Guided by oxidation-reduction reactions, we in-situ grew MnO2 coating on three novel 3D structured foams, Ni, Fe and Fe75Ni25 (written as MN, MF and MFN) for diesel soot elimination. Systematic characterizations including SEM, HRSTEM-EDS, XRD, Raman spectroscopy, FT-IR, XPS, H-2-TPR and soot-TPR revealed that the substrates affected greatly the morphology, content, structure, surface and redox ability of MnO2 coatings. MnO2 of MN was thin nanoflake, but became thicker on MF and partly turned into nanowire on MFN. The contents of K stabilizer in MnO2 coatings are in proportion to the concentrations of Fe3+ and Ni3+ dopants. MF showed the best pristine activity owing to abundant surface oxygen species, bulk K+, and high-valence manganese. But MF deactivated seriously in 6% H2O (T-50 increased by similar to 30 degrees C) because of excessive hydrophily and K+ loss. MN and MFN displayed splendid reusability; especially 90% of soot loaded on MFN could be removed within 1500s at 420 degrees C in a simulated diesel exhaust. Ni3+ could effectively stabilize K+ and tune surface hydrophily. The used catalysts displayed good adherence against exfoliation. Further, the excellent heat conductivity of metal foams and low coating weights would eliminate hot spots from soot combustion.