Thomas Risse

Storing energy in molecular form, particularly hydrogen in carbon‐free carriers such as ammonia, is considered a key strategy for future energy systems. The release of hydrogen via ammonia decomposition is a critical step in this context that requires scalable and economically viable catalysts. In this work, spray‐flame synthesis (SFS) was employed to prepare La _{1– x} Sr _x CoO _{3− δ} (0≤ x ≤ 1) nanoparticles (≈ 10 nm), which serve as precursors for SrO‐promoted Co/La ₂ O ₃ catalysts prepared by exsolution. ESR, operando XRD, and ambient pressure photoelectron spectroscopy (APXPS) provide insights into dynamic interfacial restructuring of the catalysts under the harsh ammonia decomposition conditions. The catalysts contain 25 wt% Co and achieve a maximum hydrogen productivity of 108 ·g _Co ⁻¹ ·min ⁻¹ at 500°C for the La _0.75 Sr _0.25 CoO _{3− δ} ‐derived material. The coverage of La ₂ O ₃ with SrO/Sr─OH species under reaction conditions inhibits the migration of La‐based species, which block active Co sites in the absence of the promoter. An excess of Sr, however, promotes the growth of Co particles and reduces the exposed Co surface area. Beyond its structural role, operando APXPS reveals that SrO also influences reaction kinetics by facilitating NH _x decomposition and weakening the binding strength of nitrogen, which is consistent with an electrostatic effect of SrO.

Storing energy in molecular form, particularly hydrogen in carbon‐free carriers such as ammonia, is considered a key strategy for future energy systems. The release of hydrogen via ammonia decomposition is a critical step in this context that requires scalable and economically viable catalysts. In this work, spray‐flame synthesis (SFS) was employed to prepare La _{1– x} Sr _x CoO _{3− δ} (0≤ x ≤ 1) nanoparticles (≈ 10 nm), which serve as precursors for SrO‐promoted Co/La ₂ O ₃ catalysts prepared by exsolution. ESR, operando XRD, and ambient pressure photoelectron spectroscopy (APXPS) provide insights into dynamic interfacial restructuring of the catalysts under the harsh ammonia decomposition conditions. The catalysts contain 25 wt% Co and achieve a maximum hydrogen productivity of 108 ·g _Co ⁻¹ ·min ⁻¹ at 500°C for the La _0.75 Sr _0.25 CoO _{3− δ} ‐derived material. The coverage of La ₂ O ₃ with SrO/Sr─OH species under reaction conditions inhibits the migration of La‐based species, which block active Co sites in the absence of the promoter. An excess of Sr, however, promotes the growth of Co particles and reduces the exposed Co surface area. Beyond its structural role, operando APXPS reveals that SrO also influences reaction kinetics by facilitating NH _x decomposition and weakening the binding strength of nitrogen, which is consistent with an electrostatic effect of SrO.

In this article we shed light on newly emerging perspectives to characterize and understand the interplay of diffusive mass transport and surface catalytic processes in pores of gas phase metal catalysts. As a case study, nanoporous gold, as an interesting example exhibiting a well-defined pore structure and a high activity for total and partial oxidation reactions is considered. PFG NMR (pulsed field gradient nuclear magnetic resonance) measurements allowed here for a quantitative evaluation of gas diffusivities within the material. STEM (scanning transmission electron microscopy) tomography furthermore provided additional insight into the structural details of the pore system, helping to judge which of its features are most decisive for slowing down mass transport. Based on the quantitative knowledge about the diffusion coefficients inside a porous catalyst, it becomes possible to disentangle mass transport contributions form the measured reaction kinetics and to determine the kinetic rate constant of the underlying catalytic surface reaction. In addition, predictions can be made for an improved effectiveness of the catalyst, i.e., optimized conversion rates. This approach will be discussed at the example of low-temperature CO oxidation, efficiently catalysed by npAu at 30 °C. The case study shall reveal that novel porous materials exhibiting well-defined micro- and mesoscopic features and sufficient catalytic activity, in combination with modern techniques to evaluate diffusive transport, offer interesting new opportunities for an integral understanding of catalytic processes. Graphical Abstract

