In summary, the early stages of the electron emission in water from NDs upon illumination with DUV and VIS light were probed using ultrafast TA spectroscopy. While the emission of solvated electrons was observed for hydrogenated, hydroxylated and carboxylated NDs upon DUV illumination, it was only detected for hydrogenated NDs upon VIS excitation. This is interpreted by synergistic effects between sp 2 -hybridized carbon surface reconstructions, which serve as a pool of electrons to be excited with VIS light, and hydrogenated surface groups offering a local negative electron affinity facilitating electron emission. On the other hand, these FLRs are detrimental for electron emission upon DUV illumination as they behave as trap states increasing electron recombination. These findings may suggest that a mixed ND surface chemistry composed of hydrogenated surface groups for electron emission and visible-light absorbing states -sp 2 -hybridized surface states in this work -should be considered for improving the electron emission properties of NDs and nanostructured diamond under solar excitation.