Heterogeneous interface mismatch-manipulated ruthenium-immobilized binary metal phosphide-layered 2D V2CTx for high-efficiency water electrolysis
Deepanshu Malhotra, Duy Thanh Tran, Sampath Prabhakaran, Do Hwan Kim, Nam Hoon Kim, Joong Hee Lee
Abstract
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.