Development of Reactive Ceramic Devices for High-Temperature Solar Thermo Water Splitting

在本研究项目中，我们开发了用于太阳能热化学两步分水循环的反应陶瓷器件，以利用太阳带地区的高温太阳能。主要研究结果如下：1.高活性陶瓷粉末的研制我们研究了其他金属掺杂对氧化锆负载铁氧体的影响，发现Ni_(0.1)&gt；Fe_(？)lt；2.0&gt；O_4/ZrO_2是活性最强的粉末。另一方面，我们还发现，当Y3-立方稳定的氧化锆或YSZ代替普通的单斜氧化锆作载体时，YSZ与担载在YSZ上的FeBBB；3B；OB&lt；4B&gT；在1400℃的惰性气氛中发生高温反应生成含铁的YSZ或Fe^&lt；2+P&gT；-YSZ，然后FePPP^&lt；2+P&gT；-YSZ在1000-1100℃下与水蒸气反应生成氢。-在惰性大气中，在1400℃以上的温度下，通过单独的热还原步骤重新激活的YSZ。反应装置的制备及反应性测试制备了包覆了Ni1.0&gt；Fe2.0&gt；O4/ZrO2或Fe3O4/YSZ颗粒的泡沫氧化锆作为反应装置，并在1100~1400℃之间交替进行了两步水分解循环的反应活性测试。在重复13-30次循环中，成功地继续产生氢气，但泡沫装置在重复循环后出现裂纹和断裂。反应装置的基质应选用抗热震性较高的泡沫陶瓷，如泡沫碳化硅。泡沫碳化硅涂层及耐太阳辐射性能测试在将FeBB_&lt；3BB&gt；OBB_&lt；4BB&gt；另一方面，利用太阳炉测试了碳化硅泡沫基质在太阳辐射下的耐热性，结果表明，碳化硅泡沫基质具有良好的耐热性。

In this research project, we have developed reactive ceramic devices to be used in solar thermochemical two-step water splitting cycle, for utilizing high-temperature solar heat in sun-belt regions. The main results are listed below :1. Development of High Reactive Ceramic PowdersWe investigated the other-metal doping effect on the ferrite supported on zirconia and found that Ni_<0.1>Fe_<2.0>O_4/ZrO_2 is the most reactive powder. On the other hand, we also found that, when yttrium-cubic-stabilized zircionia or YSZ is used as support instead of normal monoclinic zirconia, an iron-containing YSZ or Fe^<2+>-YSZ is formed by a high-temperature reaction between YSZ, and FeBBB_<3B>OB_<4B> supported on the YSZ at 1400℃ in an inert atmosphere, and that the FePPP^<2+P>-YSZ then reacts with steam and generate hydrogen at 1000-1100℃, to form FeP^<3+P>-YSZ that is re-activated by a thermal reduction in a separate step at temperatures above 1400℃ under an inert atmosphere.2. Preparation and Reactivity Test of Reactive DevicesZirconia foams coated with the Ni<1.0>Fe_<2.0>O4/ZrO_2or Fe_3O_4/YSZ particles were prepared as reactive devices and examined on reactivity for two-step water splitting cycle being performed alternately at temperatures between 1100 and 1400℃. Hydrogen successfully continued to be produced in the repeated 13-30 cycles, but foam device had cracks and broken after the repeated cycles. Ceramic foams with a higher thermal shock resistance, such as SiC foam, should be used as the matrix of the reactive devices.3. Coating of SiC foam with Ziconia and Performance test for Thermal Resistance under Solar IrradiationThe SiC foam matrix was successfully coated with zirconia layers before FeBB_<3BB>OBB_<4BB> is applied on the matrix. On the other hand, the SiC foam matrix was examined on thermal resistance under solar irradiation using solar furnace and, as the results, we found that the SiC foam matrix has a good thermal resistance.