Catalyst compromising a mixed sulphide and its use for hydrorefining and hydroconverting hydrocarbons

A catalyst comprising a porous matrix and a mixed sulphide comprising at least two metals selected from the group consisting of metals having the following atomic numbers:

• 3, 11, 12, 19 to 33, 37 to 51, 55 to 83, 87 to 103, characterized in that said mixed sulphide results from a combination of at least one metal the sulphide of which has a bond energy between the metal and sulphur of less than 50.+-.3 kcal/mol (209.+-.12 kJ/mol) and at least one metal the sulphide of which has a bond energy between the metal and sulphur of more than 50.+-.3 kcal/mol (209.+-.12 kJ/mol), said mixed sulphide thus having a mean bond energy between the metal and sulphur which is in the range 30 to 70 kcal/mol.(125 to 293 kJ/mol) with the proviso that said metals are present in catalytic proportions which yield synergistically high hydrodesulfurization activities, and with the proviso that said mixed sulphide does not comprise any of a combination of sulphur and molybdenum-nickel and a combination of sulphur and molybdenum-cobalt.