Rhombic dodecahedral and highly edge-and corner-truncated octahedral gold nanocrystal cores with entirely or significant {110} faces were employed to investigate the coreÀshell orientation relationship of AuÀCu 2 O coreÀshell heterostructures. By increasing the volume of reductant added, we synthesized AuÀCu 2 O face-raised cubes, cuboctahedra, and octahedra. TEM characterization indicates a fixed coreÀshell orientation relationship. The {100}, {110}, and {111} facets of the gold cores align parallel to the corresponding faces of the Cu 2 O shells. Structural requirements of the gold cores for the preparation of AuÀCu 2 O stellated icosahedra indicate that icosahedral gold nanocrystals are good candidates. Use of trisoctahedral nanocrystal cores cannot generate stellated icosahedra, but unusual face-raised octahedra with V-shaped {111} edges can be synthesized. CoreÀshell cubes, face-raised cubes, coreÀshell octahedra, and face-raised octahedra were examined for their comparative photocatalytic activity toward the photodegradation of methyl orange. Remarkably, all the cubes were found to be photocatalytically inactive because they are bounded by essentially {100} facets. Face-raised octahedra with more {111} facets showed significantly better photocatalytic performance than regular AuÀCu 2 O coreÀshell octahedra. The results reveal that gold nanocrystal-enhanced photocatalysis can be achieved only with Cu 2 O shells exposing proper facets.

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Free time, Time management, Quality of life, Undergraduates,

Internet addiction has become a significant concern with a variety of negative outcomes among the younger generation in today's modern society and has been investigated and discussed in many studies. Of all the influencing factors, boredom has been proven to be a common trigger for intensive internet use and can result in particularly problematic internet use behavior. A number of studies have indicated the importance of time use as a treatment. Thus, using free time well might serve as a solution to reduce leisure boredom and internet addiction. The current study aims to test a structural model with a sample of university students to investigate the relationships among free-time management, leisure boredom, and internet addiction. The sample consisted of 475 undergraduate students. Data were collected through questionnaires distributed between March 1 and April 30, 2016. Totally, 446 valid questionnaires were received. The structural model was examined after the competent measurement model was processed. Results from the structural model supported that free-time management decreases boredom during leisure time, and boredom during leisure time enhances internet addiction. Furthermore, leisure boredom was revealed to play a role as a distinct mediator between free-time management and internet addiction. Finally, managerial applications and recommendations for future research are suggested based on the research results.

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