| Autor: |
Sachin Kumar B; Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Mangalore 575025, India. anandtmg@gmail.com., Tarafder K; Department of Physics, National Institute of Technology Karnataka, Mangalore 575025, India., Shetty AR; Department of Chemistry, National Institute of Technology Karnataka, Mangalore 575025, India., Hegde AC; Department of Chemistry, National Institute of Technology Karnataka, Mangalore 575025, India., Gudla VC; Section of Materials and Surface Technology, Department of Mechanical Engineering, Technical University of Denmark, Produktionstorvet, Dk-2800 Kgs. Lyngby, Denmark., Ambat R; Section of Materials and Surface Technology, Department of Mechanical Engineering, Technical University of Denmark, Produktionstorvet, Dk-2800 Kgs. Lyngby, Denmark., Kalpathy SK; Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, India., Anandhan S; Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Mangalore 575025, India. anandtmg@gmail.com. |
| Abstrakt: |
Producing pure H 2 and O 2 to sustain the renewable energy sources with minimal environmental damage is a key objective of photo/electrochemical water-splitting research. Metallic Ni-based electrocatalysts are expensive and eco-hazardous. This has rendered the replacement or reduction of Ni content in Ni-based electrocatalysts a decisive criterion in the development of bifunctional electrocatalytic materials. In the current study, spinel/ilmenite composite nickel titanate (NTO) nanofibers were synthesised using sol-gel assisted electrospinning followed by pyrolysis at different soaking temperatures (viz., 773, 973, and 1173 K). The presence of a defective spinel NTO phase (SNTO) distributed uniformly along the nanofibers was confirmed by X-ray photoelectron and Raman spectroscopy. The electron micrographs revealed the morphological change of NTO nanofibers from a mosaic to bamboo structure with an increase in pyrolysis soaking temperature. The electrocatalytic activity of NTO nanofibers obtained at different pyrolysis soaking temperatures for alkaline water-splitting was studied. The highly defective SNTO manifests properties similar to metallic Ni and favours H 2 evolution through the hydrogen evolution reaction (HER) by adsorbing more H + ions on active sites. In contrast, the ilmenite NTO favours O 2 discharge. These results are explained based on the morphology of the NTO nanofibers. The mosaic structure which has higher porosity and greater SNTO content shows excellent HER performance. In contrast, the large bamboo structured NTO nanofibers which have lesser porosity and SNTO content cage the bigger (OH) ads ions at their catalytic sites to facilitate OER performance. |
