The ruin as memorial - the memorial as ruin

The ruin allows for a visualization of different forms of mourning: we mourn loss, death, decay and destruction; man-made and natural catastrophes; humanity’s futile and successful attempts to master nature; and nature’s indifference to humans and their cruelty against one another. But do we need to conceive memorial ruins differently, depending on whether they commemorate gradual decay and mortality, a natural catastrophe, or various types of governmental, military or economic violence? Could the aesthetic of the ruin dangerously confuse very different forms of terror, violence and violation, directed against other nations, political opponents or ethnic minorities, perhaps even rendering invisible human agency and erasing the specificities of the historical context? Or may the ruin help us to discern where these structures and practices of violence converge? These and related questions are explored in this article

Nanocrystal bilayer for tandem catalysis

Supported catalysts are widely used in industry and can be optimized by tuning the composition and interface of the metal nanoparticles and oxide supports. Rational design of metal-metal oxide interfaces in nanostructured catalysts is critical to achieve better reaction activities and selectivities. We introduce here a new class of nanocrystal tandem catalysts that have multiple metal-metal oxide interfaces for the catalysis of sequential reactions. We utilized a nanocrystal bilayer structure formed by assembling platinum and cerium oxide nanocube monolayers of less than 10 nm on a silica substrate. The two distinct metal-metal oxide interfaces, CeO2-Pt and Pt-SiO2, can be used to catalyse two distinct sequential reactions. The CeO2-Pt interface catalysed methanol decomposition to produce CO and H2, which were subsequently used for ethylene hydroformylation catalysed by the nearby Pt-SiO2 interface. Consequently, propanal was produced selectively from methanol and ethylene on the nanocrystal bilayer tandem catalyst. This new concept of nanocrystal tandem catalysis represents a powerful approach towards designing high-performance, multifunctional nanostructured catalyst