Fabrication of C@Mo_xTi_1−xO_2−Δ nanocrystalline with functionalized interface as efficient and robust PtRu catalyst support for methanol electrooxidation

A core shell structured C@Mo_xTi_1-xO_2-δ nanocrystal with a functionalized interface (C@MTNC-FI) was fabricated via the hydrothermal method with subsequent annealing derived from tetrabutyl orthotitanate. The formation of anatase TiO₂ was inhibited by the simultaneous presence of the hydrothermal etching/regrowth process, infiltration of Mo dopants and carbon coating, which endows the C@MTNC-FI with an ultrafine crystalline architecture that has a Mo-functionalized interface and carbon-coated shell. PtRu nanoparticles (NPs) were supported on C@MTNC-FI by employing a microwave-assisted polyol process (MAPP). The obtained PtRu/C@MTNC-FI catalyst has 2.68 times higher mass activity towards methanol electrooxidation than that of the un-functionalized catalyst (PtRu/C@TNC) and 1.65 times higher mass activity than that of PtRu/C catalyst with over 25% increase in durability. The improved catalytic performance is due to several aspects including ultrafine crystals of TiO₂ with abundant grain boundaries, Mo-functionalized interface with enhanced electron interactions, and core shell architecture with excellent electrical transport properties. This work suggests the potential application of an interface-functionalized crystalline material as a sustainable and clean energy solution.