2D/2D Heterojunction of Ni-Co-P/Graphdiyne for Optimized Electrocatalytic Overall Water Splitting

摘要

The development of efficient catalysts for water splitting in alkaline condition is central to produce hydrogen for renewable energy storage. Herein, we fabricated a new 2D/2D heterojunction via directly electrodepositing of ternary Ni-Co-P nanosheets on graphdiyne (GDY) nanowalls. Benefiting from the synergistic interaction between Ni-Co-P and GDY, Ni-Co-P/GDY shows obviously improved activity for electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), realizing a large current density of 300 mA/cm(2) for HER at low overpotential of 313 mV, much lower than that of commercial 20 wt% Pt/C (430 mV), and a much better OER performance than the commercial RuO2. A small cell voltage of 1.60 V is sufficient to achieve the standard 10 mA/cm(2) current density by Ni-Co-P/GDY as a bifunctional electrode for water splitting in 1.0 M KOH solution. Raman, XPS and Surface valence band photoemission spectroscopic measurements confirm that the GDY-incorporation strategy optimizes the electronic structure of the Ni-Co-P and thus promotes its electrocatalytic activity.