7 and 877.5 eV) with the fitting ratio of 41.7% and 52.3%, respectively. Figure 4 ESCA/XPS spectrum of (a) survey scan and (b) Ni 2p in the Ni-NiO/PDDA-G nanohybrids. The electrochemical investigation

of Ni-NiO/PDDA-G was applied in the 0.5 M aqueous H2SO4 (shown in Figure 5a), 0.5 M aqueous H2SO4 + 0.5 M CH3OH (shown in Figure 5b), and the O2-saturated 0.5 M aqueous H2SO4 (shown in Figure 5c). Figure 5c shows no significant difference, as evidenced by the blue line denoting the O2-saturated ORR first scan and the green line denoting the tenth scan. The inset in Figure 5c is the ORR test Hormones inhibitor in the N2-saturated 0.5 M aqueous H2SO4. The O2-saturated ORR test current density at the −0.2 to 0.2 V vs. Ag/AgCl is about 25 times than that of the N2-saturated ORR test of Ni-NiO/PDDA-G. Furthermore, the O2-saturated ORR test current density at the 1.0 to 1.2 V vs. Ag/AgCl is about 5 times than that of the N2-saturated ORR test of Ni-NiO/PDDA-G. The electrochemical

impedance spectroscopy result for testing the 0.5 M aqueous H2SO4 and 0.5 M aqueous H2SO4 + 0.5 M CH3OH is shown in Figure 5d. The semicircle curve of Ni-NiO/PDDA-G in the 0.5 M aqueous H2SO4 is higher than that in the 0.5 M aqueous H2SO4 + 0.5 M CH3OH, showing the higher chemical reaction ability. Thus, the Ni-NiO/PDDA-G is more suitable for ORR than for the methanol oxygen reaction. Figure 5 The electrochemical studies of Ni-NiO/PDDA-G nanohybrids. (a) CV in the 0.5 M aqueous H2SO4, (b) CV in the 0.5 M aqueous H2SO4 + 0.5 M CH3OH, (c) ORR test in the O2-saturated 0.5 M aqueous H2SO4, and (d) the EIS spectrum at −0.3 V. Conclusions We have successfully synthesized selleck chemicals llc the Ni-NiO/PDDA-G nanohybrids,

and the size of Ni-NiO nanoparticles was about 2 to 5 nm. The morphologies and chemical composition of Ni-NiO/PDDA-G were evaluated by TGA, XRD, TEM, and ESCA/XPS. The results show the phase of the Ni-NiO/PDDA-G, and the loading content of Ni-NiO is about 35 wt%. The CV and EIS results of Ni-NiO/PDDA-G in 0.5 M aqueous H2SO4 are better than those in 0.5 M aqueous H2SO4 + 0.5 M CH3OH. Therefore, Ni-NiO/PDDA-G in 0.5 M Smoothened aqueous H2SO4 is more suitable as ORR electrocatalyst and could be a candidate of for cathode electrocatalyst of fuel cells. Authors’ information TYY is an selleck screening library assistant engineer at the Institute of Nuclear Energy Research. LYH is a postdoctoral fellow at National Taiwan University of Science and Technology. PTC is a postdoctoral fellow at National Taiwan University. CYC is an associate professor at National Taiwan University. TYC and KSW are undergraduate students at Ming Chi University of Technology. TYL holds an assistant professor position at Ming Chi University of Technology. LKL is a research fellow at Academia Sinica and an adjunct professor at National Taiwan University.