Pheromone spray?

My male cat, Loki has been marking by my front door and under my son's crib. He is fixed btw! I have used vinager and laundry detergent to clean it which doesn't get all the smell out along with baking soda. I have also tried lemon juice to deter him from doing it again. Btw, the lemon juice hasn't worked. Anyway, I have heard that pet stores sell a pheromone spray that will stop the marking. Something about not peeing in "happy spots" LOL. Any help about cat marking would be appreciated. Thanks!