Structural and Phase Engineering of a Hierarchical 2D–2D Nickel MOF/Hydroxide‐Derived Ni<sub>0.85</sub>Se/NiTe<sub>2</sub> Heterointerface for Robust HER, OER, and Overall Water Splitting
Ishwor Pathak, Sampath Prabhakaran, Debendra Acharya, Kisan Chhetri, Alagan Muthurasu, Yagya Raj Rosyara, Taewoo Kim, Tae Hoon Ko, Do Hwan Kim, Hak Yong Kim
Abstract
Abstract The development of a nonnoble metal‐based cost‐effective, efficient, and durable bifunctional electrocatalyst is crucial to achieving the goal of carbon neutrality. In this study, a structural and interfacial engineering approach is employed to design a 2D–2D hierarchical nickel MOF/nickel hydroxide‐derived nickel selenide/nickel telluride dual‐phase material through a single‐step selenotellurization process. The rational design of highly ordered nanoarchitectures provides well‐defined voids and ample pathways for ion diffusion. Furthermore, hierarchical nickel selenide/nickel telluride works synergistically at heterojunctions, providing a local ion enrichment mechanism for the catalytic process. As a result, Ni 0.85 Se/NiTe 2 @Ni‐NH@CC needs an overpotential of 69 and 240 mV to deliver a current density of 10 mA cm −2 for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, with an outstanding stability observed for over 100 h. Moreover, the Ni 0.85 Se/NiTe 2 @Ni‐NH@CC (+, −) device exhibits excellent overall water‐splitting performance with a cell voltage of 1.50 V at 10 mA cm −2 and can be operated steadily for >100 h at 100 mA cm −2 . Density functional theory (DFT) calculations indicate favorable kinetics for H‐adsorption at the selenotelluride heterojunction, thereby promoting the HER. This work highlights a new approach for designing a unique nanoarchitecture of MOF/hydroxide‐derived selenotelluride heterojunctions for high‐efficiency energy conversion applications.