Tribological Properties of Nano-ZnO/TiO2 Composite Lubricant and functional Transformation from Lubricant to photocatalyst

Abstract In order to improve the wear and emission of engine internal parts, ZnO/TiO2 composites were selected as lubricating oil additives in this study. Firstly, the effects of different amounts of ZnO/TiO2 composites on the friction and wear properties under the same working conditions were investigated on a four-ball friction and wear tester. Secondly, the photocatalytic performance was tested by 722 visible spectrophotometer. The results show that the addition of different amounts of ZnO/TiO2 composite additives can significantly improve the anti-friction and anti-wear properties and photocatalytic properties of lubricating oil, and the effect is the best when the addition amount is 0.5%. Compared with the condition without additives, the friction coefficient is reduced by about 52%, and the wear loss is reduced by about 60. The degradation rate of methyl orange was also increased by about 12%. The test shows that ZnO/TiO2 as lubricating oil additive has good friction reduction performance and photocatalytic performance. It can not only reduce the loss of internal parts of the engine, but also use its photocatalytic performance to catalyze the gas generated by the engine, so as to increase the engine life and achieve green development.