Abstract: Disclosed herein are methods of producing photocatalysts for degrading NOx. According to some embodiments of the present disclosure, the method comprises mixing a transitional metal or its oxide with a bone powder or a shell powder, followed by heating the mixture for at least 12 hours to dehydrate the mixture, and calcinating the dehydrated product for 1-5 hours. In certain embodiments, the bone powder is mixed with titanium dioxide at the weight ratio of 1:1. In certain embodiments, the shell powder is mixed with titanium dioxide at the weight ratio of 0.5:1 to 2:1 (w/w).

Abstract: Disclosed herein are methods of producing photocatalysts for degrading NOx. According to some embodiments of the present disclosure, the method comprises mixing a transitional metal or its oxide with a bone powder or a shell powder, followed by heating the mixture for a least 12 hours to dehydrate the mixture, and calcinating the dehydrated product for 1-5 hours. Also disclosed herein are methods of degrading NOx by using the thus-produced photocatalysts. Materials used doped with the transitional metal or its oxide are bone powder and shell powder, which is derived from animals (a chicken, a cow, a pig, a duck, a sheep, a donkey, or a horse) and shells from different species of sea water (a shrimp, a crab, a clam, a barnacle, a snail, an abalone, or an oyster), respectively.

Abstract: Disclosed herein are methods of producing photocatalysts for degrading NOx. According to some embodiments of the present disclosure, the method comprises mixing a transitional metal or its oxide with a bone powder or a shell powder, followed by heating the mixture for a least 12 hours to dehydrate the mixture, and calcinating the dehydrated product for 1-5 hours. Also disclosed herein are methods of degrading NOx by using the thus-produced photocatalysts. Materials used doped with the transitional metal or its oxide are bone powder and shell powder, which is derived from animals (a chicken, a cow, a pig, a duck, a sheep, a donkey, or a horse) and shells from different species of sea water (a shrimp, a crab, a clam, a barnacle, a snail, an abalone, or an oyster), respectively.

Abstract: Disclosed herein is an air cleansing system including an air supplying device and an air cleansing device. The air supplying device is configured to deliver an airflow that contains pollutants therein into the air cleansing device. The air cleansing device comprises an electric generator, which is configured to generate an electrical energy from the airflow. The air cleansing device also comprises an ozone generator, which is driven by the electrical energy and is configured to produce ozone to cleanse the airflow via removing the pollutants therefrom. The air cleansing device is substantially operated without utilizing any additional electrical energy supplied from outside the air cleansing system; and the airflow is substantially cleansed without utilizing any pollutant trapping material to remove the pollutants from the airflow.