Superassembly of NiCoOx Solid Solution Hybrids with a 2D/3D Porous Polyhedron-on-sheet Structure for Multi-functional Electrocatalytic Oxidation

Preparation of highly active electrocatalysts with good stability is very important on environment pollution treatment and organic oxidation. Herein, we highlight an advanced multi-functional electrocatalyst based on NiCoOx solid solution hybrids with hierarchical architecture and high porosity. The 2D nanosheets grafting with 3D polyhedrons possess large specific surface area, higher ratio of surface area-to-volume, more edge active sites and excellent structure stability to boost catalytic activities. The high porosity can enrich more active sites and ensure ions permeation channels for facile mass transport. The close contact between (Ni, Co)O and (Ni, Co)3O4 allows facile charge transport, contributing to the favorable reaction kinetics with the synergy of phase engineering between (Ni, Co)O and (Ni, Co)3O4. Importantly, DFT calculations have proved that Ni incorporation can not only optimize the electronic structure to enhance the electrical conductivity and charge transfer, but also downshift the d-band center from the Fermi level to facilitate the desorption of oxygen intermediates, resulting in improved activity. As a result, the optimal NiCoOx solid solution hybrids present excellent catalytic performances on UOR as well as the electro-oxidation of organic molecules.