Tip?Enhanced Electric Field: A New Mechanism Promoting Mass Transfer in Oxygen Evolution Reactions

The slow kinetics of oxygen evolution reaction (OER) causes high power consumption for electrochemical water splitting. Various strategies have been attempted to accelerate the OER rate, but there are few studies on regulating transport reactants especially under large current densities when mass transfer factor dominates reactions. Herein, NixFe1–x alloy nanocones arrays (with ?2 nm surface NiO/NiFe(OH)2 layer) adopted boost reactants. Finite element analysis suggests that high-curvature tips can enhance local electric field, which induces an order magnitude higher concentration hydroxide ions (OH?) at active sites and promotes intrinsic activity by 67% 1.5 V. Experimental results show a fabricated NiFe nanocone array electrode, with optimized composition, has small overpotential 190 mV 10 mA cm?2 255 500 cm?2. When calibrated area, electrode outperforms state-of-the-art electrocatalysts. positive effect tip-enhanced field in promoting is also confirmed comparing samples different tip curvature radii. It suggested this enhanced generic other catalysts.