Insights into the synergistic effect of multi-walled carbon nanotube decorated Mo-doped CoP2 hybrid electrocatalysts toward efficient and durable overall water splitting

Abstract

In this work, a series of Mo_xCo_1−xP₂/MWCNT (x = 0.25, 0.29 and 0.33) composite electrocatalysts have been designed and successfully fabricated, and their utility as remarkable, active and stable electrocatalysts is reported for the first time. The Mo_xCo_1−xP₂/MWCNT composite electrocatalysts with controllable morphology and composition are created by changing the molar ratios of Mo : Co precursors. Mo_0.29Co_0.71P₂/MWCNTs exhibits the best hydrogen evolution (HER) and oxygen evolution reaction (OER) performance with low overpotentials of 85 and 220 mV in 1.0 M KOH, respectively. Impressively, a cell voltage of 1.48 V at a current density of 10 mA cm⁻² for overall water splitting has been realized by using Mo_0.29Co_0.71P₂/MWCNTs as both the cathode and anode material, which is one of the lowest potentials for practical overall water splitting. Experimental and density functional theory results suggest that such excellent electrocatalytic performance may stem from the synergistic effect between Mo_0.29Co_0.71P₂ and MWCNTs.