We synthesized a unique carbon nanosphere (CNS)encapsulated Fe core−shell catalyst (CNS−Fe) for CO 2 hydrogenation. The synthesized CNS−Fe catalyst exhibited a core−shell structure with a core of ca. 40 nm containing iron species and a shell thickness of ca. 10 nm composed of mainly graphitic carbon. X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and thermogravimetric analysis were used to characterize the fresh and spent CNS−Fe catalysts and reveal a mixture of Fe 3 O 4 , metallic Fe, and Fe 5 C 2 in the core and graphitic carbon as the shell with defect sites. Hydrogen temperature-programmed reduction, X-ray absorption near-edge structure, and extended X-ray absorption fine structure for the fresh CNS−Fe confirmed the composition of the iron species encapsulated in the CNS. The catalytic performance of CNS−Fe was investigated at ambient pressure for CO 2 hydrogenation with hydrocarbons (CH 4 , C 2 −C 4 = , C 2 −C 4 0 ), and CO was observed as the main product.

Electrospinning is a straightforward technique for the fabrication of nanofibers with the potential for various applications. Thermal energy storage systems using electrospun nanofibers have gained researchers’ attention due to its desirable properties such as nanoscale diameter, large surface area, excellent thermal conductivity, and high loading and thermal energy storage capacity. The encapsulation of phase change materials (PCMs) in electrospun nanofibers for storing renewable thermal energy can be achieved by uniaxial electrospinning of a blend of PCM and polymer, coaxial electrospinning of a PCM core and a polymer sheath, or post-electrospinning absorption. The PCM content and thermal energy storage capacity of different PCM composite nanofibers are compared in this chapter. The drawbacks of traditional electrospinning PCM encapsulation techniques and benefits of post-electrospinning encapsulation methods are discussed.