If you need a cert to keep your current position and it wasn’t required when you started, that’s one thing.

If you need a cert to promote and climb within the company that’s totally different. That’s education and qualifications that you need if you choose to climb the ladder and make more. There isn’t really any reason the company should have to pay you for this time for you to study and obtain those certifications. If you decide you want more money, then you will decide to study outside of work. If you wanted a position that required a bachelor’s degree at your company, would you expect the company to pay for your degree and pay for your time at college?