The resize2fs tool only works with ext2, ext3 and ext4 and it does not go with XFS filesystem.
Xfs_growfs is a similar tool which is compatible with XFS filesystems. So, you will have to install it first.
sudo yum install xfsprogs.x86_64 --assumeyes
After installing, mount your filesystem
sudo mount -t xfs /dev/sdf /vol
Now, using the xfs_growfs tool, you can expand your file system
sudo xfs_growfs /vol
df -h → this command should show the more available space