(338d) Core-Shell Ferrite Nanoparticles for Hydrogen Production From Thermochemical Water-Splitting Process

Hydrogen can be efficiently produced by the two-step thermochemical water splitting process which involves partial reduction of redox materials (e.g. ferrites) at elevated temperatures creating oxygen vacancies followed by oxidation of partially reduced redox material at lower temperatures leading to oxygen scavenging from steam and producing hydrogen. We report the sol-gel synthesis of core-shell nanoparticles of different ferrite materials which include nickel, manganese, zinc and cobalt ferrites. As prepared gel was aged for 48 hours and dried at about 100 ^oC for 2 hours and calcined at 800 ^oC. These core-shell nano particles were analyzed by Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET), X-Ray Diffraction (XRD) to understand core-shell morphology, specific surface area and phase formation, respectively. The core-shell nanoparticles were loaded inside a tubular reactor as a packed bed with supporting material and heated to 700 to 1100 ^oC under the constant nitrogen flow rate of 35 to 100 sccm. After the activation step, water was introduced at 500 ^oC and the hydrogen in the product gas stream was continuously monitored using the online hydrogen sensor interfaced with a computer. Multiple thermochemical cycles were performed and the hydrogen volume generated for the ferrite core-shell nanoparticles was compared with ferrite nanoparticles. After the thermochemical cycles, the powdered material was recovered and analyzed by SEM/TEM, XRD, and BET. The results on the hydrogen volume generation obtained using ferrite core-shell nanoparticles will be presented.