...and a bit more info"Currently, Daihatsu uses about 100 grams...

...and a bit more info

"Currently, Daihatsu uses about 100 grams of platinum per vehicle in its hydrogen-based fuel-cell vehicles under development. Ordinary gasoline vehicles use about 5 gram per vehicle of platinum as a catalyst to filter out carbon monoxide and particulate emissions."

Lots of work being done to eliminate the need for platinum, but looks much further from being a commercial reality than the proven platinum cells.