Here we report a high efficiency photocatalyst, i.e., Mn2+-doped and N-decorated ZnO nanofibers (NFs) enriched with vacancy defects, fabricated via electrospinning and a subsequent controlled annealing process. This nanocatalyst exhibits excellent visible-light photocatalytic activity and an apparent quantum efficiency up to 12.77%, which is 50 times higher than that of pure ZnO. It also demonstrates good stability and durability in repeated photocatalytic degradation experiments. A comprehensive structural analysis shows that high density of oxygen vacancies and nitrogen are introduced into the nanofibers surface. Hence, the significant enhanced visible photocatalytic properties for Mn-ZnO NFs are due to the synergetic effects of both Mn2+ doping and N decorated. Further investigations exhibit that the Mn2+-doping facilitates the formation of N-decorated and surface defects when annealing in N2 atmosphere. N doping induce the huge band gap decrease and thus significantly enhance the absorption of ZnO nanofibers in the range of visible-light. Overall, this paper provides a new approach to fabricate visible-light nanocatalysts using both doping and annealing under anoxic ambient.

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Density functional theory calculations are conducted to investigate the stability and interactions among small helium (He) clusters in bulk tungsten (W). The lowest energy structure of each cluster for sizes n = 1 to 6 is determined. With the formation of He clusters, He defects form in bulk W. The thermodynamics of the clusters are investigated in the temperature range of 1000–2300K using molecular dynamics. This study provides the information essential to understand small He cluster behavior in bulk W.

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The synergistic effect of Li–Ti and K–Ti dopants on the energy, structure and electronic properties of NaAlH4 has been investigated using DFT and AIMD.