| Affiliation: | 1. School of Materials Science and Engineering, Key Laboratory of Advanced Ceramics and Machining Technology of the Ministry of Education, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 P. R. China;2. School of Materials Science and Engineering, Key Laboratory of Advanced Ceramics and Machining Technology of the Ministry of Education, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin University, Tianjin, 300072 P. R. China Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 USA;3. Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 USA;4. Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong Innovation Campus, Squires Way, North Wollongong, NSW, 2522 Australia;5. School of Materials Science and Engineering, Hebei University of Technology, Tianjin, 300132 P. R. China |
| Abstract: | Constructing heterostructures with abundant interfaces is essential for integrating the multiple functionalities in single entities. Herein, the synthesis of NiSe2/CoSe2 heterostructures with different interfacial densities via an innovative strategy of successive ion injection is reported. The resulting hybrid electrocatalyst with dense heterointerfaces exhibits superior electrocatalytic properties in an alkaline electrolyte, superior to other benchmarks and precious metal catalysts. Advanced synchrotron techniques, post structural characterizations, and density functional theory (DFT) simulations reveal that the introduction of atomic-level interfaces can lower the oxidation overpotential of bimetallic Ni and Co active sites (whereas Ni2+ can be more easily activated than Co2+) and induce the electronic interaction between the core selenides and surface in situ generated oxides/hydroxides, which play a critical role in synergistically reducing energetic barriers and accelerating reaction kinetics for catalyzing the oxygen evolution. Hence, the heterointerface structure facilitates the catalytic performance enhancement via increasing the intrinsic reactivity of metallic atoms and enhancing the synergistic effect between the inner selenides and surface oxidation species. This work not only complements the understanding on the origins of the activity of electrocatalysts based on metal selenides, but also sheds light on further surface and interfacial engineering of advanced hybrid materials. |
