Biomimetic design of ultrathin edge-riched FeOOH@Carbon nanotubes as high-efficiency electrocatalysts for water splitting

Abstract Based on a plant-like morphology, here, we report a multidimensional composite with ultrathin edge-riched FeOOH "leaves" growing on carbon nanotube "branches" (FeOOH@CNTs) via a facile and environmentally benign approach. A Fenton reaction was adopted to oxidize carbon nanotubes (CNTs), and FeOOH flakes were generated on the CNTs as reaction proceeded. The highly conductive CNT "branches" ensure rapid electron transmission and compensate for low conductivity of the FeOOH "leaves". Meanwhile, ultrathin FeOOH "leaves" growing on CNT "branches" expose sufficient numbers of active sites for oxygen evolution reaction (OER). Density functional theory (DFT) computational results indicate that FeOOH@CNTs exhibit better OER catalytic performance than FeOOH. To achieve water splitting, FeOOH@CNTs were deposited on nickel foam as an anode, with platinum (Pt) sheet used as a cathode. A low cell voltage of only 1.44 V was achieved to yield a current density of 10 mA cm–2 with a TOF of 12.50 s-1.