Preparation and Photocatalytic Performance of Double-Shelled Hollow W18O49@C3N4@Ti3C2 Microspheres

C3N4, C3N4@Ti3C2 and W18O49@C3N4@Ti3C2 hollow spheres were successfully prepared by using SiO2 template followed by gradual deposition method. The degradation of phenol solution and photolysis ability were tested to characterize its photocatalytic activity. Compared with the single-shelled C3N4 and C3N4@Ti3C2 hollow spheres, double-shelled W18O49@C3N4@Ti3C2 hollow spheres possessed larger surface area and fast charge separation efficiency, exhibiting about 8.9 times and 4.0 times higher H-2 evolution than those of C3N4, C3N4@Ti3C2 hollow spheres, respectively. The photocatalytic mechanism of the W18O49@C3N4@Ti3C2 hollow spheres were carefully investigated according to the results of morphology design and photoelectric performance. A Z scheme mechanism based on the construction of heterojunctions was proposed to explain the improvement of photocatalytic performance. This new charge transfer mechanism appears to greatly inhibit the recombination of electrons/holes during the charge transfer process, while maintaining its strong hydrogen reduction ability, resulting in a higher photocatalytic performance.

Automated summary

The double-shelled W18O49@C3N4@Ti3C2 hollow spheres exhibited significantly higher photocatalytic performance compared to the single-shelled C3N4 and C3N4@Ti3C2 hollow spheres, due to their larger surface area and faster charge separation efficiency. A Z scheme mechanism based on heterojunction construction was proposed to explain the enhanced photocatalytic performance of W18O49@C3N4@Ti3C2 hollow spheres, which effectively inhibited electron/hole recombination during charge transfer while maintaining strong hydrogen reduction ability.