Universal preparation method for in-situ growth of layered double hydroxide (LDH) layer on substrate surface

A universal preparation method for in-situ growth of a layered double hydroxide (LDH) layer on a substrate surface, comprising the following steps:

• (1) mixing a divalent metal nitrate, a trivalent metal nitrate, and water to obtain a mixed solution;
• (2) constructing a three-electrode system using the mixed solution obtained in step (1) as an electrodeposition solution and a substrate as a working electrode, and conducting electrodeposition to obtain a deposited substrate;
• (3) mixing the divalent metal nitrate, the trivalent metal nitrate, water, and ammonia water to obtain a hydrothermal reaction solution;
• and
• (4) mixing the deposited substrate obtained in step (2) with the hydrothermal reaction solution obtained in step (3), and then conducting a hydrothermal reaction to obtain an LDH protective layer-containing substrate;
• wherein
• there is no time sequence between steps (3) and (1),
• in step (1), the divalent metal nitrate in the mixed solution has a concentration of 40 mmol/L to 50 mmol/L;
• and
• in step (2), the electrodeposition is conducted at a voltage of −1.2 V to −1.4 V for 200 sec to 800 sec.