In the reaction system, first add 4mL of a mixed solution of 0.1mL·L-1 sulfuric acid and 0.5mL·L-1 sodium sulfate solution with a volume ratio of 1: 9 as a supporting electrolyte
The mixed solution of 0.1ml · L-1 sulfuric acid and 0.5ml · L-1 sodium sulfate with a volume ratio of 4ml to 1:9 was added to the reaction system as the supporting electrolyte