And on a space station, most of your heat differential is created by active cooling, so recovering that via Peltier elements is a bit… counter productive.
It's actually the complete opposite - space is not "infinitely cold" it's more like "infinitely isolating" - like the perfect giant thermos. Space suits for example have a whole layer of water tubes just to cool down the astronaught, otherwise they will pass out from their own body's temperature.
Some of it probably could be, but the effiency of those processes are low enough that you'd still have a heat problem. Also, recall that the energy originated with the solar panels to start with. It's a very wasteful way of generating electricity compared to the solar panels, so although it might be worth considering to recover some of the energy investment and eliminate a fraction of the heat, the net output of such a process will probably be an order of magnitude lower than the initial energy investment.
Only a difference in heat levels can still be converted to electricity, for instance by reverse Peltier effect: https://en.wikipedia.org/wiki/Thermoelectric_cooling