Efficient removal of H2S from industrial emissions and the environment is crucial for safeguarding human health and ecosystems. Conventional metal oxide-based materials for H2S sequestration trap sulfur species in solid matrices but suffer from low uptake capacity (<65 mgH2S g-1) and require elevated operating conditions due to limited active sites and kinetic barriers. Herein, we achieve efficient H2S sequestration under ambient conditions by chemically activating metal oxide surfaces using reticular chemistry to enhance solid-gas reactions. This approach integrates a metal oxide core with a metal-organic framework (MOF) layer, forming a surface-activated interfacial nanoreactor (SAIN). The MOF facilitates H2S transfer to the functional interface while activating the metal oxide surface for enhanced reactivity. SAIN achieves a higher H2S sequestration of up to 1524 mgH2S g-1 across a wide concentration range with nearly 100% efficiency. It demonstrates a >23-fold improvement over standalone metal oxide and/or MOF platforms, higher than emerging materials by up to 508-fold in H2S uptake and 24-fold in sequestration rate. Mechanistic studies reveal that interfacial electron migration and electronic hybridization weaken metal-oxygen bonds, enhancing their interactions with H2S and promoting efficient reactive sequestration. Our "activate-react-lock" strategy offers valuable insights for designing functional interfaces to activate nanomaterial surfaces for diverse environmental, chemical, and energy applications.