Is it recommended to recite specific surahs from the Holy Quran in supererogatory prayers?

No specific recitation has been prescribed for supererogatory prayers (nawafil), except for the two rak'ahs of Fajr and Maghrib, in which Surat Al-Kafirun and Surat Al-Ikhlas are recited. As for Witr and Shafa', in the Shafa' (even rak'ahs), Surat Al-A'la and Al-Kafirun are recited, and in Witr (odd rak'ah), Al-Ikhlas and the two Mu'awwidhatayn (Surat Al-Falaq and Surat An-Nas) are recited.