FeOOH-enhanced bifunctionality in Ni3N nanotube arrays for water splitting

Here we report the functional FeOOH as a cocatalyst to enhance excellent bifunctionality of the Ni3N catalyst, which demonstrate remarkable electrocatalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reduction (OER) compared to the pristine Ni 3 N sample. Experimental data and theoretical calcinations demonstrate that the FeOOH facilitates surface adsorption and cleavage of OH-/H2O species and decrease the d-band center of active Ni species for optimizing the Gibbs free energy of intermediates. Furthermore, relatively vertical Ni3N nanotubes can promote the mass transport and electrons transfer as a main catalyst. The unusual synergistic effect in hybrid system with high density of heterointerface is contributed to the improvement of HER/OER catalytic performance. Specifically, the obtained FeOOH/Ni3N hybrid catalysts display excellent OER/HER performance with an overpotential of 244 mV/67 mV at 10 mA cm(-2) in 1.0 M KOH, along with an applied potential of 1.58 V to boost overall water splitting at 10 mA cm(-2). This simple and effective strategy may provide a new path to design the bifunctional catalysts and improve the catalytic performance for water splitting.