Single-wall carbon carcass nanoparticles (nanohorns) (CNHs) are synthesized by two methods: electric arc and electron evaporation of graphite in the inert atmosphere. Distinctions in the structures of obtained materials are revealed using electron microscopy and Raman spectroscopy. The chemical structure of the CNH surface is investigated by X-ray photoelectron and NEXAFS spectroscopy during oxidation. It is found that oxidation causes the destruction of CNH agglomerates and weakly affects the structure of graphene nets. However, these changes are sufficient for an increase in the infrared radiation absorption by the dispersion of nanohorns in water. It is shown that the efficiency of 808 nm laser heating of a CNH dispersion depends on the synthesis method and chemical modification of nanoparticles, which enables their potential use for local hyperthermia of cells of living organisms in cancer therapy.