Sponge Effect Boosting Oxygen Reduction Reaction at the Interfaces between Mullite SmMn2O5 and Nitrogen-Doped Reduced Graphene Oxide.
Meng YuLi WangJieyu LiuHui LiXiuyao LangChunning ZhaoZhanglian HongWeichao WangPublished in: ACS applied materials & interfaces (2019)
Exploring the effect of interfacial structural properties on catalytic performance of hybrid materials is essential in rationally designing novel electrocatalysts with high stability and activity. Here, in situ growth of mullite SmMn2O5 on nitrogen-doped reduced graphene oxide (SMO@NrGO) is achieved for highly efficient oxygen reduction reaction (ORR). Combining X-ray photoelectron spectroscopy and density functional theory calculations, interfacial chemical interactions between Mn and substrates are verified. Interestingly, as revealed by charge density difference, the interfacial Mn-N(C) bonds display a sponge effect to store and compensate electrons to boost the ORR process. In addition, bidentate adsorption of oxygen intermediates instead of monodentate ones is observed in hybrid materials, which facilitates the interactions between intermediates and active sites. Experimentally, the hybrid catalyst SMO@NrGO exhibits a half-wave potential as high as 0.84 V, being comparable to benchmark Pt/C and higher than that of the pure SMO (0.68 V). The Zn-air battery assembled with SMO@NrGO shows a high discharge peak power density of 244 mW cm-2 and superior cycling stability against noble metals.
Keyphrases
- reduced graphene oxide
- density functional theory
- highly efficient
- gold nanoparticles
- ionic liquid
- molecular dynamics simulations
- molecular dynamics
- electron transfer
- high resolution
- room temperature
- magnetic resonance
- perovskite solar cells
- magnetic resonance imaging
- single molecule
- heavy metals
- climate change
- solid state
- crystal structure
- transition metal