For increase focus in study, the best dua for studying is surah Taha Ayat 25 to 28.

قَالَ رَبِّ اشْرَحْ لِي صَدْرِي – وَيَسِّرْ لِي أَمْرِي – وَاحْلُلْ عُقْدَةً مِّن لِّسَانِي – يَفْقَهُوا قَوْلِي

You can recite this dua after Faraz Namaz 101 times is going to increase your focus with your study. Moreover, before start study, you can do wadzu and recite the same dua 33 times.

Furthermore, you can decrease things that are preventing you to focus. For example, use a lot of mobile, social media, and friends gathering.

Also, you can eat Harad Murabba every day for breakfast. If you are from a third-world country and you find Murabba in the market is unhealthy. So better if you make it at home. Harad is too much give benefits to boost your focus.

Akhtar Bhai I make this dua for concentration in study and memory?