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Understanding the interface-induced effects of heteronanostructured catalysts remains a significant challenge due to their structural complexity, but it is crucial for developing novel applied catalytic materials. This work reports a systematic characterization and catalytic evaluation of MnOxnanoparticle-dispersed CeO2nanocubes for two important industrial applications, namely, diesel soot oxidation and continuous-flow benzylamine oxidation. The X-ray diffraction and Raman studies reveal an unusual lattice expansion in CeO2after the addition of MnOx. This interesting observation is due to conversion of smaller sized Ce4+(0.097 nm) to larger sized Ce3+(0.114 nm) in cerium oxide led by the strong interaction between MnOxand CeO2at their interface. Another striking observation noticed from transmission electron microscopy, high angle annular dark-field scanning transmission electron microscopy, and electron energy loss spectroscopy studies is that the MnOxspecies are well-dispersed along the edges of the CeO2nanocubes. This remarkable decoration leads to an enhanced reducible nature of the cerium oxide at the MnOx/CeO2interface. It was found that MnOx/CeO2heteronanostructures efficiently catalyze soot oxidation at lower temperatures (50% soot conversion, T50∼660 K) compared with that of bare CeO2nanocubes (T50∼723 K). Importantly, the MnOx/CeO2heteronanostructures exhibit a noticeable steady performance in the oxidation of benzylamine with a high selectivity of the dibenzylimine product (∼94–98%) compared with that of CeO2nanocubes (∼69–91%). The existence of a strong synergistic effect at the interface sites between the CeO2and MnOxcomponents is a key factor for outstanding catalytic efficiency of the MnOx/CeO2heteronanostructures.