Manganese　dioxide　(MnO2),　as　a　promising　green　material,　has　recently　attracted　considerable　attention　of　researchers　from　various　fields.　In　this　work,　a　facile　method　was　introduced　to　prepare　binary　hybrids　by　fabricating　three-dimensional　(3D)　zinc　hydroxystannate　(ZHS)　cubes　on　two-dimensional　(2D)　MnO2　nanosheets　towards　excellent　flame　retardancy　and　toxic　effluent　elimination　of　epoxy　(EP)　resin.　Microstructural　analysis　confirmed　that　the　morphologies　and　structures　of　MnO2@ZHS　binary　hybrids　were　well　characterized,　implying　the　successful　synthesis.　Additionally,　the　morphological　characterization　indicated　that　MnO2@ZHS　binary　hybrids　could　achieve　satisfactory　interfacial　interaction　with　the　EP　matrix　and　be　well　dispersed　in　nanocomposites.　Cone　calorimeter　test　suggested　that　MnO2@ZHS　binary　hybrids　effectively　suppressed　the　peak　of　heat　release　rate　and　total　heat　release　of　EP　nanocomposites,　performing　better　than　MnO2　or　ZHS　alone.　Condensed-phase　analysis　revealed　that　MnO2@ZHS　binary　hybrids　could　promote　the　char　density　and　graphitization　degree　of　char　residues　and　thereby　successfully　retard　the　permeation　of　oxygen　and　flammable　gases.　Moreover,　through　the　analysis　of　gas　phase,　it　can　be　concluded　that　MnO2@ZHS　binary　hybrids　could　efficiently　suppress　the　production　of　toxic　gases　during　the　degradation　of　EP　nanocomposites.　This　work　implies　that　the　construction　of　2D/3D　binary　hybrids　with　an　interfacial　interaction　is　an　effective　way　to　fabricate　high-performance　flame　retardants　for　EP.　©　2019　by　the　authors.