Rolling friction performance and functional conversion from lubrication to photocatalysis of hollow spherical nano-MoS2/nano-TiO2

The rolling friction performance of hollow spherical nano-MoS2/nano-TiO2 (HSMT), as well as the conversion from lubricant to photocatalyst, was studied. By combining the strengths of nano-MoS2 and nano-TiO2, HSMT could not only effectively roll with the rolling friction pair but also form a lubricating film to reduce friction and wear. The increase in HSMT photocatalytic activity was ascribed to three reasons. First was the exfoliation of nano-MoS2 into nanosheets. Second was the synergistic catalysis between nanosheets and nano-TiO2. Third was the good lubrication of nano-MoS2, which protected nano-TiO2 against acute friction and loss of crystal structure. The findings provide a possible approach for designing a novel green lubricant that may be re-used as a photocatalyst after lubricating service life.