Novel three-dimensional Ni2P-MoS2 heteronanosheet arrays for highly efficient electrochemical overall water splitting

ABSTRACT Nowadays, it is still a great challenge to explore highly active and stable noble-metal-free electrocatalysts for sustainable overall water splitting. In this work, a novel electrode of three-dimensional network-like Ni2P-MoS2 heterogeneous nanosheet arrays on carbon cloth (HNSAs/CC) was designed and fabricated by a two-step strategy. Benefiting from the unique 3D hierarchical architecture, large specific surface area, synergistic effects between Ni2P and MoS2, and the support of highly conductive carbon cloth, the obtained electrode exhibits superior electrocatalytic activity for hydrogen and oxygen evolution reaction (HER and OER) in 1 mol·L-1 KOH aqueous solution with extremely low overpotentials of 78 and 258 mV respectively to deliver a current density of 10 mA·cm-2. The electrocatalytic system assembled with the obtained Ni2P-MoS2 HNSAs/CC sample as both anode and cathode for overall water splitting requires an impressively low onset potential of only 1.574 V to attain a current density of 10 mA·cm-2 and displays an excellent long-term stability. According to density functional theory calculation, the enhanced water splitting activity could be mainly attributed to the modified interfacial electronic structures and the enhanced thermoneutral adsorption of absorbates on the surface of Ni2P (110) - MoS2 (100) heterostructure. The calculated theoretical overpotentials for HER and OER based on Ni2P (110) - MoS2 (100) heterostructure are 0.019 and 0.279 V, respectively. The facile synthesis method and insights into the HER and OER active interfaces reported here will advance the development of high-performance bifunctional overall water splitting electrocatalysts.