resize2fs works on the formatted filesystems(mke2fs), generally created over the logically created partitions(lvcreate).
If vg0 (volume group) has 23g free space, then why do you need resize2fs? You can perhaps create another logical volume from the volume group, formate the new logical volume and mount it.
If you need more room out of your existing volume group, then you need not do
pvresize at all. Just start with resizing the filesystem that has enough free space and can sustain giving out the needed disk space. To shrink the volume, You can directly do a reduction of filesystem size with
resize2fs but better do it on an umounted filesystem. Now
lvreduce can reduce the volume to make more space for to be newly created logical volume and a filesystem.
If you need more room into your existing volume group, and you are probably adding more physical volumes or disks, then you need
pvresize followed by
lvextend and then
Better start the approach by taking the notes from
lvdisplay and then muck around. If anything goes wrong, you will be sure what was the state earlier.