To confirm UK-5099 combination state between Fe3O4 and PPy, FT-IR and zeta potential techniques were employed to examine surface physics and chemistry of the samples, as shown in Fig. 2 and Fig. 3. In the Fe3O4 spectrum (Fig. 2a), the strong peak at 578 cm−1 corresponds to Fe–O stretching vibration . The broad peak centered around 3410 cm−1 and the other peaks at 1630, 893, and 793 cm−1 arise from the stretching, bending, and deforming vibrations of O–H due to the surface adsorbed water and ethanol . In the Fe3O4/PPy spectrum (Fig. 2b), the peak at 1556 and 1473 cm−1 correspond to CC asymmetric and symmetric ring-stretching vibrations . The peak at 1315 cm−1 is attributed to C–N stretching vibration. The other peaks at 1191, 1095, 1046, 926, 793, 681 cm−1 are due to in-plane and out-of-plane C–H and N–H bending vibrations ,  and . Compared with those in Fig. 2b, the peaks at 1398 and 968 cm−1 in the dedoped Fe3O4/PPy spectrum (Fig. 2c) are greatly reduced in intensity. As a result, the two peaks are related to the doping state of PPy. It is worth noting that the peak corresponding to Fe–O stretching vibration blue-shifts to 614 cm−1 in Fig. 2b and c, indicating strong combination rather than blending of the magnetic and nonmagnetic components.