Hydrogen Production via Hydrolysis of Zn in a Hot Wall Flow Reactor

Hydrolysis of Zn is investigated as the second step in a ZnO/Zn redox solar water splitting process. Zinc is evaporated and hydrolyzed in a hot wall flow tubular reactor. The design of the reactor was suggested by prior studies at ETH-Swiss Federal Institute in which simultaneous synthesis of hydrogen and zinc oxide nanoparticles was the goal. The influence of the reactor temperature and residence time on hydrogen conversion was measured for 1023 and 1073 K. Particle yield was measured in-situ using a scanning differential mobility sizer. Particle composition and morphology were characterized with X-ray diffraction and microscopy. In agreement with the prior work, hydrogen conversions of 87 to 96 percent at temperatures above zinc saturation are attributed primarily to hydrolysis of zinc(g) at the wall of the reactor.