Ignoramus3825 fired this volley in
:

Yes, but they kept TiO2...

Again, Ig, you should call those "the catalyst pellets", and not "TiO2".

They _may_ have a titanium dioxide SUBSTRATE (usually it's alumina [Al2O3],
shrug), but that's not the catalyst.

As Bob correctly said, sintered oxide pellet is nothing but an INERT solid
that can withstand high temperatures. Usually a rather thin layer of a
catalytic metal is vapor-deposited on the outsides of the pellets.

Lloyd