Significantly enhanced photothermal catalytic CO2 reduction over TiO2/g-C3N4 composite with full spectrum solar light.

Using solar energy to drive catalytic conversion of CO2 into value-added chemicals has great potential to alleviate the global energy shortage and anthropogenic climate change. Herein, a "hitting three birds with one stone" strategy was reported to prepared boron-doped g-C3N4/TiO2-x composite (BCT) by a one-step thermal reduction process. A series of characterizations showed that the composite catalyst has extended full-spectrum absorption, rapid photogenerated charge separation, and outstanding CO2 photoreduction performance (265.2 µmol g-1h-1), which is 7.5 and 9.2 times higher than that of pure TiO2 and g-C3N4, respectively. In addition, the CO2 conversion rate can be further increased to 345.1 µmol g-1h-1 at 70 °C due to its excellent photothermal conversion. Mechanistic studies reveal that synergistic effects alter the charge density distribution, thereby lowering the energy barrier for CO2 conversion by adsorbing and activating CO2 molecules. This work provides a novel three-in-one integrated strategy for fabricating high-efficiency catalysts.

Community centered public safety resilience under public emergencies: A case study of COVID-19.

During public emergencies, the level of public safety will be resilient and follow a process from decline to rise. Regarding the concept and influencing factors of public safety resilience, a three-level public safety resilience framework that includes personal, community, and government levels was proposed in this study. It provided the overall metrics that used the resistance and recovery ability to describe the dynamic characteristics of public safety resilience as well as the resilience assessment indexes on three levels. In the context of the Coronavirus Disease 2019 (COVID-19) pandemic, this study applied the proposed framework in a case study on public safety resilience at the Beihang community, Beijing, China through descriptive statistics, structural equation model, and principal component regression analysis of questionnaire data. The data analysis results showed that community resilience was the most important of the three levels of public safety resilience. In addition, community resilience could improve personal resilience, and government resilience had a positive effect on community and personal resilience. Compared with the resistance ability, the recovery ability was influenced more by the operation and improvement of the community. This study is conducive to understanding and improving public safety resilience on the personal, community, and government levels and can help relevant parties improve their ability to respond to the COVID-19 pandemic. Furthermore, the methods used in this study can be extended to other studies on public emergencies.

A full-spectrum responsive B-TiO2@SiO2-HA nanotheranostic system for NIR-II photoacoustic imaging-guided cancer phototherapy.

The second near-infrared (NIR-II) window (1000-1350 nm) usually offers further improved light penetration, a higher maximum permissible exposure (MPE), and a lower background signal. Development of NIR-II optical diagnosis and phototherapy technologies is of great significance for precise, efficient tumor therapy. In this work, a new type of Ti-based targeting agent (B-TiO2@SiO2-HA) nanotheranostic system with strong NIR-II absorption was designed and fabricated for the first time. Oxygen vacancies were formed in B-TiO2 and its band gap was narrowed, resulting in nanotheranostic systems with full-spectrum responses to stimulation with light. The experimental results showed that B-TiO2@SiO2-HA not only can enable high NIR-II photothermal conversion and provide excellent reactive oxygen species (ROS) production capacity, but also can enable high-resolution photoacoustic imaging (PAI) under NIR-II laser irradiation. Moreover, HA modification gives the nanotheranostic systems the useful ability to target high-CD44-expression tumor cells and tissues. In vitro and in vivo experiments demonstrated that B-TiO2@SiO2-HA exhibited a targeted photothermal/photodynamic (PTT/PDT) effect that produced tumor-cell ablation and apoptosis under the guidance of real-time NIR-II PA imaging. B-TiO2@SiO2-HA exhibits precise nanotheranostic potential for PAI-guided tumor-targeting phototherapy.