Single Precursor-Derived Sub-1 nm MoCo Bimetallic Particles Decorated on Phosphide–Carbon Nitride Framework for Sustainable Hydrogen Generation

Abstract

The strategic design and fabrication of efficient electrocatalysts are pivotal for advancing the field of electrochemical water splitting (EWS). To enhance EWS performance, integrating non-noble transition metal catalysts through a cooperative double metal incorporation strategy is important and offers a compelling alternative to conventional precious metal-based materials. This study introduces a novel, straightforward, single-step process for fabricating a bimetallic MoCo catalyst integrated within a three-dimensional (3D) nanoporous network of N, P-doped carbon nitride derived from a self-contained precursor. The subsequent carbonization at 550 °C yields a highly effective bimetallic phosphide carbon nitride electrocatalyst, denoted as MoCoPCN, tailored explicitly for EWS. The MoCoPCN electrocatalyst demonstrates exceptional electrocatalytic performance, with a low onset potential of 1.43 V and an overpotential value of 202 mV at a current density of 10 mA/cm² for the oxygen evolution reaction (OER) and 49.5 mV for the hydrogen evolution reaction (HER), respectively. Moreover, the catalyst exhibits a high electrochemically active surface area of 2720 cm^–2, a small Tafel slope of 47.5 mV dec^–1 for HER and 45.7 mV dec^–1 for the OER, and a low charge transfer resistance of 0.09 Ω for the HER and 0.805 Ω for the OER. The optimal catalyst was tested for overall water splitting performance in a 1 M KOH electrolyte, demonstrating excellent efficiency with a low cell voltage of 1.49 V required to achieve a current density of 10 mA/cm². These outstanding characteristics, combined with the synergistic effects arising from the interaction between MoCo and P-g-C₃N₄ (PCN), underscore the potential of a bimetallic phosphide carbon nitride material as a highly promising electrocatalyst for efficient water splitting.