Self-supported hierarchical CuO_x@Co₃O₄heterostructures as efficient bifunctional electrocatalysts for water splitting

Abstract

The hierarchical CuOx@Co3O4catalyst shows notable OER and HER activities in an alkaline environment.

Self‐Supported Electrocatalysts for Efficient Oxygen Evolution Reaction: Hierarchical CuOx@CoO Nanorods Grown on Cu Foam

“…The HRTEM image chosen on the core surface featured the lattice fringes of 0.215 nm and 0.217 nm, matching with the (111) and the (200) plane of CuO, respectively, and the lattice fringe space of 0.166 nm kept consistent with the (110) facet of Cu 2 O . This result demonstrated the presence of heterojunction between CuO and Cu 2 O in CuO x nanorod surface . In addition, the HRTEM images marked at the shell part presented a interfinger distance of 0.203 nm, corresponding to (111) planes of CoO .…”

“…In contrast, the bonding energy of Co 2p 3/2 for CuO x @CoO showed a negative shift (about 0.2 eV). These conclusions suggested increasing electron density of Cu atoms and decreasing electron density of Co atom in CuO x @CoO, and further explained the existence of electronic reciprocity between CuO x and CoO, resulted in enhancing electronic conductivity of CuO x @CoO …”

“…In fact, forming an intelligent configuration of core-shell structure on the surface of conductive carriers is a promising strategy for solving these problems. [18] Copper hydroxide (Cu(OH) 2 ) has been proven to be active catalytically for OER. [9a] Zhou et al reported Cu(OH) 2 nanorods as bases to grow Co-layer double hydroxide.…”

“…Benefitting from the synergetic effect between CuO x (representing the CuO and Cu 2 O phases) core and Co 3 O 4 shell derived from the hierarchical core-shell configuration, the catalyst exhibited excellent electrocatalysis. [18] The development of self-supported electrodes is an effective method to improve the activity of the electrodes. [19] Generally, the self-supported catalyst of the nanoarray deposited on the surface of the support can gain the extra advantage of releasing oxygen and carrier transport from the electrode surface, [20] and enhance interaction and synergistic effect.…”

“…[19] Generally, the self-supported catalyst of the nanoarray deposited on the surface of the support can gain the extra advantage of releasing oxygen and carrier transport from the electrode surface, [20] and enhance interaction and synergistic effect. [18] Inspired by the above, we integrated Cu(OH) 2 nanorods vertically grown on Cu foam. The rod-shaped Cu(OH) 2 served as a skeleton to provide a direct template for the ZIF-67 polyhedron to grow on, obtaining a precursor of Cu(OH) 2 @ZIF-67 on CF.…”