What Is an Electrolysis Cathode?

Cathode is a term for electrochemical reactions. Refers to the pole that gains electrons, that is, the pole that undergoes the reduction reaction. In a primary battery, the cathode is the positive electrode; electrons flow from the negative electrode to the positive electrode, and current flows from the positive electrode to the negative electrode. The cations in the solution move to the positive electrode and the anions move to the negative electrode. The cathode is connected to the negative pole of the power source in the electrolytic cell. The cathode always corresponds to the anode (Anode).

Cathode is a term for electrochemical reactions. Refers to the pole that gains electrons, that is, the pole that undergoes the reduction reaction. In a primary battery, the cathode is the positive electrode; electrons flow from the negative electrode to the positive electrode, and current flows from the positive electrode to the negative electrode. The cations in the solution move to the positive electrode and the anions move to the negative electrode. The cathode is connected to the negative pole of the power source in the electrolytic cell. The cathode always corresponds to the anode (Anode).

Chinese name

cathode

Foreign name

cathode

effect

One pole in galvanic cell / electrolytic cell

Composition of negative electrode of cathode galvanic cell

Negative electrode: oxidation reaction occurs

The electrons are released from the negative electrode and flow into the positive electrode along the wire through the external circuit. The cations in the electrolyte solution move to the positive electrode, and the electrons on its surface are reduced to form a closed loop. ^[1]

a. Lively different metals. The active metal is the negative electrode-zinc-copper primary battery, zinc as the negative electrode, and copper as the positive electrode; b. Metal and non-metal (non-metal must be able to conduct electricity), metal is the negative electrode-zinc-manganese dry battery, zinc as negative electrode, graphite As positive

c. Metals and compounds, metal is the negative electrode-lead storage battery, lead plate as the negative electrode, lead dioxide as the positive electrode;

d. The inert electrode is essentially a hydrogen-negative electrode, a hydrogen-oxygen fuel cell, and the electrodes are all platinum.

Composition of negative electrode of cathode electrolytic cell

Electrolysis: The process of passing a current through an electrolyte solution to cause a redox reaction at the yin and yang levels.

Electrolysis cell: A device that converts electrical energy into chemical energy by means of an oxidation-reduction reaction, such as electrolytic saturated saline.

Cathode reduction reaction

The electrons flow from the negative electrode of the external power supply, flow to the cathode of the electrolytic cell, and then flow back from the anode to the positive electrode of the power supply. ^[2]

Cathode: Connected to the negative pole of the power supply. It is the cations in the solution that undergo the reduction reaction on the cathode. When multiple cations are present in the solution, the more inactive the metal, the more oxidative the cations are, and the easier it is to be reduced, in the order of metal activity. In aqueous solutions, cations of metals before aluminum cannot be reduced.

The concept and measures of cathodic protection

Definition 1: An electrochemical protection method to obtain anti-corrosion effect by reducing the corrosion potential. Applied disciplines: ship engineering (level one discipline); ship corrosion and protection (level two disciplines)

Definition 2: Use the protected metal as the cathode, apply external current for cathodic polarization, or use a corrosive metal with a low electrochemical sequence as the sacrificial anode to reduce or prevent metal corrosion. Applied disciplines: marine technology (first-level discipline); marine technology (second-level discipline); marine water resources development technology (third-level discipline)

Definition 3: Electrochemical protection by reducing the corrosion potential. Applied disciplines: mechanical engineering (first-level discipline); corrosion and protection (second-level discipline); electrochemical corrosion (third-level discipline)

Cathodic protection technology is a kind of electrochemical protection technology. Its principle is to apply an external current to the surface of the metal structure to be corroded, and the structure to be protected becomes the cathode, so that the electron migration of metal corrosion is suppressed, and the corrosion is avoided or weakened. occur. ^[3]