A tris­(bipyridine)­ruthenium­(II) photosensitizer (PS) was anchored to the lipid bilayer of liposomes together with Ru-, Co-, or Ir-based water-oxidation catalysts in order to study the effect of liposomes on photocatalytic water oxidation in the presence of Na2S2O8. The Ru-based and Co-based systems both showed O2 production upon light irradiation, whereas the Ir-based system did not. Membrane anchoring caused a large shift in the quantum yield of oxidative quenching of the photosensitizer excited state by peroxodisulfate, which decreased from 180% in homogeneous solution to 7.3% at the surface of liposomes. For the Ru-based system the electron-transfer rate between the photosensitizer PS+ and the water-oxidation catalyst was increased relative to oxidative quenching. Consequently, the rate-limiting step of the photocatalytic water oxidation reaction at liposomes was oxidative quenching, whereas previous work showed that in homogeneous solution it is the reduction of the oxidized photosensitizer PS+ by the catalyst that limits O2 production. Overall, a lower dioxygen production rate was observed when photocatalytic water oxidation occurred at liposomes, but the stability of the liposomal system increased in comparison to that of the homogeneous system. Such stabilization is caused by the decreased concentration of the unstable PS+ species at liposomes, whereas this species accumulates in homogeneous solution, leading to faster degradation. Overall, liposomal water oxidation was found to be more tolerant to changes in light intensity and electron acceptor concentration, which is an interesting property for the building of solar fuel production devices.

This report showcases five examples of industries applying circular strategies for CRMs: (1) recycling of tungsten carbide scrap by H.C. Starck Tungsten, (2) recycling of battery cathode materials by SungEel Hitech, (3) recovery of rare earth elements from hard disk drives by Hitachi Group, (4) closed rhenium loops by Rolls-Royce, and (5) recovery of platinum group metals by Umicore. The adaptation of business models appears to be one of the biggest enablers of raw material circularity. Ideally, all involved stakeholders (including the manufacturers, the users, and the recyclers) have a common interest in, and are incentivized by retaining the material’s value, which stimulates transparent material flows and close cooperation. This is enabled by retained ownership and with long-term, well-defined relationships between the value chain actors. Such relationships can be enhanced by vertical integration, or by long-term contractual agreements. The benefits of implementing circularity provide a mandate for governmental intervention in stimulating circularity strategies, for example via regulations and subsidies, to overcome initial investment thresholds.

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Life cycle assessment (LCA) databases and software evolve. We analyzed to which extent software and evolving life cycle inventory databases affect the comparison of technology alternatives, using a comparative LCA on permanent magnets as a case study, with two selected software tools: CMLCA and Brightway LCA. We migrated the system models from the CMLCA to Brightway LCA software and alternated between the ecoinvent database versions 2.2 and 3.1 to 3.6 in the system background.When using ecoinvent v3.6 instead of v2.2, the change of the indicator results ranged from −34% to 283%. The evolution of the ecoinvent database impacted the absolute amounts of the characterized results and the relative performance between alternatives. The impact category with the highest variability was ionizing radiation, which even showed a ranking inversion with ecoinvent v3.4. In contrast, the impact of using CMLCA or Brightway was negligible because the same data and modeling assumptions caused percentage differences below 0.4%. During the semi-automated data migration to Brightway, we identified 23 environmental flows in the CMLCA model that were not paired with their corresponding characterization factors in the published study of reference. This error had led to an underestimation of 63% in the photochemical oxidation indicator of one of the alternatives. This underestimation relates to an interoperability issue regarding the nomenclature of environmental flows in software alternatives and is a matter of data implementation rather than an issue intrinsic to the selected software. Finally, we identified improvement opportunities for the transparency and reusability of LCA models. This article met the requirements for a Gold-Gold JIE data openness badge described at http://jie.click/badges.