Is the aforementioned supplication sound or not?

A Muslim should observe the etiquettes of supplication (du'a), such as humility and certainty of response. He should supplicate with whatever prayers are easy for him, provided they conform to Islamic rulings, even if they are not transmitted (ma'thur). The supplication mentioned does not violate Islamic law, though it is better to supplicate with what is transmitted from the Qur'an and Sunnah.