Mo et al.
[56] observed that H-MnO
2 (hollow spherical γ-MnO
2), γ-MnO
2, α-MnO
2 and β-MnO
2 exhibited modest catalytic activity, achieving toluene
t90 values of 230, 238, 263 and 275 °C, respectively. The incorporation of Pt significantly enhanced the catalytic performance of these catalysts, as shown in
Table 3. However, notable differences were observed among the catalysts due to variations in the strength of the strong metal-support interaction (SMSI) between Pt and different MnO
2 crystal phases. The intensity of SMSI is closely related to the structure of the support. Although low-crystallinity γ-MnO
2 readily promotes the formation of surface oxygen vacancies, its incomplete crystal planes weaken the electronic structure matching between metal particles and the support, thereby hindering effective SMSI. Strong SMSI profoundly improves catalytic activity. For Pt/α-MnO
2 and Pt/β-MnO
2, MnO
2 migration encapsulating Pt nanoparticles-a typical SMSI feature-was observed, whereas no such phenomenon appeared for Pt/γ-MnO
2. Consequently, the
t90 values followed the order Pt/α-MnO
2 (170 °C) > Pt/β-MnO
2 (180 °C) > Pt/γ-MnO
2 (190 °C), consistent with the SMSI strength trend. The morphology and structure of manganese oxides are key factors influencing SMSI strength, and the loading method also affects SMSI. Hu et al.
[57] synthesized Pt/MnO
2-r-WI though deposition in an alkaline medium, resulting in smaller and more uniformly dispersed Pt nanoparticles. In contrast, Pt/MnO
2-r-IW prepared by conventional impregnation exhibited Pt NP agglomeration up to 1.3 nm. The highly dispersed Pt within Pt/MnO
2-r-WI maximized Pt utilization and generated stronger SMSI, thereby reducing toluene
t90 to 224 °C, significantly lower than 250 °C for Pt/MnO
2-r-IW. Other factors also affect the catalytic performance of supported manganese-based catalysts. For example, the specific surface area exerts an important role. Li et al.
[58] employed acid etching to create pores in LaPdMO
3 (LPMO), selectively removing inert La sites and exposing Pd active sites, thereby substantially enhancing interfacial between Pd and MnO
2. As shown in
Figure 9, the acid-etched catalysts increased the specific surface area from 20 to 180 m
2/g, providing abundant active sites and improving mass transfer, thereby reducing the toluene
t90 from 248 to 200 °C. Xia et al.
[59] reported that the nanotubular morphology of α-MnO
2 in 0.91Au
0.48Pd/α-MnO
2 could anchor a large number of noble metal nanoparticles, creating more active sites. Sun et al.
[60] discovered that Pt/Mn
3O
4-R exhibited superior catalytic performance compared with Pt/Mn
3O
4-C, attributable to the specific surface area of Mn
3O
4-R (138.2 m
2/g) was over ten times that of Mn
3O
4-C (11.7 m
2/g), thereby providing richer anchoring sites for Pt, better dispersion, and facilitating the formation of more Mn−O bonds. To further investigate the construction of active sites in supported manganese-based catalysts, Pan et al.
[61] synthesized Pt/Mn
2O
3. As shown in
Figure 10, Pt embedded within the Mn
2O
3 surface induced lattice distorted, thereby weakening the Mn−O bonds and generating oxygen vacancies though dissociative oxygen activation. In contrast, Pt
0 supported on Al
2O
3 participates in toluene catalytic combustion through adsorbed oxygen species (O
ads), indicating that the support properties influence the VOC reaction mechanism. At high temperatures, acetone can adsorb on Pt sites in Pt/Al
2O
3, thereby deactivating reaction sites; consequently, Pt/Al
2O
3 shows excellent catalytic performance only for toluene, with
t90 values of 199 and 233 °C for toluene and acetone, respectively. Pt/Mn
2O
3, however, avoids deactivation and achieves efficient catalytic combustion of multiple VOC types, with
t90 values of 201 and 169 °C.