Is that really that much of an issue though? Combustion engine cars are for sure emitting CO2, electric cars might emit CO2 depending on where you got your electricity from on any given day. What's actually the efficiency of an electric car these days? Combustion engines aren't that efficient so it might actually not matter per carbon atom anyway.
Yeah platinum is still the most viable catalyst for the oxygen reduction reaction in a fuel cell. It's not perfect but better than anything else we've tried so far. It's not that you need large amounts of it per car, it's just that we'd need, as far as I remember, about 50 years worth of platinum to convert e.g. the entire American car fleet to fuel cell cars so it's not really viable on the large scale at present (which raises the question of whether everyone should expect to have a car). I'm sure there's a place for hydrogen as an energy carrier in the future, because frankly we need everything we can get.
In some way more electric cars could be imagined to alleviate this as you'd just use them as storage to some degree in a smart grid.
But we probably can't get around developing good electrocatalysts though.
