Filtro eletroquímico para remoção de monóxido de carbono de gás de reforma

Abstract

Alternative energy power are the subject of intensive research concerning the replacement of traditional fossil fuels. Hydrogen from reforming of biofuels for use in fuel cell systems (FC) is amongst the most promising candidate as a clean and renewable source. However, the gas from the reform process comprises harmful compounds to the efficient FC operation, mainly carbon monoxide, which strongly poisons the electrocatalysts used in the FC. The present work aims to develop a filter based on electrochemical processes (EF) for the removal of CO from the reformate gas. Electrochemical experiments were conducted to evaluate the performance of ruthenium nanoparticles as the electrocatalyst in the EF anode, on the basis of their selectivity towards the electrooxidation of CO over the H2 electrooxidation. The catalysts used in this study consisted of Ru NP dispersed on high surface area carbon (Ru/C) and sintered porous titanium (Ru/Ti) substrates. The Ru/C electrocatalysts were found to be very active towards the H2 electrooxidation in the whole potential range, and no inhibition at high potentials were observed as in the typical case of bulk Ru. This renders the Ru/C catalysts little selective towards CO oxidation. The Ru/Ti electrocatalysts also displayed high catalytic activity towards H2 electrooxidation, however, the inhibition at high potentials were CO is oxidized was observed in this case. Nevertheless, the combined inhibitory effects of the Ru oxide formation and the CO adsorption was not enough to enhance the selectivity of the electrocatalyst so it can be efficiently used in the EF. Indeed, the Ru NP electrocatalyst showed a remarkable CO tolerance in its activity towards H2 electrooxidation, hindering it from being used in CO filter applications, but making it eligible for applications where CO tolerance is a desired feature.