Biomass-Templated Preparation of Multifunctional Ni/NiO@C Hollow-Fiber Hierarchical Composite Materials

Here, two Ni/NiO@C hollow-fiber composites were created, exhibiting magnetic, adsorbent, and electrocatalytic (OER/HER) properties. Our approach was a straightforward, eco-friendly, two-step dipping/adsorbing-calcining method, using Ni(NO3)2·6H2O and biomass cotton fiber (CF) as starting materials. We then thoroughly characterized the resulting materials using a suite of techniques, including SEM, TEM, XRD, BET, and XPS, to get a good handle on their properties. The morphology, composition, and properties of synthesized materials were analyzed relative to the calcination temperature and carbon fiber (CF) content. The findings reveal that, when maintained at an optimal temperature, a specific quantity of CF introduced serves multiple functions: it acts as a structural template, imparting a hollow-fiber hierarchical morphology to the resulting materials, while also facilitating the reduction of Ni2+ to Ni0 through carbonization. Additionally, it supplies carbon, enabling the formation of multicomponent materials composed of Ni0, NiO, and C. These materials really shine due to their magnetic nature, their ability to soak up other substances, and their knack for speeding up electrical reactions. They are particularly good at both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), which makes them a killer combo for splitting water into its basic elements. The unique layered structure and cooperative action of Ni0 and NiO significantly improve the synthesized material’s performance in both the OER and HER. Notably, this preparation method is affordable, straightforward, and sustainable and has an abundant, renewable template source.