Heterogeneous interface mismatch-manipulated ruthenium-immobilized binary metal phosphide-layered 2D V2CTx for high-efficiency water electrolysis

Heterogeneous interface mismatch manipulated by Ru-immobilized binary metal phosphide-layered 2D V 2 CT x MXene leads to unique physicochemical properties that enhance the kinetics of both the HER and OER reactions. This capability has been practically demonstrated in an assembled AEMWE setup, achieving 0.5 A cm -2 at a stack voltage of 2.14 V and long-term stability exceeding 350 h. • Hetero-interfaces of Ru-immobilized binary metal phosphide-coated V 2 CT x is prepared. • The material needs a cell voltage of 1.43 V at 10 mA cm −2 in 30 wt% KOH at 90 °C. • The AEMWE device could obtain a current of 0.5 A cm −2 at a stack voltage of 2.14 V. • The AEMWE could achieve a long-term stability exceeding 350 h in alkaline medium. The development of effective electrocatalysts towards hydrogen evolution and oxygen evolution reactions (HER and OER) via water electrolysis is essential for producing green hydrogen gas, a promising fuel for modern renewable energy industries. Herein, we propose a multi-interfacial hetero-architecture that features ruthenium nanocrystals-immobilized binary metallic phosphide layer supported with two-dimensional V 2 CT x MXene nanosheets (Ru-NiCoP@V 2 CT x ) as a bifunctional catalyst. This material requires an overpotential of merely 23 mV for HER at 10 mA·cm −2 and 390.0 mV for OER at 50 mA·cm −2 in 1.0 M KOH at 25 °C, thereby enabling a cell voltage of 1.61 V to achieve 10 mA cm −2 during overall water splitting with long-term stability over 40 h. Since the two-electrode electrolyzer cell of Ru-NiCoP@V 2 CT x(+,-) couple operates in an industrial simulated condition of 30 wt% KOH electrolyte medium at a high temperature of 90 °C, it delivers a low cell voltage of 1.43 V to achieve 10 mA cm −2 during overall water splitting. A theoretical study indicates unique synergistic effects of multiphasic hybridization among Ru, NiCoP, and V 2 CT x cause the heterogeneous interface mismatch with lattice distortion to tune the electronic structure as well as increase the number of exposed active sites, thus significantly enhancing reaction kinetics. The Ru-NiCoP@V 2 CT x(+,−) is assembled into anion exchange membrane water electrolyzer cell, demonstrating an operation voltage of 2.14 [email protected] A cm −2 and a projected stability of 96 % retention after 350 h, suggesting that Ru-NiCoP@V 2 CT x has extensive potential for high-efficiency water splitting applications.