Assalumalaikum warahmatullahi wabarakatuhu Sheikh. Is there any dua to be recited before Takbiratul Ihram in any kind of salah, like fard, sunnah or nafl? My family members usually recite this dua before takbeer and then say the takbeer:- "I have turned my face in complete devotion to the One Who created the heavens and the earth, and I am not one of the polytheists". Is this an innovation?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

No supplication is obligatory before the opening Takbeer. The well-known opening supplication (Al-Istiftaah supplication) is to be recited right after the opening Takbeer, not before it, according to the Majority of scholars, but it was reported that some scholars said that it can be recited before the opening Takbeer.

Ibn Habeeb  said: It is to be recited after Iqaamah and before the opening Takbeer. He said in Al-Bayan (which is one of the trustworthy books): It is good.

Accordingly, reciting the opening supplication before the opening Takbeer is not considered an innovation, but it is better and more appropriate to follow the Sunnah and what was acted upon by the majority of Scholars, and that is to be recited after the opening Takbeer.

Allah knows best.