There are studies that show that it is not necessary to clean the umbilical cord with any "disinfectant" solution. The way that parents are taught to clean the umbilical cord differs from hospital to hospital.
If parents are taught to use any disinfectant, alcohol is usually preferred. You should clean your baby's umbilical cord according to the instructions of the hospital in which the baby was born, or according to your pediatrician who will be evaluating your baby's health.