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Water-electrolysis intends a favorable green technology to hold the worldwide energy and ecological disaster, but its efficacy is significantly restricted by the slow reaction kinetics of both the anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). Herein, the fabrication of multi-cation incorporated Fe2+/3+/Co2+ species into selenides nanorods (Fe@Co/Se 2 -NRs) and corresponding analysis of their catalytic activity for electrochemical (EC) and solar-driven water splitting as a purpose of the composition are reported. This efficient approach can fabulously endow electronic structure modulation and the direct evidence of electron-transfer-route between transition-metals and selenides, which are vital to improving the electrocatalytic activity, has never been confirmed before. For the first time, we explored the electron-transfer route of intensely-coupled Fe@Co/Se 2 -NRs catalyst, in which the Fe2+/3+/Co2+ species strongly-coupled to selenide through the Fe-coordinated Co-bridged-bond. Finally, density functional theory calculations disclose that the multi-cation doping effects into selenides are vital for enhanced electrocatalytic performance. [Display omitted] • The self-templated approach developed for bifunctional OER/HER electrocatalysts. • Iron-Cation-Coordinated Cobalt-Bridged-Selenides Nanorods structure increases the number of active sites. • The Fe@Co/Se 2 -nanorods reveal superior bifunctional OER/HER performance. • Requires only 1.5 V@10 mA cm−2 for electrochemical and solar-to-hydrogen conversion efficacy of ∼ 7.0% for water splitting. • DFT and XAS analysis exposed the electron-transfer route of intensely coupled Fe@Co/Se 2 -NRs. [ABSTRACT FROM AUTHOR]

Electrocatalytic urea oxidation reaction (UOR) with a low thermodynamic potential is a perfect substitute for anodic oxygen evolution process (OER) in the effective generation of hydrogen. However, because of the slow kinetics of UOR, its potential application for commercial use remains untapped. Nickel-based materials may be an option for urea oxidation reaction but the heavily filled d orbital prevents enhanced adsorption and activity. Here, taking into account the adsorption-energy scaling limitations, Co3+ with partially filled d orbital is introduced into nickel selenide to form a heterointerface catalyst (2D CoSe 2 /Ni 0.85 Se) that enhances UOR. As anticipated, the 2D CoSe 2 /Ni 0.85 Se electrode displays a low potential of 1.33 V to achieve 100 mA cm−2 for UOR while retaining strong durability for 300 h. Further, 2D CoSe 2 /Ni 0.85 Se catalyst is used as an anode in an anion exchange membrane flow electrolyzer, which achieved an industrial-level voltage of 1.91 V at 1 A cm−2 and robust durability. [Display omitted] • We constructed a cost-efficient 2D CoSe 2 /Ni 0.85 Se heterointerface. • The synergistic effect within 2D CoSe 2 /Ni 0.85 Se enhances catalytic activity. • The 2D CoSe 2 /Ni 0.85 Se heterointerface exhibits superior catalytic performance toward UOR. • A single cell AEM flow electrolyzer was constructed and tested. • In situ IRRAS was utilized to identify reaction interfaces for UOR. [ABSTRACT FROM AUTHOR]