Kindly refer to the following links:
Shall I say Alhamdulillah when I sneeze in Salah (Prayer) & Should others reply?
Saying Alhamdulillah during Salah
What to say when you Sneeze and how should others respond?
When I Sneeze should I say Alhamdulillah loudly so that other person can hear & reply
During prayer can we say Alhamdulillah if we sneeze or blow our nose with a tissue?