Hydrogen purification apparatus and method and fuel cell power generation system and method

A hydrogen generator comprising:

• a reformed gas inlet for introducing a stream of reformed gas, the reformed gas comprising hydrogen, carbon monoxide, and steam;
• a shifting unit for reducing the concentration of carbon monoxide in the reformed gas, the shifting unit comprising a carbon monoxide catalyst body for removing carbon monoxide with a shifting reaction, and
• a reformed gas outlet for discharging the reformed gas from said shifting unit:
• wherein:
• said carbon monoxide shifting catalyst body comprises at least one noble metal selected from the group consisting of Pt, Pd, Rh and Ru;
• said noble metal is supported on a carrier comprising a complex oxide of Zr compounded with at least one element selected from the group consisting of Mo, W, and Re;
• the atomic ratio of the total amount of Mo, W, and Re to the total amount of Mo, W, Re, and Zr in the complex oxide is 0.01 to 0.90;
• and
• said complex oxide is a solid solution.