a process for selectively converting h 2 s to s , utilizing a porous catalyst having the atomic proportions covered by the formula fe a zn b , wherein a has a value of 0 . 5 to 10 and b has a value of 1 to 2 . the catalyst contains substantially no chromium . a gas stream comprising hydrogen sulfide and oxygen is passed over the catalyst at a temperature above the dew point of sulfur and up to about 300 ° c .