Your donation will be split amongst maintaining the mosque, teaching the Qur’an and sacred knowledge, and instilling piety. All of these are the type of deeds that are considered ongoing charity. Your reward will go on for generations, in sha Allah.
“By no means shall you attain piety, unless you spend (in Allah’s Cause) of that which you love; and whatever of good you spend, Allah knows it well.” — Al-Imran 3:32