Frustrated Lewis pairs on pentacoordinated Al3+-enriched Al2O3 promote heterolytic hydrogen activation and hydrogenation.

As an emerging class of metal-free catalysts, frustrated Lewis pairs (FLPs) catalysts have been greatly constructed and applied in many fields. Homogeneous FLPs have witnessed significant development, while limited heterogeneous FLPs catalysts are available. Herein, we report that heterogeneous FLPs on pentacoordinated Al3+-enriched Al2O3 readily promote the heterolytic activation of H2 and thus hydrogenation catalysis. The defect-rich Al2O3 was prepared by simple calcination of a carboxylate-containing Al precursor. Combinatorial studies confirmed the presence of rich FLPs on the surface of the defective Al2O3. In contrast to conventional alumina (γ-Al2O3), the FLP-containing Al2O3 can activate H2 in the absence of any transition metal species. More importantly, H2 was activated by surface FLPs in a heterolytic pathway, leading to the hydrogenation of styrene in a stepwise process. This work paves the way for the exploration of more underlying heterogeneous FLPs catalysts and further understanding of accurate active sites and catalytic mechanisms of heterogeneous FLPs at the molecular level.

A Multi-Site Cross-Sectional Study of Anxiety Symptoms and the Associated Factors Among Chinese Drug Users Undergoing Compulsory Detoxification Treatment.

Compulsory drug detoxification treatment (CDT) is currently the major drug rehabilitation modality in China, and drug users often suffer from extraordinary levels of stress during CDT, leading to a high prevalence of anxiety symptoms. This study assesses anxiety symptoms of the drug users undergoing CDT and explores the associated factors. A cross-sectional study with cluster sampling was conducted in three cities in Liaoning Province of Northeast China. Nine hundred CDT drug users were interviewed face-to-face with Chinese questionnaires. Hierarchical multiple regression (HMR) analysis was conducted to explore the factors associated with anxiety symptoms. The prevalence of anxiety symptoms among the CDT drug users was substantially high (33.2%). HMR analysis indicated perceived stress and characteristics of drug use such as types of drugs, were the most important contributors to anxiety symptoms. Optimism (LOT-R) played a protective role in reducing anxiety symptoms in this population. Anxiety symptoms of drug users undergoing CDT were present in a significant proportion of the CDT population. Optimism is a protective factor which could attenuate the detrimental effects of perceived stress on anxiety symptoms and potentially improve treatment outcomes.

Visualizing the growth process of sodium microstructures in sodium batteries by in-situ 23Na MRI and NMR spectroscopy.

The growth of sodium dendrites and the associated solid electrolyte interface (SEI) layer is a critical and fundamental issue influencing the safety and cycling lifespan of sodium batteries. In this work, we use in-situ 23Na magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) techniques, along with an innovative analytical approach, to provide space-resolved and quantitative insights into the formation and evolution of sodium metal microstructures (SMSs; that is, dendritic and mossy Na metal) during the deposition and stripping processes. Our results reveal that the growing SMSs give rise to a linear increase in the overpotential until a transition voltage of 0.15 V is reached, at which point violent electrochemical decomposition of the electrolyte is triggered, leading to the formation of mossy-type SMSs and rapid battery failure. In addition, we determined the existence of NaH in the SEI on sodium metal with ex-situ NMR results. The poor electronic conductivity of NaH is beneficial for the growth of a stable SEI on sodium metal.