The as-fabricated carbon monolith can support quasi-spherical water droplets on its surface (the inset in Fig. 6a). Benefited from the micro/nano-scale structure, the carbon monolith dramatically increases the surface roughness, which is close to the surface structure of a lotus leaf, therefore possessing hydrophobic property [22]. It is well-known that the pyrolysis temperature has a great influence on the resultant carbon monoliths [17].The water contact angles of carbon monoliths are in the range of 108.6–130.0, increasing with the rising pyrolysis temperature (Fig. 6a). These differences in the wettability of carbon monoliths pyrolyzed at different temperatures can also be explained by FT-IR spectroscopy analysis (Fig. 6b). The FT-IR spectrum of C-350 sample shows several peaks of hydrophilic functional groups, such as C@O, CAO, and AOH, while C-600 sample reveals relatively weak hydrophilic peaks. For C-1000 sample, no functional groups are observed. As a result, C-1000 sample has the largestwater contact angle, whichmeans the highest hydrophobicity.