Unfortunately, it is not possible to freeze and split panes at the same time in Microsoft Excel. When you freeze panes, it will freeze all rows above and columns to the left of the selection, and the split bar will be removed.

However, there is a workaround that you can use to achieve a similar effect. You can split the panes first, and then freeze the top row or left column. This will allow you to keep the split panes while also freezing a specific row or column.

Here are the steps to split and freeze panes in Excel:

1. Select the cell in the worksheet where you want to split the panes.
2. Go to the "View" tab in the ribbon.
3. Click on the "Split" button in the "Window" group.
4. Drag the split bar to the location where you want to split the panes.
5. Once you have split the panes, select the cell in the top row or left column that you want to freeze.
6. Go to the "View" tab in the ribbon.
7. Click on the "Freeze Panes" button in the "Window" group.
8. Select "Freeze Top Row" or "Freeze First Column" from the drop-down menu.

Now you should have a split pane with a frozen row or column. You can adjust the split bar and freeze panes as needed to customize your view.