Prius 3rd Gen throws P0420, is it a bad Oxygen sensor?

I recently purchased a 2013 Prius with 114000 miles on it. The engine light is ON and I scanned for the code and got P0420 "Catalyst System Efficiency below Threshold bank1". I have gone through our previous threads on similar issues and ended up with culprit Oxygen sensors. I checked the voltages from O2 sensors and O2B1S2(V) = 0.788 and O2B1S1(V) = 3.401 at RPM 2500.

From our forum, on third-gen Prius, the O2B1S1 is actually an Air Fuel Ratio Sensor (Located backside of the engine, before the catalytic converter, where we need to remove the whole wiper assembly to access it). What is the normal voltage range from this sensor? Some threads it says between 0.6 to 1 V. Some threads it says 3 to 3.8 V. Which one is correct?. Is this an O2 sensor or a AF ratio sensor? Does this sensor cause P0420?

O2B1S2 sensor, I believe located after the catalytic converter, which we can access easily from the bottom of the car. What should be the normal range of voltage expected from this sensor? Does this cause P0420?

Also, could anybody share the normal range of values for OBD II Live Data?

Thanks in advance
Melvin