3D Carbon Electrode with Hierarchical Nanostructure Based on NiCoP Core‐Layered Double Hydroxide Shell for Supercapacitors and Hydrogen Evolution. Issue 12 (16th June 2021) - Duan, Cunpeng
Abstract: Currently, the development of self‐supported and low‐cost earth‐abundant electrocatalysts with well‐defined nanostructure has shown significant potential in energy‐related storage and electrocatalytic reactions. Herein, a three‐dimensional (3D) self‐supporting electrode NiCoP@NiCo LDH/CC (NCP@NCH/CC) constructed with NCP@NCH core‐shell nanostructures and carbon cloth as substrate has been developed via the hydrothermal and subsequent electrodeposition process. The obtained 3D electrode with 1D NiCoP nanowires (NWs) core and 2D NiCo LDH nanosheets shell can exhibit superior electrochemical performance and remarkable stability for the pseudocapacitive reaction and hydrogen evolution reaction (HER), even comparable to the best reported transition metal phosphides (TMP) electrodes. It reveals an ultra‐high area specific capacitance (9.4 F/cm 2 at 10 mA/cm 2 in 3 M KOH electrolyte), outstanding capacitance retention (74.12 % from 10 to 60 mA/cm 2 ) and excellent cycling stability (93.51 % of original capacitance was retained after 5000 cycles at 50 mA/cm 2 ) as supercapacitor electrode material. For HER in alkaline media, it can demonstrate an overpotential of 182 mV at 10 mA/cm 2 and Tafel slope of 82 mV/ dec in 1 M KOH. For HER in acidic electrolyte, it can exhibit an overpotential of 141 mV at 10 mA/cm 2 and Tafel slope of 82 mV/ dec in 0.5 M H2 SO4 . The electrochemical performance enhancement can be ascribed to the core‐shell NiCoP@NiCo LDH nanostructure anchored on the carbon and synergistic effect with the carbon cloth in 3D electrode. Our present work provides a facile strategy to construct 3D TMP‐based carbon electrode with core‐shell nanostructures, demonstrating a great promise for storage processes and energy conversion. Abstract : A three‐dimensional self‐supporting NCP@NCH/CC nanostructure electrode material is prepared by simple one‐step electrodeposition of an NiCo layered double hydroxide (LDH). Based on the synergistic effect of the nickel‐cobalt double transition metal and the electron delocalization effect of P, a smaller size and a larger number of NiCoP nanowires provide more electron‐transmission channels for the pseudo‐capacitance reaction, the introduced NiCo LDH nanosheets provide more active sites for ion reactions. By means of structural features, NCP@NCH/CC electrode materials have considerable prospects for applications in supercapacitors and the hydrogen evolution reaction.