35 research outputs found

    3D‐Printed Metal–Organic Framework‐Derived Composites for Enhanced Photocatalytic Hydrogen Generation

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    This is the final version. Available on open access from Wiley via the DOI in this recordData Availability Statement: Research data are not shared.Direct ink writing technique is used to 3D print Ti-metal–organic framework (MOF) NH2-MIL-125 mixed with boehmite dispersal. Pt is also deposited onto 3D-printed monolith using atomic layer deposition (ALD) to offer additional catalytic sites. The Ti-MOF-derived powder sample and the pyrolyzed 3D-printed monolith samples are evaluated for photocatalytic H2 evolution under UV–vis light. As a proof of concept, herein, it is demonstrated that 3D-printed MOF-derived monolith photocatalysts show five times higher H2 evolution performance compared with TiO2/C powder sample due to better interaction between 3D-printed photocatalysts and the incident light. The high surface area, the formation of hierarchical macro- to nanopores, and the optimizable shape/size of the 3D-printed catalyst maximize the exposure of catalytic active sites to incident photons and increase their photocatalytic H2 evolution performance. In addition, the N-functionalized porous carbon from organic linker, and the uniformly distributed Pt/PtOx species deposited by ALD, provide cocatalytic active sites for photocatalytic reaction and further enhance photocatalytic activity 30% of 3D-printed monoliths. This work on the 3D-printed MOF-derived free-standing monoliths for photocatalytic application provides a readily available approach to further fabricate a variety of 3D-printed MOF-based and derived materials for different energy and environment applications

    Entrepreneurial role models, fear of failure, and institutional approval of entrepreneurship: A tale of two regions

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    Studies on the influence of entrepreneurial role models (peers) on the decision to start a firm ar-gue that entrepreneurial role models in the local environment (1) provide opportunities to learn about entrepreneurial tasks and capabilities, and (2) signal that entrepreneurship is a favorable career option thereby reducing uncertainty that potential entrepreneurs face. However, these studies remain silent about the role of institutional context for these mechanisms. Applying an ex-tended sender-receiver model, we hypothesize that observing entrepreneurs reduces fear of fail-ure in others in environments where approval of entrepreneurship is high while this effect is signif-icantly weaker in low approval environments. Taking advantage of the natural experiment from recent German history and using data from the Global Entrepreneurship Monitor Project (GEM), we find considerable support for our hypotheses

    Avalanche fatalities in the European Alps: long-term trends and statistics

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    Avalanche accidents, particularly those resulting in fatalities, attract substantial attention from policy makers and organizations, as well as from the media and the public. Placing fatal accidents in a wider context requires long-term and robust statistics. However, avalanche accident statistics, like most other accident statistics, often rely on relatively small sample sizes, with single multi-fatality events and random effects having a potentially large influence on summary and trend statistics. Additionally, trend interpretation is challenging because statistics are generally explored at a national level, and studies vary in both the period covered and the methods. Here, we addressed these issues by combining the avalanche fatality data from the European Alps (Austria, France, Germany, Liechtenstein, Italy, Slovenia, and Switzerland) for three different periods between 1937 and 2015 and applying the same data analysis methodology. During the last four decades, about 100 people lost their lives each year in the Alps. Despite considerable inter-annual variation, this number has remained relatively constant in the last decades. However, exploring fatality numbers by the location of the victims at the time of the avalanche revealed two partly opposing trends. The number of fatalities in controlled terrain (settlements and transportation corridors) has decreased significantly since the 1970s. In contrast to this development, the number of fatalities in uncontrolled terrain (mostly recreational accidents) almost doubled between the 1960s and 1980s and has remained relatively stable since then, despite a strong increase in the number of winter backcountry recreationists. Corresponding to these trends, the proportion of fatalities in uncontrolled terrain increased from 72 to 97 %. These long-term trends were evident in most national statistics. Further, the temporal correlation between subsets of the Alpine fatality data, and between some of the national statistics, suggests that time series covering a longer period may be used as an indicator for missing years in shorter-duration datasets. Finally, statistics from countries with very few incidents should be compared to, or analysed together with, those from neighbouring countries exhibiting similar economical and structural developments and characteristics
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