Sunan Abi Dawud Book 2, Hadith 391
The Messenger of Allah (ﷺ) kept silence between the takbir and the recitation of Qur’an. So I asked him, for whom I would give my father and mother as ransom: What do you say during you period of silence between the takbir and the recitation? He replied (that he said): O Allah, purify me from sins as a white garment is purified from filth. O Allah, wash away my sings with snow, water and hail.
I remember from the Messenger of Allah (ﷺ) two periods of silence. Sa'id said: We asked Qatadah: What are those two periods of silence? He said: (one) when he began his prayer, and (one) when he finished the recitation. Then he added: When he finished reciting (the closing verse of the Fatihah): "Not of those with whom Thou art angry, nor of who go astray."
The Prophet(peace be upon hm), Abu Bakr, ‘Umar and ‘Uthman used to begin the recitation with “Praise be to Allah, the Lord of the Universe.”