1. I'm determined to study harder
2. I determine to study harder.
Are there any differences between 1 and 2?
Yes there is difference between the both.
The first sentence is showing your ambition, while the second one is showing your decision.
When I failed my first set of exams, I determined to try harder at the next set.
I should add that we would be more likely to say "I decided to" or "I resolved to" in that example. Alternatively, we would say "After failing my first set of exams, I was determined to do better in the next set".
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.