Enhanced water-splitting performance: Interface-engineered tri-metal phosphides with carbon dots modification

Abstract

Designing integrated overall water-splitting catalysts that maintain high efficiency and stability under various conditions is an important trend for future development, yet it remains a significant challenge. Herein, novel nanoflower-like tri-metallic Ni–Ru–Mo phosphide catalyst ((Ni–Ru–Mo)P@F-CDs), integrated with F-doped carbon dots (F-CDs), were synthesized via a straightforward hydrothermal process and subsequent phosphatization. Attributable to precise interface engineering and electronic structure optimization, (Ni–Ru–Mo)P@F-CDs exhibit exceptional bi-functional catalytic activity in alkaline conditions, achieving remarkably low overpotentials of 231 and 123 mV for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, at a current density of 100 mA cm^–2. Industrially, only 1.426 V is needed for the same efficacy. Additionally, the catalyst requires merely 1.508 and 1.564 V for overall water splitting in 1 M KOH and simulated seawater, respectively, at 100 mA cm^–2. The catalyst also shows excellent stability, with minimal performance decline over 100 h within 100–200 mA cm^–2. Density functional theory calculations indicate that the interface structure synergistically optimizes Gibbs free energy for H* and O* intermediates during HER and OER, respectively, accelerating electrochemical water-splitting kinetics.

Keywords

DFT / hetero-structure / interface engineering / overall water splitting / phosphide

Author summay

Yingnan Jiang and Jingkun Yu contributed equally to this study.