Praise be to Allah.
Reciting Quraan in sujood is not allowed because of the hadeeth narrated by Ibn Abbaas (may Allaah be pleased with him) in which the Prophet (peace and blessings of Allaah be upon him) said: Indeed I have been told not to recite Quraan in rukoo and sujood.(Reported by Muslim, 738). But if some words from the Quraan are recited as duaa, such as (interpretation of the meaning): Our Lord! Give us in this world that which is good and in the Hereafter that which is good, and save us from the torment of the Fire! [al-Baqarah 2:201], then there is nothing wrong with this. As for reciting Sayyid al-istighfaar (the best form of seeking forgiveness) in sujood, there is nothing wrong with this, because this is counted as duaa. And Allaah knows best.