Many formal, pre-written prayers are for the morning or evening. Here is one I found for afternoons:

“God, as I go back into the busyness of my day, I offer all of my activities to you as an act of service. Please renew my energy while I work. Help me solve the problems I’m facing, and make good progress toward the goals I’m trying to achieve. Let your love flow through me into the lives of everyone I relate to for the rest of this day. Help me choose kind words and actions that encourage others and reveal your light shining through me toward them. Thank you for helping me with all I need for the rest of this day. Amen.”