perspectives toward the future development of these materials for energy-oriented devices with high performance.

Continuous-Flow Separation and Efficient Concentration of Foodborne Bacteria from Large Volume Using Nickel Nanowire Bridge in Microfluidic Chip

Separation and concentration of target bacteria has become essential to sensitive and accurate detection of foodborne bacteria to ensure food safety. In this study, we developed a bacterial separation system for continuous-flow separation and efficient concentration of foodborne bacteria from large volume using a nickel nanowire (NiNW) bridge in the microfluidic chip. The synthesized NiNWs were first modified with the antibodies against the target bacteria and injected into the microfluidic channel to form the NiNW bridge in the presence of the external arc magnetic field. Then, the large volume of bacterial sample was continuous-flow injected to the channel, resulting in specific capture of the target bacteria by the antibodies on the NiNW bridge to form the NiNW–bacteria complexes. Finally, these complexes were flushed out of the channel and concentrated in a lower volume of buffer solution, after the magnetic field was removed. This bacterial separation system was able to separate up to 74% of target bacteria from 10 mL of bacterial sample at low concentrations of ≤10² CFU/mL in 3 h, and has the potential to separate other pathogenic bacteria from large volumes of food samples by changing the antibodies.

Mesoporous NiCo2O4 nanoflower constructed from nanosheets as electroactive materials for dye-sensitized solar cells

Binary metal compounds with a spinel structure could improve the electron transport, activating adsorption and active sites for electrocatalytic reaction. Furthermore, the electrocatalytic activity of electroactive materials also depends on their morphology and nanostructure. Herein, this work reported the fabrication of NiCo₂O₄ mesoporous nanoflowers and mesoporous nanospheres and their application as promising counter electrode (CE) electrocatalysts in dye-sensitized solar cells (DSSCs). The as-prepared NiCo₂O₄ mesoporous nanoflower contains abundant open space between nanosheets, generating the 3D porous nanostructure. When investigated as CE materials, NiCo₂O₄ nanoflowers exhibited high charge-transfer ability and intrinsic catalytic activity. The DSSC with NiCo₂O₄ nanoflowers displayed a much higher power conversion efficiency (PCE) of 7.32% than that based on the NiCo₂O₄ nanosphere CE (PCE = 5.58%), even comparable with that of commercial Pt CE (7.54%).

Mesoporous NiCo₂O₄ nanoflower constructed form nanosheets was successfully fabricated and showed efficient electrocatalytic performance as electroactive materials for dye-sensitized solar cells.