Kirkendall effect Strengthened-Superhydrophilic/superaerophobic Co-Ni3N/NF heterostructure as electrode catalyst for High-current hydrogen production

The development of efficient electrocatalysts for large-scale water electrolysis is crucial and challenging. Research efforts towards interface engineering and electronic structure modulation can be leveraged to enhance the electrochemical performance of the developed catalysts. In this work, a surface-engineered Co-Ni3N/NF heterostructure electrode was prepared based on Kirkendall effect for high-current water elec-trolysis. In the experiments, the textural feature and intrinsic activity of the Co-Ni3N/NF heterostructure were tuned through cobalt-doping and the creation of structural defects. As a result, the increased surface energy endowed Co-Ni3N/NF heterostructure with superhydrophilic and superaerophobic properties. Meanwhile, the contact area of the gas-liquid-solid three phases was optimized. With a large underwater bubble contact angle (CA) of 169 degrees, the electrolyte solution can infiltrate the Co-Ni3N/NF electrode within 150 ms. Sequentially, the generated gas bubbles were able to detach at high frequency, which ensured the rapid mass exchange. The performance tests showed that the optimal Co-Ni3N/NF electrode sample reached current densities of 100 mA cm-2 and 500 mA cm-2 at the overpotentials of 98 mV and 123 mV, respectively. Benefiting from the reduction of hydrogen embrittlement, the HER performance of the pre-pared Co-Ni3N/NF electrode sample decreased slightly after 100 h durability test, but the overall structure remained well. Those results allowed us to conclude that the prepared Co-Ni3N/NF electrocatalyst holds the promises for large-scale water electrolysis in industries. More specifically, this work provided a new per-spective that the efficiency of electrocatalysts for large-scale water electrolysis can be enhanced by con-structing a heterostructure with good wettability and gas repellency.(c) 2023 Elsevier Inc. All rights reserved.

Automated summary

Efficient electrocatalysts for large-scale water electrolysis are crucial and challenging. In this study, researchers prepared a surface-engineered Co-Ni3N/NF heterostructure electrode with superhydrophilic and superaerophobic properties, optimized gas-liquid-solid three-phase contact area, and achieved high current densities. The results demonstrate that constructing a heterostructure with good wettability and gas repellency can enhance the efficiency of electrocatalysts for large-scale water electrolysis.