A, according to the right-hand rule, the current flows from point D to point C, so the current direction flows from point C to point D. Because the disc is cutting the magnetic induction line, it is equivalent to the power supply, so the potential of point D is higher than that of point C, so A is wrong and B is correct;

C, the disk can be seen as a number of radial, so there are cutting magnetic induction lines at any time, so C is correct;

D, according to Faraday's law of electromagnetic induction, there is E=BLV, so the greater the rotating speed, the greater the electromotive force and the greater the current flowing through the resistor R, so D is correct;

Therefore: alkaline catalytic decomposition ..