According to our previous work [10], the copper–cerium oxide catalytic system is a very promising one for efficient CO removal from a hydrogen-rich gas using microreactor technology. The selectivity of the copper–cerium oxide catalyst is considerably higher ascompared to that of Pt metal supported catalysts at a similar level of CO conversion. The stability is also considerably higher [17,18] as compared to Au-containing catalysts. The latter may rapidly decrease their activity under reaction conditions. Furthermore, theprice of the copper–cerium oxide catalyst may favorably compete with platinum containing catalysts.