Process for obtaining a mixed oxide comprising Ni, Mo, W, Al, optionally at least one metal Me and an organic component C or a residue derived from said organic component C by thermal decomposition or degradation during the calcination process, having the following formula, Mea Nib Moc Wd Ale Of pC wherein: - Me is selected from the group consisting of Zn, Cd, Mn, and a mixture thereof, - C comprises a polymer organic compound, - a is higher than or equal to 0, - b, c, d, e and f are higher than 0, and preferably are higher than 0.1, - f is equal to (2a+2b+6c+6d+3e)/2, - the (a+b)/(c+d) ratio is comprised between 0.9 and 1.1, - the a/b ratio is higher than or equal to 0 and lower than or equal to 1.5, - the c/d ratio is comprised between 0.2 and 5, - the (a+b+c+d)/e ratio is comprised between 0.6 and 5, and - p is the weight percentage of C, or possibly of the residue of C, with respect to the total weight of the mixed oxide of formula, and is higher than 0.2% and lower than or equal to 30%, calculated depending on the loss of weight analyzed by thermogravimetry and differential thermal analysis (TG-DTA) in the range of 150-600°C at a heating ramp of 10°C/min under an air flux of 200 cm 3 /min, said mixed oxide of formula comprising an amorphous phase and a pseudo-crystalline phase isostructural to Wolframite, wherein said process comprises the following steps: 1) mixing at least one soluble source of W and at least one soluble source of Mo into a suitable volume of water, until obtaining a clear aqueous solution; 2) optionally, adding at least one source of at least one element Me to the solution obtained in step 1; 3) adding at least one source of Ni to the mixture obtained in the previous step; 4) subjecting the mixture obtained in step 3 to a first heat treatment at temperatures comprised between 50° and 80°C, under stirring; 5) adding to the mixture obtained in step 4, at least one soluble, hydrolysable or dispersible source of Al, and at least one polymer organic compound comprising one or more heteroatom selected from 0 and N; 6) subjecting the mixture obtained in the previous step to a second heat treatment at temperatures comprised between 80°C and 95°C, under stirring, obtaining a suspension; 7) subjecting the suspension obtained in step 6 to drying, obtaining in such a way a solid phase; 8) calcining said solid phase obtained in the previous step, at temperatures equal or higher than 200°C and equal or lower than 450°C, in air or an inert atmosphere, for a time ranging from 3 to 20 hours, obtaining the mixed oxide of formula. - Me is selected from the group consisting of Zn, Cd, Mn, and a mixture thereof, - C comprises a polymer organic compound, - a is higher than or equal to 0, - b, c, d, e and f are higher than 0, and preferably are higher than 0.1, - f is equal to (2a+2b+6c+6d+3e)/2, - the (a+b)/(c+d) ratio is comprised between 0.9 and 1.1, - the a/b ratio is higher than or equal to 0 and lower than or equal to 1.5, - the c/d ratio is comprised between 0.2 and 5, - the (a+b+c+d)/e ratio is comprised between 0.6 and 5, and - p is the weight percentage of C, or possibly of the residue of C, with respect to the total weight of the mixed oxide of formula, and is higher than 0.2% and lower than or equal to 30%, calculated depending on the loss of weight analyzed by thermogravimetry and differential thermal analysis (TG-DTA) in the range of 150-600°C at a heating ramp of 10°C/min under an air flux of 200 cm 3 /min, said mixed oxide of formula comprising an amorphous phase and a pseudo-crystalline phase isostructural to Wolframite, 1) mixing at least one soluble source of W and at least one soluble source of Mo into a suitable volume of water, until obtaining a clear aqueous solution; 2) optionally, adding at least one source of at least one element Me to the solution obtained in step 1; 3) adding at least one source of Ni to the mixture obtained in the previous step; 4) subjecting the mixture obtained in step 3 to a first heat treatment at temperatures comprised between 50° and 80°C, under stirring; 5) adding to the mixture obtained in step 4, at least one soluble, hydrolysable or dispersible source of Al, and at least one polymer organic compound comprising one or more heteroatom selected from 0 and N; 6) subjecting the mixture obtained in the previous step to a second heat treatment at temperatures comprised between 80°C and 95°C, under stirring, obtaining a suspension; 7) subjecting the suspension obtained in step 6 to drying, obtaining in such a way a solid phase; 8) calcining said solid phase obtained in the previous step, at temperatures equal or higher than 200°C and equal or lower than 450°C, in air or an inert atmosphere, for a time ranging from 3 to 20 hours, obtaining the mixed oxide of formula.