ABSTRACT
In the process of oxygen evolution reaction (OER) on perovskite, it is of great significance to accelerate the hindered lattice oxygen oxidation process to promote the slow kinetics of water oxidation. In this paper, a facile surface modification strategy of nanometer-scale iron oxyhydroxide (FeOOH) clusters depositing on the surface of LaNiO3 (LNO) perovskite is reported, and it can obviously promote hydroxyl adsorption and weaken Ni-O bond of LNO. The above relevant evidences are well demonstrated by the experimental results and DFT calculations. The excellent hydroxyl adsorption ability of FeOOH-LaNiO3 (Fe-LNO) can obviously optimize OH- filling barriers to promote lattice oxygen-participated OER (LOER), and the weakened Ni-O bond of LNO perovskite can obviously reduce the reaction barrier of the lattice oxygen participation mechanism (LOM). Based on the above synergistic catalysis effect, the Fe-LNO catalyst exhibits a maximum factor of 5 catalytic activity increases for OER relative to the pristine perovskite and demonstrates the fast reaction kinetics (low Tafel slope of 42 mV dec-1) and superior intrinsic activity (TOFs of ~40 O2 S-1 at 1.60 V vs. RHE).
ABSTRACT
Searching for a highly efficient electrocatalyst for the hydrogen evolution reaction (HER) in alkaline solution is still challenging. In this work, we report a HER electrocatalyst composed of Ni foam, Ni3S2, and nitrogen-doped carbon nanotubes (NF@Ni3S2@NCNTs). The good lattice matching between Ni and Ni3S2, interstitial doping of C and N atoms, and synergistic effect of NCNTs make NF@Ni3S2@NCNTs highly efficient HER electrocatalysts in alkaline solution. NF@Ni3S2@NCNTs exhibit an overpotential of 93.89 mV at a current density of 10 mA cm-2, a Tafel slope of 54 mV dec-1, and superior stability for HER in 1 M KOH solution. Our findings will promote the reasonable design and synthesis of an efficient electrocatalyst for HER in alkaline electrolytes.
