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A screening of new base metal oxides, which suppress H2S formation in Pt/Rh/CeO2 TWC catalysts, has been conducted using thermodynamic calculations. As a result, several promissing candidates were found, and most of the candidates exhibited H2S suppression effects in an engine H2S formation test. However, many of these candidates for Pt/Rh/CeO2 TWC catalyst negatively affected catalytic performance after thermal and engine agings. Among the candidates, the most prospective candidate as a non-Ni type H2S scavenger was GeO2. Test results of an advanced type Pt/Rh/CeO2 TWC catalyst with GeO2 also showed both H2S suppression effectiveness and no negative effects on catalytic performance. This catalyst is expected to be one of non-Ni low H2S Pt/Rh/CeO2 TWC catalyst candidates for near future applications.