Highly Efficient Trivalent Chromium Electroplating Enabled by the Hydrogen Isotope Effect

Area of Science:

• Electrochemistry
• Materials Science
• Surface Engineering

Background:

• Conventional chromium electroplating processes exhibit low current efficiencies (10-20%) due to significant hydrogen evolution reactions (HER).
• HER leads to energy waste and can cause embrittlement of electrodeposited chromium films.
• Controlling HER is essential for developing sustainable and high-performance electroplating technologies.

Purpose of the Study:

• To achieve high current efficiency in chromium electrodeposition by selectively suppressing the HER.
• To explore the use of deuterated electrolytes and concentrated salt solutions for enhanced electroplating.
• To provide a design principle for aqueous electroplating systems leveraging the water isotope effect.

Main Methods:

• Utilized deuterated Cr(III) electrolytes in a highly concentrated CaCl2 system.
• Investigated the suppression mechanism of HER through the isotope effect of water.
• Tailored water dissociation around Cr(III) ions without organic additives.

Main Results:

• Achieved a high current efficiency of approximately 90% for crystalline chromium electrodeposition.
• Demonstrated selective suppression of HER via deuterated electrolytes and concentrated CaCl2.
• Successfully enabled efficient crystalline Cr electrodeposition by controlling water dissociation.

Conclusions:

• The study successfully enhanced chromium electroplating efficiency by suppressing HER using deuterated electrolytes.
• The findings highlight the potential of exploiting the water isotope effect for sustainable electroplating.
• A novel design principle for aqueous electroplating systems was established, offering a pathway for improved surface finishing technologies.