Thermochemical Hydrogen Production From Water-Splitting Process Using Core-Shell Ferrite Nanoparticles

Thermochemical Hydrogen Production from Water-Splitting Process Using Core-Shell Ferrite Nanoparticles 
S. Yelakanti, J. A. Puszynski, R. V. Shende*
South Dakota School of Mines and Technology, SD, USA

 Abstract

Worldwide a majority of energy demand is currently fulfilled by the use of fossil fuels. As a result, consumption of fossil fuel is increasing day by day leading to depletion of fossil fuels and greenhouse gas emission. To address these issues, hydrogen can be utilized as a partial replacement of fossil fuels. Among several existing H₂ production technologies, a two-step thermochemical water-splitting process, which utilizes redox materials is considered as one of the green H₂ production technologies. In this investigation, we synthesized several redox materials using sol-gel approach and utilized for H₂ generation in multiple thermochemical cycles. Among different materials prepared and tested, Ni-ferrite produced highest H₂ volume at water-splitting and regeneration temperatures of 700^o and 1100^oC, respectively.  Our group has recently performed 125 thermochemical cycles using sol-gel derived ferrites and achieved higher H₂ volume as compared with that reported for ceria based redox materials at 800^o-1600^oC. We observed that when ferrite materials undergo thermochemical cycling process, grain growth and sintering occur that decrease surface area and generate less H₂. We believe that if ferrite materials are thermally stabilized, less grain growth will occur leading to higher H₂ generation. In this study, thermal stabilization of ferrite materials was also investigated by performing multiple thermochemical cycles using novel core-shell Ni-ferrite/ZrO₂/YSZ nanoparticles, which were synthesized using sol-gel and microemulsion routes. Using these materials grain growth mitigation as well as increase in H₂ volume generation was observed. Characterization of thermally stabilized ferrites and H₂ volume generated will be presented in detail.