Enhancing the d/p‐Band Center Proximity with Amorphous‐Crystalline Interface Coupling for Boosted pH‐Robust Water Electrolysis

Abstract

Electrocatalytic splitting of water holds the fossil-free premise for H 2 production, which couples cathodic hydrogen and anodic oxygen evolution reactions (HER/OER). [1] Kinetically driving water electrolysis (WE) requires efficient and stable catalysts to reduce the overpotentials for both HER and OER. [2] During practical WE operations, the electrolyte's pH change is a critical challenge for the activity and stability retention of the electrocatalysts. [3] Therefore, there is an urgent need to develop robust electrocatalysts for wide pH conditions to ensure work efficiency and reduce usage costs. Although Pt-group metals are endowed with active and pH-robust HER/OER properties, the costliness and scarcity greatly limit their sustainable deployments in WE. [4] In this regard, rationalizing non-precious pHrobust catalysts is the top priority of current research for water splitting. Electronic level adjustment is the fundamental technique for the rational design of advanced non-precious catalysts. [5] As known, the d-band (ε d ) and p-band center (ε p ) to Fermi level can well reflect the intermediates' adsorption energies and activation energy barriers during HER/ OER catalysis. [6] Currently, the d-band center level of 3d-metal sites is widely considered to be effective descriptors for HER and OER. [5a] However, the metal sites are not the actual active catalytic centers in some systems, [6c] and the p-band center of non-metal atoms should be revisited together with ε d . Hence, the synergic tuning of d/p-band center will be the design criterion for the innovation of economic, robust, and efficient WE catalysts.Interface engineering is deemed as an effective measure to achieve the d-band center regulation in terms of the interfacial charge transfer between the components. [7] In addition, the heterostructure can exhibit the protection and lattice confinement effect on the surface active atoms, modifying the stability and electronic structure by lattice distortion. [8] Current reports on transition metal heterostructures are mainly crystalline-crystalline complexes, and the interfacial atomic distortion will be hindered by lattice resistance or structural rigidity to some extent. [9] In this context, the establishment of an amorphous-crystalline Rationalizing non-precious pH-robust electrocatalysts is a crucial priority and required for multi-scenario hydrogen production customization. Herein, an amorphous-crystalline CoBO x /NiSe heterostructure is theoretically profiled and constructed for efficient and pH-robust water electrolysis. The crystalline lattice confinement induces a CoCo bond shortening and a B-site delocalization on amorphous CoBO x , resulting in a decreased d-p band center difference (Δε d-p ) toward the balanced intermediates adsorption/desorption. Accordingly, the CoBO x /NiSe heterostructure exhibits efficient and robust hydrogen/oxygen evolution reaction (HER/OER) catalytic activity in different electrolytes. Of particular note, it achieves ultralow overpotentials in both the beyon...

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