The atmospheric pressure and temperature at about 50 to 60 km above the surface of Venus is nearly the same as that of the Earth, making its upper atmosphere the most Earth-like area in the Solar System. But it has thick sulfuric acid clouds and there's almost no water and no oxygen.
This Wikipedia article about the sulfur-iodine cycle gives this chemical equation:
2H$_2$SO$_4$ --> 2SO$_2$ + 2H$_2$O + O$_2$ (830$^0$ C)
Could concentrated sunlight be strong enough in the atmosphere of Venus to heat the sulfuric acid above 830$^0$ C ?
Or could a MMRTG deliver sufficient heat to create water and oxygen this way ?