RATIONAL DESIGN OF HIERARCHICAL MN/CO-NI/CO LAYERED DOUBLE HYDROXIDE HETEROSTRUCTURES AS BIFUNCTIONAL ELECTROCATALYSTS FOR HIGHLY EFFICIENT OVERALL WATER SPLITTING

Abstract

The growing need for clean and renewable energy has stimulated many studies on efficient hydrogen generation by water splitting. Here, we successfully designed and prepared a hierarchical Mn/Co–Ni/Co layered double hydroxide heterostructure as a bifunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The Mn/Co–Ni/Co heterostructure offers a potential approach to surpass the drawbacks of monometallic catalysts.

Structural and morphological analyses revealed the successful construction of a porous nanosheet-like structure with a large surface area and active sites. The intimate interaction between Mn, Co and Ni improves the electronic properties and facilitates charge transfer. These characteristics play a vital role in enhancing the performance and catalytic activity.

Electrochemical testing revealed that the Mn/Co–Ni/Co heterostructure has a low overpotential, low charge transfer resistance, and fast reaction kinetics compared to the individual Mn/Co and Ni/Co materials. Manganese provides extra redox sites, while nickel and cobalt enhance the conductivity and catalytic performance for HER and OER reactions.

 Additionally, the hierarchical architecture allows for easy electrolyte transport and fast gas release, enhancing stability and robustness. In summary, the developed heterostructure is a low-cost and highly efficient alternative to noble metal catalysts and has the potential to be used in the efficient production of hydrogen.