Do you think teaching professionally is quite enough to motivate students to study?

I think for better motivation you should have better teaching atmosphere to enhance interest in students for better learning. As well as you must have psychological skills to enhance interest in students for learning. But a good Teacher is also a good motivator.

Teaching is exactly using your artful teaching ways to make learning much more motivating and interesting. I even consider that teaching resembles to a" show" you adore performing and rehearsing to captivate the students' attention....Therefore professionalism in knowledge integrated with skillful and motivating teaching create teaching creativity ....

No.To encourage students to become self-motivated independent learners, instructors can do the following:

• Give frequent, early, positive feedback that supports students' beliefs that they can do well.
• Ensure opportunities for students' success by assigning tasks that are neither too easy nor too difficult.
• Help students find personal meaning and value in the material.
• Create an atmosphere that is open and positive.
• Help students feel that they are valued members of a learning community.

theory and Practice are different things. the ideal is that you use the theory on your practice as teacher, it will help a lot. 

But motivation you have2 ways: extrinsically and intrinsically. As professor your responsibility is to improve this extrinsically motivation on your students, a good way is the Human centered design on your courses and activities. 

the intrinsically is the hardest one, because there is involved psychological facts that not all the teacher can handle, not because he is not prepared, because that is not his field, for that i advice that talk with a counsellor or the school therapist.

Teaching is an art that  glow up by perpetual  practice, use of  professional knowledge and realizing own strong points. Motivation is a catalyst that augments the process of learning between the teacher and learners. 

No but in other to motivate a student to study mostly as a professional you need to encourage the without the program that they chose is their career profession. You must advice with which materials can it help them to pass their exam. You must always set examples and let them no their remodel.