Considering the metal oxides calculations, we compared the DFT and DFT+ U on Anatase-TiO2(101) surface. We benchmarked the U values on bulk Anatase-TiO2. On the glycerol species adsorption, we found that with or without U correction the results are almost the same. Thus in our calculation, we used DFT (not +U) to calculate all the adsorption energy on metal oxides surface.