Abstract: Provided are methods of producing cobalt nanoparticles (Co NPs). The methods include combining a cobalt salt, a capping agent, and a reducing agent, under Co NP synthesis conditions including a temperature selected to produce cobalt nanoparticles of a pre-selected diameter, where the temperature and pre-selected diameter are inversely related. In certain aspects, the methods further include producing hollow gold nano spheres (HGNs) using the cobalt nanoparticles as scaffolds. Also provided are cobalt nanoparticles and hollow gold nano spheres (HGNs) produced according to the present methods. Kits that find use in practicing the methods of the present disclosure are also provided.

Abstract: Provided are methods of producing hollow metal nanospheres (HMNs) having a pre-selected surface rugosity. The methods include combining in a galvanic exchange reaction at a selected pH: a solution comprising cobalt-based nanoparticle (CoxBy NP) scaffolds; and a solution comprising a metal, to produce CoxBy NP core/metal shell structures. The methods further include oxidizing the CoxBy NP cores of the CoxBy NP core/metal shell structures to produce HMNs having the pre-selected surface rugosity, where the pH of the galvanic exchange reaction is selected to produce the pre-selected surface rugosity of the HMNs. Also provided are HMNs produced according to the methods, as well as methods of using the HMNs. Compositions and kits that find use, e.g., in practicing the methods of the present disclosure, are also provided.

Abstract: Provided are methods of producing cobalt-based nanoparticles (CoxBy NPs) of a pre-selected diameter. The methods include reducing Co2+ ions with a sodium borohydride (NaBH4) solution having a selected ratio of tetrahydroxyborate (B(OH)4?) to tetrahydroborate (BH4?) based on the pre-selected diameter, where the ratio of B(OH)4? to BH4? is positively correlated with the pre-selected diameter. Also provided are methods of using the CoxBy NPs to produce hollow metal nanospheres (HMNs). Methods of producing CoxBy NP core/metal shell structures are also provided, such methods including combining in an anaerobic galvanic exchange reaction a deaerated solution including CoxBy NP scaffolds and a deaerated solution including a metal. Also provided are methods of producing HMNs from the CoxBy NP core/metal shell structures. Compositions and kits that find use in practicing the methods of the present disclosure and using HMNs produced in accordance with the methods of the present disclosure, are also provided.

Abstract: Provided are methods of producing cobalt nanoparticles (Co NPs). The methods include combining a cobalt salt, a capping agent, and a reducing agent, under Co NP synthesis conditions including a temperature selected to produce cobalt nanoparticles of a pre-selected diameter, where the temperature and pre-selected diameter are inversely related. In certain aspects, the methods further include producing hollow gold nano spheres (HGNs) using the cobalt nanoparticles as scaffolds. Also provided are cobalt nanoparticles and hollow gold nano spheres (HGNs) produced according to the present methods. Kits that find use in practicing the methods of the present disclosure are also provided.