Are there supererogatory prayers before and after the dhuhr prayer?

The Prophet (peace and blessings be upon him and his family) said: "The angels will build a house in paradise for whoever performs twelve voluntary rak'as [cycle of prayer] per day."
These are as follows:
- Two rak'as before the fajr [dawn] prayer.
- Four rak'as before the dhuhr [noon] prayer and two after it.
- Two rak'as after the maghrib [sunset] prayer.
- Two rak'as after the 'isha [night] prayer.
Whoever performs these prayers on a regular basis will obtain this reward.
As for the Sunnah prayer performed before 'asr [midafternoon] prayer, the Prophet (peace and blessings be upon him) said: "God bestows His mercy on whoever performs four voluntary rak'as before the 'asr prayer." In another narration, the Prophet (peace and blessings be upon him) said that the Sunnah prayer for 'asr comprises of two rak'as. He (peace and blessings be upon him) said: "The angels will build a house in paradise for whoever performs twelve voluntary rak'as per day. These are: four rak'as before the dhuhr prayer and two rak'as after it, two rak'as before the 'asr prayer, two rak'as after the maghrib prayer and two rak'as before the fajr prayer" [recorded by Al-Hakim in his Mustadrak].
And God the Almighty knows best.