Okra-like hollow Cu0.15-CoP/Co3O4@CC nanotube arrays catalyst for overall water splitting

Abstract

The manufacture of hydrogen energy by overall water splitting (OWS) has been broadly considered as a promising candidate for constant energy systems. Herein, we report an okra-like hollow Cu0.15-CoP/Co3O4@CC nanotube arrays catalyst through a simple hydrothermal-phosphating method. As a noble-metal-free catalyst, it exhibits outstanding HER (hydrogen evolution reaction) catalytic activity with an overpotential of 13 mV to achieve 10 mA cm−2 in 1 M KOH electrolyte. For OER (oxygen evolution reaction), it demands 225 mV to achieve 10 mA cm−2. When okra-like hollow Cu0.15-CoP/Co3O4@CC is used as both cathode and anode electrode materials, 1.487 V is required to reach 10 mA cm−2 for OWS, better than numerous electrocatalysts that have been reported. Moreover, it displays excellent stability in a continuously 60 h i-t test, proving an enormous potential for large-scale applications. The theoretical calculation of density functional theory (DFT) further reveals that Cu doping can bring localized structure polarization and reduce the hydrogen adsorption free energy (ΔGH∗) on the interstitial sites, thus leading to a significant increase in catalytic activity.