Decoupling Bubble Nucleation from Catalysis to Boost Cu_xO/NiO Electrocatalytic Water Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient water splitting demands low overpotentials and reduced bubble resistance at high current densities.
• Existing methods face challenges where bubble management conflicts with catalysis, hindering mass transfer and site accessibility.

Purpose of the Study:

• To minimize overpotentials in electrochemical water splitting.
• To decouple bubble release from catalytic activity for enhanced performance.
• To enable rational design of electrocatalytic systems for high-current density operation.

Main Methods:

• Embedding CuₓO nucleation promoters in NiO nanosheet arrays.
• Electrochemical measurements to assess overpotential.
• Operando high-speed imaging and deep learning for bubble dynamics analysis.
• Density Functional Theory (DFT) and Monte Carlo simulations for mechanistic insights.

Main Results:

• Drastically reduced activation and mass transfer overpotential observed.
• Quantified accelerated O₂ bubble dynamics at the CuₓO/NiO/NF interface.
• CuₓO identified as an O₂ bubble nucleation site and catalytic promoter.

Conclusions:

• The bubble-catalysis-decoupling methodology effectively enhances electrochemical water splitting.
• CuₓO/NiO/NF achieves a current density of 3 A cm⁻² at 2.13 V.
• This approach provides mechanistic insights for designing advanced electrocatalysts for high-current applications.