Current position >About Us
1. The meaning of paddle wheel fan
The meaning of paddle wheel fan is a blade type fan. This is a special type of fan, whose main feature is to generate airflow through the impeller. Here are some key points about the paddle wheel fan: Working principle: The impeller of the blade wheel fan is driven by a motor to rotate, which in turn drives the surrounding air flow to achieve cooling or ventilation effects. Application scenarios: This type of fan is usually used in situations that require efficient air flow, such as industrial cooling, ventilation systems, large equipment, etc. Features: Compared to other types of fans, impeller fans typically have higher air volume and pressure, making them suitable for scenarios that require strong airflow. In summary, a paddle wheel fan, also known as a blade type fan, is a type of fan that generates airflow through the rotation of an impeller. It has a wide range of application scenarios and unique working characteristics.
2. Copper porphyrin MOF promotes photocatalytic CO2 reduction in an aerobic environment
Copper porphyrin MOF (π - π stacking composite photocatalyst combined with ultra-thin graphite phase carbon nitride g-C3N4) promotes photocatalytic CO2 reduction in an aerobic environment. The mechanism and significance are as follows: catalyst synthesis and specific synthesis methods: the team of the Institute of Chemistry of the Chinese Academy of Sciences synthesized a π - π stacking composite photocatalyst by combining ultra-thin graphite phase carbon nitride g-C3N4 and copper based porphyrin MOF two two-dimensional materials. Pre activation effect: After aerobic photocatalytic pre activation of the catalyst, the activated catalyst can catalyze CO2 reduction at an air concentration of oxygen (20%), with a CO2 reduction reaction rate six times faster than under anaerobic conditions. Meanwhile, the presence of oxygen enhances the stability of the catalytic reaction, and the improvement in catalytic performance shows a significant dependence on oxygen concentration. The mechanism of aerobic environment promoting photocatalytic CO2 reduction: Coordination structure changes: X-ray detailed absorption spectroscopy (XAFS) and in-situ infrared spectroscopy experiments show that during the aerobic photocatalytic pre activation process of the catalyst, the pad wheel copper node (Cu2 (COO) 8) of MOF undergoes coordination structure changes, and the hydroxyl group (- OH) generated by oxygen reduction partially replaces the carboxyl group (- COO -) originally coordinated with copper, resulting in hydroxylation of the copper node. Structural stability difference: Under aerobic CO2 reduction reaction conditions, the hydroxylated copper nodes generated by pre activation can maintain stability; The anaerobic CO2 reduction process can lead to a decrease in copper valence state and desorption of hydroxyl groups in the node structure, resulting in different catalytic reaction structures and CO2 reduction reaction rates in aerobic and anaerobic environments. Activation energy change and preferential adsorption: Theoretical calculations have found that at hydroxylated copper nodes, the activation energy for CO2 reduction significantly decreases, while the activation energy required for oxygen reduction significantly increases. At the same time, hydroxyl groups promote the preferential adsorption of CO2 at the reaction site, ensuring that CO2 reduction takes priority over oxygen reducti