Gelation of the suspensions was done through three different types of freezing. "Hightemperature" freezing of the suspension was performed in a freezer (-12 ℃), while "lowtemperature" freezing was achieved by submerging the suspension in liquid nitrogen (-196 ℃). Two-step freezing was conducted by first freezing the sample at -12 ℃ for 8 hours, allowing the sample to thaw, then re-freezing the sample at liquid nitrogen temperature. An external static magnetic field (SMF) was applied to some gelation processes using permanent magnets. The porous structure of the cryogel was revealed by freeze-drying for 48 hours. Specificities of sample preparation are detailed in Section 2 of Supporting Information.