This invention relates to a fuel reforming apparatus for producing a carbon-monoxide free reformed fuel gas comprising hydrogen. More particularly, this invention relates to nonthermal plasma reactors for removing carbon monoxide from a reformed fuel gas produced from a fuel containing bonded atoms of hydrogen exiting a reformer. More particularly, this invention relates to nonthermal plasma reactors for reforming a fuel containing bonded atoms of hydrogen into a reformed fuel gas. This invention relates further to hydrogen-oxygen fuel cells, which comprise a fuel reformer for reforming a fuel into a reformed fuel gas comprising hydrogen, a carbon monoxide remover for removing carbon monoxide in the reformed fuel gas and supplying the reformed fuel gas to the fuel cell.