A benzothiazole-based derivative aggregation-induced emission (AIE) fluorescent ‘turn-on’ probe named 2-(2-((4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)oxy)phenyl)benzo[d]thiazole (probe BT-BO) was developed and synthesized successfully for detecting hydrogen peroxide (H₂O₂) in living cells. The synthesis method of probe BT-BO is facile. Probe BT-BO demonstrates a well-resolved emission peak at 604 nm and the ability to prevent the interference of reactive oxygen species (ROS), various metal ions and anion ions, and good sensitivity. Additionally, the probe boasts impressive pH range versatility, a fast response time to H₂O₂ and low cytotoxicity. Finally, probe BT-BO was applied successfully to image A549 and Hep G2 cells to monitor both exogenous and endogenous H₂O₂.

A serial of Cu₂O/activated carbon (AC) and Cu⁰/AC catalysts were prepared in situ and evaluated in methanol oxidative carbonylation to clarify the mechanistic differences between Cu₂O and Cu⁰ active species. It was found that both species are catalytically active, but Cu₂O exhibits significantly higher efficiency than Cu⁰. Feeding sequence studies reveal that, on Cu₂O, co-adsorbed CH₃O and CO react via the L–H mechanism to form CH₃OCO intermediates, a favorable pathway for DMC formation; on Cu⁰, however, CH₃OCO forms via the E–R mechanism between adsorbed CH₃O and gaseous CO, which is less efficient. Moreover, deactivation is mainly due to copper oxidation, which is sequence-dependent but valence-independent. This study highlights Cu₂O as the superior active center and offers fundamental understanding of copper valence-dependent catalysis in methanol oxidative carbonylation.