A method for purifying a sulfur-containing fuel oil comprising (a) contacting the fuel oil with a supported exogenous binary catalyst and oxygen at a temperature in a range of from about 25° C. to about 150° C., and at a pressure in a range of from about 1 atmosphere to about 150 atmospheres to provide a first oxidized mixture; and (b) separating at least one oxidized sulfur compound from the first oxidized mixture to a provide a purified fuel oil. In one embodiment, the sulfur-containing fuel oil is deasphalted prior to contacting with the supported exogenous binary catalyst and oxygen.