Abstract: The desulfurization of gaseous effluents containing contaminating amounts of objectionable sulfur compounds, typically via the Claus reaction and notably in the presence of oxygen, utilizing a support substrate, e.g., titanium dioxide, having an active catalytic phase deposited thereon, such active catalytic phase being constituted of an electroneutral solid solution having the average composition:A.sub.4.+-.y V.sub.2.+-.x O.sub.9in which A is a metal other than vanadium, e.g., magnesium, calcium or zinc, 0.ltoreq.x.ltoreq.0.2 and 0.ltoreq.y.ltoreq.0.5.