A method for modification of pretreated acidic porous material via selective cation exchange using suitable solvent to obtain higher noble metal dispersion is described herein. The solvent system required for cation exchange should have its dielectric constant in the range of 25-45, wherein this solvent property is found to impart significant effect on cation loading and distribution, which in turn defines the stability, dispersion of the noble metals. The catalyst so obtained has higher noble metal dispersion and when used for hydroisomerization reaction, leads to higher selectivity even at significantly high conversion values.