TAILORING NOVEL MATERIALS FOR GLOBAL CO_2 RECYCLING

我们建议建立一个CO_2回收系统，以防止CO_2排放与人类活动的发展相结合造成的全球变暖。该系统包括CO_2的甲烷化，CO_2在燃料消耗场所（如发电厂）回收。甲烷化需要高活性的催化剂和氢气，而氢气可以利用太阳能电解海水获得。为了实现这一系统的全球规模，我们需要开发低成本的催化剂和电极，在海水电解析氢和析氧反应的效率高。本研究的目的是开发这种新型的甲烷化催化剂和电极材料，我们发现由非晶态Ni-Zr合金制备的甲烷化催化剂具有很高的甲烷化活性。我们还成功地开发了以非晶态Ni-Zr-Sm合金为前驱体的活性更高的催化剂。结果表明，钐稳定了氧化锆的四方相，Ni颗粒在四方相上分散， ...更多信息 文章也得到了加强。采用气体雾化法制备的Ni-Zr-Sm合金电极也具有较高的析氢活性，采用电沉积法制备的Ni-Mo和Co-Al-Mo合金电极具有较高的析氢活性。采用电弧离子镀方法，不仅提高了Ni-Mo合金电极对基体的附着力，而且提高了电极的析氢效率;当电流密度为4×10^3A/m^2时，析氢过电位小于100 mV，最佳组成为Ni-（10-20）at%Mo-（5-10）at%O。钛基MnO_2型氧化物电极电解海水的析氧效率。所制备的电极结构为化学均匀的纳米晶锰氧化物，具有γ-MnO_2结构，其中固溶有六价钨。实验还发现，钼和钨的组合添加是更有效的选择性析氧在海水电解，我们能够成功地降低电解电压。少

We are proposing a CO_2 recycling system for preventing global warming caused by CO_2 emissions in conjunctions with development of human activities. The system contsists of methanation of CO_2 which are recovered at fuel consumers sites such as power plants. Methanation needs highly active catalysts and hydrogen which can be obtained from seawater electrolysis using solar energy. To substantiate this system global scale, we need to develop low cost catalysts and electrode with high efficiency for hydrogen evolution and oxygen evolution reactions at seawater electrolysis. The objectives of this investigation are to develop such new catalysts and electrode substances.We have found methanation catalysts prepared from amorphous Ni-Zr alloys have high activity for methanation. We have also succeeded in develop more active catalyst using amorphous Ni-Zr-Sm alloys as precursors of the catalysts. It was clarified that samarium stabilize tetragonal phase of zirconia on which dispersion of Ni p … More articles are also enhanced. Catalysts prepared from gas-atomized Ni-Zr-Sm alloys also had high activity.Ni-Mo and Co-Al-Mo alloy electrode fabricated by sputter-deposition showed high activity for hydrogen evolution reaction. By using arc-ion-plating method, not only adhesiveness to the substrate but also hydrogen evolution efficiency of Ni-Mo alloy electrode was improved ; the most effective composition was Ni-(10-20)at%Mo-(5-10)at%O with the overpotential for hydrogen evolution lower than 100 mV at the cuurent density of 4×10^3A/m^2.It was succeeded to prepare an electrode with 100% oxygen evolution efficiency for seawater electrolysis using MnO_2 type oxide electrode installed on titanium stubstrate. The structure of the prepared electrode consisted of chemically homogeneous nanocrystalline manganese oxide with γ-MnO_2 structure containing solid-solved hexavalent tungsten. It was also found combined addition of Mo and W is more effective for selective oxygen evolution at seawater electrolysis and we were able to reduce electrolysis voltage successfully. Less