Harnessing the Beneficial Attributes of Ceria and Titania in a Mixed-Oxide Support for Nickel-Catalyzed Photothermal CO_2 Methanation

Solar-powered carbon dioxide （CO_2）-to-fuel conversion presents itself as an ideal solution for both CO_2 mit- igation and the rapidly growing world energy demand. In this work, the heating effect of light irradiation onto a bed of supported nickel （Ni） catalyst was utilized to facilitate CO_2 conversion. Ceria （CeO_2）-titania （TiO_2） oxide supports of different compositions were employed and their effects on photothermal CO_2 conver- sion examined, Two factors are shown to be crucial for instigating photothermal CO_2 methanation activity： ① Fine nickel deposits are required for both higher active catalyst area and greater light absorption capacity for the initial heating of the catalyst bed; and ② the presence of defect sites on the support are necessary to promote adsorption of C02 for its subsequent activation, Titania inclusion within the support plays a crucial role in maintaining the oxygen vacancy defect sites on the （titanium-doped） cerium oxide. The combination of elevated light absorption and stabilized reduced states for CO_2 adsorption subsequently invokes effective Dhotothermal CO_2 methanation when the ceria and titania are blended in the ideal ratio（s）.

太阳能驱动二氧化碳(CO_2)转化为燃料是解决CO_2减排和快速增长的世界能源需求的理想方案。本文利用光照辐射镍基负载催化剂床层引发加热效应以促进CO_2的转化,研究了不同组成的氧化铈-氧化钛复合氧化物载体及其对光热CO_2转化的影响。提高光热CO_2甲烷化活性的两个至关重要的因素分别是:(1)优化的镍颗粒负载对于高活性催化面积及用于加热催化床层的更高的光吸收能力是必需的;(2)载体上的缺陷位对于促进CO_2吸附及随后的活化是必需的。载体中的钛对维持掺杂氧化钛的氧化铈上的氧空位缺陷起着关键作用。当氧化铈和氧化钛混合比例理想时,再结合高光照吸收以及稳定的还原状态,有利于CO_2吸附及随后高效光热CO_2甲烷化反应的发生。