ssgi4in12

My 2002 Rx 300 throws a P0420 cel after about 3 weeks I got it. To ascertain what the culprit is really, I had to buy a scan tool, Torgue. I used the scan tool to read the voltage of the 2 a/f sensors. It shows as 02 sensor bank 1 sensor 1 wide range
and 02 sensor 5 wide range. When car ignition is in on position, the voltage of the two sensors are 3.3v but when car is started, the voltage can change to 3.28, 3.31 and it never gets below 3.1v. That is for the two wide range sensors.

Then I had to look at the bank 1 sensor 2, when the car is started and its in idle, the sensors reads out at 0.1v and when throttle is depressed, it can climb to 0.9v, 0.8, 0.7 and so on but it hardly stays steady, it hovers up and down.

I had to read the maf too and sometimes it can climb to 28g /s and stays at 3g/s when idling.

I need people that are better informed here to help me ascertain from these readings if anything is amiss or could the cat itself be the problem?

Help needed pls.