Atomically And Electronically Coupled Pt And CoO Hybrid Nanocatalysts For Enhanced Electrocatalytic Performance

Currently,platinum?Pt?is still the most efficient and stable electrocatalyst.Nonetheless,the rational design and fabrication of Pt catalysts remain significant challenges.Recent studies highlight the strong metal support interaction?SMSI?effect between Pt and metal oxides can effectively tune the electronic structure of Pt,which improves the utilization efficiency and long-term durability of Pt.However,the precise control of atomic and electronic structures between Pt and metal oxides is not yet implemented.?i?Here we fabricated size-controlled SC CoO NRs directly on carbon fiber paper?CFP?substrate using cation exchange in gas phase.Atomic-level characterizations in combination with simulations unambiguously reveal that the surface of as-engineered SC CoO NRs is enclosed with textured nano-pyramids,which dominantly exposed{111}facets.?ii?We report,for the first time,Pt NPs was deposited on the surface of pyramidal nanofacets enclosed SC CoO NRs by magnetron sputtering method.The particle size and loading mass of Pt NPs can be well tuned by precisely controlling the sputtering time and current of Pt.Moreover,the high-resolution transmission electron microscopy?HRTEM?image shows that the perfect atomic coupling between Pt NPs and SC CoO NRs assures the epitaxial growth of Pt NPs intimately on the pyramidal nanofacets of SC CoO NRs,thus imposing Pt NPs to dominantly expose active{111}nano-facets.Based on experimental observations and theoretical calculations,we demonstrate that strong electronic interaction between Pt NPs and SC CoO NRs directly lead to favorable down-shifting d-band center of Pt,which is highly preferable for catalytic ORR reactions.As a result,such Pt NPs/SC CoO NRs hybrid catalysts exhibit a substantially enhanced ORR activity and durability in comparison to the Pt benchmark.New hybrid catalysts can achieve a 3.1-fold enhancement in both the kinetic current density and the mass activity in comparison to the state-of-the-art Pt/C catalyst.?iii?This specifically designed hybrid catalyst can be easily integrated into Zn-air batteries.As a result,the Pt/CoO-CoO pair-based battery exhibits better charge and discharge property relative to Pt-RuO₂ pair-based battery.