Range hoods should be vented using metal ductwork. Smooth ducting is better than flexible or ribbed. This is because smooth straight ducting won't diminish or restrict the airflow as much as flexible ductwork will. That also needs to be taken into consideration when thinking or planning to add elbows to your ductwork.
Don't ever use 4 inches dryer duct or any plastic ducting on a range hood installation. The minimum size duct allowed on most range hoods is 3 ¼ inches by 10 inches which is equivalent to 6 inches round. More powerful hoods require even larger duct sizes up to 10 inches round. When remodeling, changing hoods, or cooking equipment, do not reduce the ductwork size to less than the size specified for the range hood. Decreasing the duct size restricts the performance and decreases the unit's longevity.