Unique Facet Effects of Metastable Pt/TiO₂ Catalysts in Water Activation for VOCs Degradation

The treatment of industrial-sourced VOCs (Volatile Organic Compounds) stands as a pivotal research topic within the realm of environmental catalysis. The intricate composition of VOCs, especially the presence of H₂O, frequently undermines the catalysts in the treatment systems. In this study, we have explored metastable catalysts that are regulated by different facets, which can activate H₂O into active oxygen species required for the reaction. Surprisingly, the sample with the {101} facet exposed demonstrates superior performance compared to the sample with the high-energy {001} facet with H₂O. In fact, the metastable structures constructed from diverse atomic arrangements are the key to breaking through this conventional understanding. Although the emergence of ¹⁸OCO¹⁸ indicates that all samples can achieve the H₂O process, the Pt/TiO₂-MS {101} sample, with its longer M-O bonds and more Pt-O_meta-Ti, exhibits lower H₂O dissociation energy and stronger lattice oxygen mobility. In contrast, the high-energy facets and the increased Pt⁰ endow the Pt/TiO₂-MS {001} sample with a stronger ability to activate O₂. The distinct catalytic behaviors displayed by the metastable structures with different facets exposed offer fresh strategies for designing highly efficient catalysts.