Grasping pros and cons of SiO2 proximal to Lewis acidic metal cations in activating H2O2 heterolysis under electric environments

Minsung Kim, Heejin Noh, Jung Hyun Lee, Taekyung Yu, Jongsik Kim

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Lewis acidic metals (Mδ+) cleave H2O2 to evolve OH used for fragmenting aqueous wastes. Mδ+ species are situated near SiO2 and generate interfacial Mδ+-SiO2 domains, where Mδ+ species can avoid aggregation, retain OH productivity with minimal leaching via chelation to the –OH of SiO2, elevate the collisions between Mδ+ and H2O2 or between OH and aqueous pollutants via confinement, and destabilize contaminants via electron (e-) transfer. The merits of SiO2 stated earlier, however, remain abstract and only partially clarified. Herein, interfacial Niδ+-SiO2 domains were created on SiO2-modified NiS/Ni9S8 (NiS/Ni9S8-SiO2) to elaborate the aforementioned advantages of SiO2 under electric conditions, where it was hypothesized that e- transfer can occur from O2–/di-sulfide (S22-)/poly-sulfide (SN2-) to Niδ+ species. SiO2 was verified to increase the amount of Niδ+ speices for NiS/Ni9S8-SiO2 and reduce their Lewis acidic strengths, which was conducive to lowering the energy barrier required for H2O2 dissection. SiO2 was demonstrated to hardly promote the collisions of Niδ+ with H2O2 because of the hydrogen bonding of H2O2 with SiO2, reduce Niδ+ leaching via e- acceptance from O2–/S22-/SN2- rather than via –OH chelation, while making e- migration from Niδ+ to aqueous organics scarcely compelling.

Original languageEnglish
Article number157557
JournalApplied Surface Science
Publication statusPublished - 2023 Sept 15

Bibliographical note

Publisher Copyright:
© 2023 Elsevier B.V.


  • Encapsulation
  • HO dissection
  • Metal leaching
  • Metal sulfide
  • OH
  • Silica

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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