This article contributes to two debates about international relations (IR) as a discipline: first, how global is IR, and how is it structured? Second, what is the state of theory in IR? We conducted (co-) citation analyses of both Web of Science (WoS) and—for the first time— non-WoS publications from Europe, North America, Latin America, Africa, and Asia. With regard to the first question, we find that global IR resembles a core–periphery structure as a “hub and spoke” system whereby transatlantic core nodes are interconnected to each other and to some periphery nodes, while the periphery nodes are connected to the core but not to each other. IR scholarship in the periphery quotes the transatlantic theory cluster but is not linked to each other, not even in the same region. Knowledge produced in the periphery has to go through the transatlantic core in order to be recognized globally. As to the transatlantic core, we identify two major (co-) citation clusters: one committed to IR theory-building across issue areas from a variety of perspectives and the other focused on security studies with a strong emphasis on quantitative methods. With regard to the second question, global IR hangs together through references to the IR theory cluster consisting of North American and European authors who appear to define what IR theory is. Scholars in the periphery refer to this transatlantic IR theory cluster when engaging in theory-building. IR theories have become rather diverse and pluralistic, even in the core. While scholars still refer to the big “isms,” they use them around the globe in a synthesizing manner.

The EU is surrounded by areas of limited statehood (ALS) and contested orders (CO) in its southern and eastern neighbourhood. Resilience has become a focus of attention in the academic debate on how to successfully deal with ALS and CO. Moreover, resilience-building is a new cornerstone in the EU’s foreign and security policy. However, to what extent is resilience a mechanism to cope with ALS and CO? What are the sources of resilience? To what extent does the EU act as a resilience builder or spoiler in its neighbourhood? By presenting a new conceptual framework for analysing the interplay between risks, resilience, and governance breakdown/violent conflict as well as through in-depth empirical evidence, this special issue puts forward three key arguments. First, resilience is a key mechanism to prevent governance breakdown and violent conflict in the EU’s neighbourhood. Second, three sources are key in building resilience: Social trust within societies and communities, legitimacy of (state and non-state) governance actors and institutions, as well as effective, fair, and inclusive governance institutions. Third, if external actors, such as the EU, seek to build resilience, they need to factor in long-time horizons, in-depth local knowledge, and a clearly designed strategy.

AsInternational Organizationcommemorates its seventy-fifth anniversary, the Liberal International Order (LIO) that authors in this journal have long analyzed is under challenge, perhaps as never before. The articles in this issue explore the nature of these challenges by examining how the Westphalian order and the LIO have co-constituted one another over time; how both political and economic dynamics internal to the LIO threaten its core aspects; and how external threats combine with these internal dynamics to render the LIO more fragile than ever before. This introduction begins by defining and clarifying what is “liberal,” “international,” and “orderly” about the LIO. It then discusses some central challenges to the LIO, illustrated by the contributors to this issue as well as other sources. Finally, we reflect on the analytical lessons we have learned—or should learn—as the study of the LIO, represented by scholarship inInternational Organization, has sometimes overlooked or marginalized dynamics that now appear central to the functioning, and dysfunction, of the order itself.

Areas of limited statehood where central government authorities lack the capacity of implementing and enforcing decisions and/or lack the monopoly over the means of violence, are ubiquitous. However, these areas are neither ungovernable nor ungoverned. Enormous variation exists, that includes badly governed places but also “good governance” in areas of limited statehood, sometimes separated only by a few blocks. Effective governance (public service provision, rule-making) depends on three factors: legitimacy; social trust relations within communities; and adequate design of institutions, including financial resources. International Financial Institutions (IFIs) should thus focus on building governance capacity rather than further engaging in state-building, which has failed despite substantial investments. If the central state is autocratic and/or predatory, building state capacity will only make a bad situation worse. Yet, if the central government is constrained by the rule of law and by democratic institutions, but lacks the capacity to implement and enforce decisions, then capacity-building might help improve governance.