The new oxofluoride Cu7(TeO3)6F2 has been synthesized by hydrothermal synthesis. It crystallizes in the triclinic system, space group P1̅. The crystal structure constitutes a Cu–O framework with ...channels extending along 001 where the F– ions and the stereochemically active lone-pairs on Te4+ are located. From magnetic susceptibility, specific heat, and Raman scattering measurements we find evidence that the magnetic degrees of freedom of the Cu–O–Cu segments in Cu7(TeO3)6F2 lead to a mixed dimensionality with single Cu S = 1/2 moments weakly coupled to spin-chain fragments. Due to the weaker coupling of the single moments, strong fluctuations exist at elevated temperatures, and long-range magnetic ordering evolves at comparably low temperatures (T N = 15 K).
Carbon dioxide removal from flue gas via swing adsorption processes requires adsorbents with a high CO2 selectivity and capacity. These properties are particularly valuable to reduce the cost of ...carbon capture and storage (CCS). Zeolite NaKA was studied for its ability to selectively adsorb CO2 from flue gas, as we previously observed that zeolite NaKA, with a K+/(K+ + Na+) ratio of 17 atomic%, was highly selective towards CO2 over N2 adsorption by tuning the size of the pore window apertures 1. The reduced pore apertures may, however, retard the adsorption rate of CO2. Here, we studied the kinetics of CO2 adsorption on regularly sized zeolite NaKA and on nano-sized zeolite NaKA. We used in situ infrared (IR) spectroscopy and observed that CO2 physisorbed relatively rapidly. Density functional theory (DFT) was used for quantum chemical calculations, and the results indicated that CO2 molecules bridged across two or three Na+ ions in the samples with no or very small amount of K+. When more K+ ions are present the CO2 molecules no longer bridged across multiple metal ions and adopted an end-on configuration. The calculation showed a shift in the stretching vibration frequency of physisorbed CO2 as observed by IR spectroscopy. Nano-sized zeolite NaKA were synthesised and studied to improve the rate of CO2 adsorption, as the diffusion rate typically increases quadratically with decreasing particle size. Still, the CO2 adsorption rate on nano-sized zeolites NaA and NaKA did not increase significantly. For nano-sized zeolite NaA, we speculate that the absence of such an increased rate is an effect from a skin layer that had formed on the nano-sized zeolite NaA, a layer that was possibly related to intergrowths with extremely small crystals on the surface. The apparently slow adsorption kinetics of CO2 on nano-sized zeolite NaKA was more difficult to explain because it could relate to imperfections within the small crystals, remaining water, or other effects. Overall, the CO2 adsorption rates on zeolite NaKA crystals of different sizes were fast and relevant for the time scales required for adsorption based CCS processes, such as vacuum and temperature swing adsorption (VSA/TSA).
The new oxofluoride Cu-7(TeO3)(6)F-2 has been synthesized by hydrothermal synthesis. It crystallizes in the triclinic system, space group P (1) over bar. The crystal structure constitutes a Cu-O ...framework with channels extending along 001 where the F- ions and the stereochernically active lone-pairs on Te4+ are located. From magnetic susceptibility, specific heat, and Raman scattering measurements we find evidence that the magnetic degrees of freedom of the Cu-O-Cu segments in Cu-7(TeO3)(6)F-2 lead to a mixed dimensionality with single Cu S = 1/2 moments wealdy coupled to spin-chain fragments. Due to the weaker coupling of the single moments, strong fluctuations exist at elevated temperatures, and long-range magnetic ordering evolves at comparably low temperatures (T-N = 15 K).
Herein, we report the performance of a photocatalytic system based on visible-light active MIL-125-NH
2
mixed with nickel phosphide (Ni
2
P) nanoparticles. This combination boosts the H
2
evolution ...rate to an outstanding value of 894 μmol h
−1
g
−1
under visible-light irradiation, which is among the highest H
2
evolution rates reported to date for metal-organic frameworks (MOFs). The H
2
generation rate exhibited by Ni
2
P/MIL-125-NH
2
is almost 3 times higher than that of the Pt/MIL-125-NH
2
system, highlighting the impact of the co-catalyst on photocatalytic water splitting. Additionally, our system outperforms the Ni
2
P/TiO
2
system under UV-vis irradiation. The exceptional performance of Ni
2
P/MIL-125-NH
2
is due to the efficient transfer of photogenerated electrons from MIL-125-NH
2
to Ni
2
P, high intrinsic activity of Ni
2
P and exceptional synergy between them. This system exhibits the highest apparent quantum yields of 27.0 and 6.6% at 400 and 450 nm, respectively, ever reported for MOFs.
We showcase the key role of the co-catalyst when combined with MIL-125-NH
2
towards the photocatalytic H
2
generation.
Connecting science and policy to promote the effective management of marine resources is a necessity and challenge acknowledged by scientists, policymakers, and stakeholders alike. As a leader on ...ocean issues, California has recognized the importance of integrating science into ocean and coastal management through specific policy choices. An example is the establishment of the California Ocean Science Trust (OST), a non-profit organization mandated to support management decisions with the best available science. The OST functions as a "boundary organization" bridging the often-disparate worlds of science and policy. Recently, while coordinating a scientific study on the controversial issue of decommissioning California's offshore oil and gas platforms, the OST encountered public misconceptions about the peer review process and how it can help ensure unbiased scientific information informs policy. The OST's experience with this study, and generally as a scientific knowledge broker, provides a practical perspective on techniques for navigating the choppy waters between science and policy. This article presents a critical reflection on the OST's experience coordinating the platform decommissioning study, examined through the framework of boundary organizations and salience, credibility, and legitimacy. It highlights lessons-learned from the project and shares recommendations for working toward the effective integration of science and policy.
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