(598b) Rational Design of CeO2-Based Catalysts for Enhanced Water-Gas Shift Reaction

Water-gas shift reaction (WGSR) is important for chemical processes that use hydrogen resources. It has been widely used in fertilizer and petroleum refining industry. Nowadays, the WGS reaction is also aimed at preventing carbon monoxide (CO) poisoning which deactivates fuel cells. In the hydrogen flow supplied to the fuel cell, CO is contained, which is adsorbed on the anode to cause inactivation. Therefore, before the hydrogen is supplied to the anode, the WGS reaction process is performed to oxidize the contained CO to prevent poisoning. Supported metal catalysts are mainly used for the WGS reaction, and the support reducibility of these catalysts is widely known as an important factor that affects the activity. WGS reaction is catalyzed by redox and associative mechanisms, so the reducibility of catalyst plays an important role in the activity. Controlling the support reducibility can form a large amount of oxygen vacancies (O_v) on the catalyst surface. These O_v increase the lattice oxygen mobility, and help oxygen more easily participate in the oxidation reaction. Therefore, many studies to improve the support reducibility are actively underway. In this study, we prepared supported metal catalysts that controlled the reducibility of CeO₂ by metal-doping and morphology modification. First, we identified whether the catalyst structure was well formed from each approach. Subsequently, the synthesized catalyst was confirmed to have higher activity than un-modified catalysts and a reducibility test was conducted to prove that it was related to reducibility. Furthermore, we designed the catalyst using two strategies simultaneously to improve the reducibility described above.