To tune its band structure by doping element and to increase the specific surface area by forming micro/nanoscale structures remain the effective means to further improve the photocatalytic performance of graphitic carbon nitride (CN). Herein, Mg- and Cl-codoped CN microtubes (MgCl2-CN) were successfully prepared by a hydrothermal reaction of melamine and magnesium chloride. The specific surface area of 1MgCl2-CN is 148.0 m2/g, about 8.3 times that of CN (17.8 m2/g). Meanwhile, Mg and Cl doping narrows the band gap of CN. Under visible light (λ > 420 nm) irradiation, the photocatalytic hydrogen evolution rate of 1MgCl2-CN reaches 8.4 μmol/h, which is 8.8 times that of CN. The synergistic effect of microtube forming and Mg/Cl doping not only increases the specific surface area, the visible light capture, but also enhances the separation and transfer of photogenerated carriers, thus improving the photocatalytic performance.

Herein, we investigated the photocatalytic degradation of gas‐phase formaldehyde (HCHO) on Pt deposited TiO2 nanowires (Pt/TiO2NW) at continuous flow. Formaldehyde is decomposed into CO2 and H2O in a homemade tube reactor under the LED irradiation. The reactor can monitor online various parameters such as formaldehyde concentration, light intensity, humidity, and temperature. The results indicated that the formaldehyde degradation rate of Pt/TiO2NW increased at continuous flow compared with TiO2 nanowires. Under ultraviolet and visible LED light irradiation, the stable time of degrading low‐concentration formaldehyde by Pt/TiO2NW was 5.6 times that of TiO2NW. Higher ambient humidity facilitates the formaldehyde degradation of Pt/TiO2NW by increasing the hydroxyl radical (.OH) and superoxide radical (.O2- ).

For applicable air purifier to decompose formaldehyde, it is important to develop the TiO2 based photocatalysts that can be irradiated under visible light and can be anchored on soft carbon...

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