Reference : Hisn al-Muslim 73

اللَّهُمَّ إِنِّي أَسْأَلُكَ عِلْماً نافِعاً
وَرِزْقاً طَيِّباً وَعَمَلاً مُتَقَبَّلاً
(بَعْدَ السّلامِ مِنْ صَلاَةِ الفَجْرِ) 
Allāhumma innī as'aluka `ilman nāfi`an, 
wa rizqan ṭayyiban, wa `amalam-mutaqabbala.

[to be said after giving salam for the Fajr prayer.]

"O Allah, I ask You for knowledge which is beneficial, 
and sustenance which is good, and deeds which are acceptable."


Reference:
Ibn Majah and others. See Sahih Ibn Majah 1/152 and Majma' Az-Zawa'id 10/111

Chapter: After salam