In the present work, nanowire morphologies of α-MnO, cobalt monodoped α-MnO, Cu and Co bidoped α-MnO, and Ni and Co bidoped α-MnO samples were prepared by a facile hydrothermal synthesis. The structural, morphological, surface, and redox properties of all the as-prepared samples were investigated by various characterization techniques, namely, scanning electron microscopy (SEM), transmission and high resolution electron microscopy (TEM and HR-TEM), powder X-ray diffraction (XRD), N sorption surface area measurements, X-ray photoelectron spectroscopy (XPS), hydrogen-temperature-programmed reduction (H-TPR), and oxygen-temperature-programmed desorption (O-TPD). The soot oxidation performance was found to be significantly improved via metal mono- and bidoping. In particular, Cu and Co bidoped α-MnO nanowires showed a remarkable improvement in soot oxidation performance, with its T (50% soot conversion) values of 279 and 431 °C under tight and loose contact conditions, respectively. The soot combustion activation energy for the Cu and Co bidoped MnO nanowires is 121 kJ/mol. The increased oxygen vacancies, greater number of active sites, facile redox behavior, and strong synergistic interaction were the key factors for the excellent catalytic activity. The longevity of Cu and Co bidoped α-MnO nanowires was analyzed, and it was found that the Cu/Co bidoped α-MnO nanowires were highly stable after five successive cycles and showed an insignificant decrease in soot oxidation activity. Furthermore, the HR-TEM analysis of a spent catalyst after five cycles indicated that the (310) crystal plane of α-MnO interacts with the soot particles; therefore, we can assume that more-reactive exposed surfaces positively affect the reaction of soot oxidation. Thus, the Cu and Co bidoped α-MnO nanowires provide promise as a highly effective alternative to precious metal based automotive catalysts.

The incorporation of high-aspect-ratio nanostructures across surfaces has been widely reported to impart antibacterial characteristics to a substratum. This occurs because the presence of such nanostructures can induce the mechanical rupture of attaching bacteria, causing cell death. As such, the development of highefficacy antibacterial nano-architectures fabricated on a variety of biologically relevant materials is critical to the wider acceptance of this technology. In this study, we report the antibacterial behavior of a series of substrata containing multi-directional electrodeposited gold (Au) nanospikes, as both a function of deposition time and precursor concentration. Firstly, the bactericidal efficacy of substrata containing Au nanospikes was assessed as a function of deposition time to elucidate the nanopattern that exhibited the greatest degree of biocidal activity. Here, it was established that multi-directional nanospikes with an average height of $302 nm AE 57 nm (formed after a deposition time of 540 s) exhibited the greatest level of biocidal activity, with $88% AE 8% of the bacterial cells being inactivated. The deposition time was then kept constant, while the concentration of the HAuCl 4 and Pb(CH 3 COO) 2 precursor materials (used for the formation of the Au nanospikes) was varied, resulting in differing nanospike architectures.Altering the Pb(CH 3 COO) 2 precursor concentration produced multi-directional nanostructures with a wider distribution of heights, which increased the average antibacterial efficacy against both Gramnegative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus bacteria. Importantly, the in situ electrochemical fabrication method used in this work is robust and straightforward, and is able to produce highly reproducible antibacterial surfaces. The results of this research will assist in the wider utilization of mechano-responsive nano-architectures for antimicrobial surface technologies.

Surface defects of Fe-doped CeO2 nanorods were found to be active sites for increasing peroxidase mimetic activity.

Transition metal doped ceria nanorods exhibit a better CO oxidation activity at lower temperatures.