I've always thought that the use of the preposition 'to' with the verb 'convince' is correct. But I recently learned from a reliable source that 'to' shouldn't be used with 'convince' but rather with 'persuade'. So instead of saying for instance 'I should try to convince him to work harder', I'd rather say 'I should try to convince him of his ability to work harder' or 'I should try to convince him that he can work harder' or 'I should persuade him to work harder.'

Honestly, I'm still perplexed. Could anyone shed some light?