## 3 Results  
Figure 1 represents powder X-ray diffraction patterns of GR with SO\({}_{4}\)\({}^{2-}\) or with conducting polymer (PEDOT). The diffractogram of GR-SO\({}_{4}\), sulfate intercalated green rust showed well developed (00l) diffraction below 20 of 30\({}^{\circ}\) and several small lattice peaks above 20 of 30\({}^{\circ}\). Similarly, the diffractogram of GR-PEDOT showed (00l) peaks and lattice peaks, respectively. The d-spacings of both GRs calculated by (003) peak was 0.84 and 1.08 nm, respectively, showing correspondence with the molecular dimension of SO\({}_{4}\)\({}^{2-}\) and PEDOT:PSS, respectively. It is notable that the GR-PEDOT showed a larger number of repeated (00l) peaks with higher intensity than GR-SO\({}_{4}\), which would be attributed to the different crystallinity of GR in the presence of the polymer. The crystallite sizes calculated by [PERSON]'s equation [16] utilizing (003) peaks were 7.36 and 10.5 nm for GR-SO\({}_{4}\) and GR-PEDOT, respectively. The (hkl) indexing followed the crystal phase of hydrodtalcite (JCPDS NO.14-0191) as previously reported for green rust [17]. The surface charge of both GRs were evaluated by measuring its zeta potential in deionized water (Figure 2). The zeta potential of GR-SO\({}_{4}\) lay in the range of \(-\)10 mV to 30 mV, whereas that of GR-PEDOT was located between \(-\)40 mV and 0 mV. The full widths at half maximum of both samples were similarly narrow (~21 mV). The average zeta potential of GR-SO\({}_{4}\) and GR-PEDOT was 6.87 \(\pm\) 0.44 mV and \(-\)19.8 \(\pm\) 0.52 mV, respectively, clearly showing respective positive and negative surface charge. Sanning electron microscopy for both samples was carried out in order to observe particle size, morphology and homogeneity in phase (Figure 3). The image for GR-SO\({}_{4}\) showed relatively small particles with a size of 60 nm with some agglomeration. On the other hand, the particle of GR-PEDOT is larger and more plate-like than GR-SO\({}_{4}\). The average particle size of GR-PEDOT was 140 nm and it also showed some agglomerations. In the SEM image of GR-PEDOT, we could not observe any serious aggregation of particles or lumps of polymers, indicating the PEDOT:PSS was well hybridized with the GR lattice without phase segregation. Energy-dispersive spectroscopy (EDS) mapping images showed the location of GR framework was overlapped with those of counter-anions. The locations of S, Fe, O (Fe, O from GR; S, O from SO\({}_{4}\)\({}^{2-}\)) were well-overlapped in GR-SO\({}_{4}\); the locations of C, S, Fe, O (Fe, O from GR; C, S, O from PEDOT:PSS) were also well-overlapped in GR-PEDOT (Figures S1 and S2). The photographic images of both GRs displayed in Figure 3 showed fine powdery state with greenish brown or black color, indicating the existence of Fe\({}^{2+}\)/Fe\({}^{3+}\) (for both samples) and PEDOT:PSS (in GR-PEDOT) in the powders. Figure 1: X-ray diffraction (XRD) patterns and corresponding schematic interlayer diagrams for (**a**) GR-SO\({}_{4}\) and (**b**) GR-PEDOT. Figure 2: Zeta-potential graphs of (**a**) GR-SO\({}_{4}\) and (**b**) GR-PEDOT. Figure 4A showed XANES for GR-SO\({}_{4}\) and GR-PEDOT. Both spectra were similar in terms of peak shape and intensity. In particular, the pre-edge at 7114.04 eV and main edge at 7128.27 eV were commonly observed for both samples. The EXAFS in R-space was shown in Figure 4B. There could be observed a strong first shell peak at 1.4 A (non-phase-shift corrected) and a relatively small second shell peak at 2.6 A (non-phase-shift corrected), attributed to Fe-O and Fe-Fe bonds, respectively. The peak positions and shapes corresponded well to the EXAFS spectra of previously reported green rust [18; 19]. The oxygen-scavenging effect of GRs depending on different interlayer anions were evaluated in time-course (Figure 5). The test was carried out under ambient composition of air where ~20% of oxygen existed.