Carbon monoxide and carbonyl sulfide emissions are reduced in manufacturing processes, including titanium tetrachloride production processes. Gas is contacted with CO, COS, and an oxygen-containing gas with a suitable catalyst. The catalyst may be a metal oxide catalyst containing bismuth, cobalt and nickel, a xerogel or aerogel catalyst containing Au, Rh, Ru and Co in aluminum oxide/oxyhydroxide matrices, or a supported metal catalyst that contains at least one metal from the group Pd, Rh, Ru and Cu. In the latter case, the catalyst support is contains alumina or carbon. A catalyst composite of Au, Rh, Ru and Cr, and cerium oxide and lanthanum oxide may also be used.