Robust dual-heterojunction Pt/CeO2-Ni(OH)2 bifunctional electrocatalyst toward efficient overall water splitting

Tailoring efficient bifunctional electrocatalyst with dual-heterojunction is crucial for overall water splitting (OWS). Herein, a multicomponent bifunctional catalyst with dual-heterojunction is rapidly constructed via sequential electrodeposition for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory (DFT) calculations reveal that bidirectional electron transfer at the interface induces a double built-in electric field (BIEF) in Pt/CeO 2 -Ni(OH) 2 , which offers additional impetus for electron transport and brings the d -band center closer to the Fermi level, thereby optimizing reaction kinetics and the adsorption of reaction intermediates. Active Pt and CeO 2 nanoparticles (NPs) are uniformly anchored on the stable Ni(OH) 2 nanoflocs, ensuring high exposure of active sites and preventing NPs aggregation. Meanwhile, Ni(OH) 2 , serving as abundant electron donor center, forms dual heterointerface with Pt and CeO 2 (Pt-Ni(OH) 2 and CeO 2 -Ni(OH) 2 ), which ensures structural stability during electrochemical processes. Benefiting from the dual-heterojunction and the unique structure design, Pt/CeO 2 -Ni(OH) 2 exhibits excellent electrocatalytic performance, requiring only 66 mV (10 mA cm −2 ) and 278 mV (100 mA cm −2 ) for HER and OER, respectively. Remarkably, the two-electrode electrolyzer based on Pt/CeO 2 -Ni(OH) 2 electrode requires only 1.49 V to deliver 10 mA cm −2 with an excellent durability for OWS. This work brings light to the rational design and directional construction of bifunctional electrocatalyst hybrid nanomaterials with multiple heterojunctions.