Praise be to Allah.
There is nothing wrong with the Muslim calling upon his Lord with names that match what he is asking for.
The Standing Committee said:
The one who is calling upon Allaah may seek to reach Him by means of any of His beautiful names by which He has called Himself or by which His Messenger (peace and blessings of Allaah be upon him) called Him. If he chooses names that suit what he is asking for, that is better. For example, he can say “Ya Mugheeth aghithni (O Reliever, help me), Yaa Rahmaan irhamni (O Most Merciful, have mercy on me), Rabb ighfir li wa arhamni innaka anta al-Tawwaab al-Raheem (O Lord, forgive me and have mercy on me, for You are the One Who accepts repentance, the Most Merciful).”
Fataawa al-Lajnah al-Daa’imah, 1/91.
But making up a du’aa’ to be said after prayer is a kind of innovation or bid’ah. See Questions nos. 32443 and 10491.
Moreover, it is better to make du’aa’ in the prayer itself, when prostrating and before saying the tasleem. With regard to making du’aa’ after the tasleem, it is not proven that the Prophet (peace and blessings of Allaah be upon him) did this.
With regard to reciting the verse (interpretation of the meaning):
“And (all) the Most Beautiful Names belong to Allaah, so call on Him by them, and leave the company of those who belie or deny (or utter impious speech against) His Names. They will be requited for what they used to do”
– or reciting the last verses of Soorat al-Baqarah after prayer, there is no evidence for that in the Sunnah. Rather it was narrated that the Prophet (peace and blessings of Allaah be upon him) used to recite the last two verses of Soorat al-Baqarah every night.
The Prophet (peace and blessings of Allaah be upon him) said: “Whoever recites the last two verses of Soorat al-Baqarah at night, that will suffice him.”
Narrated by al-Bukhaari, 4008; Muslim, 807
It was said that what this means is that it will be sufficient for him so he does not need to pray qiyaam al-layl, or that they will suffice to protect him from the Shaytaan, or from all evil.
Al-Shawkaani said: There is no reason why it should not mean all these things… for the bounty of Allaah is immense.
Al-Haafiz said: It may be that it means all of the above.
Al-Nawawi said: It may be that all are meant.
And Allaah knows best.