Controllable synthesis of Co nanoparticles with the assistance of cucurbit[6]uril and its efficient photoelectrochemical catalysis in water splitting on a g-C3N4 photoanode

Photoelectrochemical water splitting based on g-C3N4 is considered as a promising approach to oxygen generation. Hereinto, an innovative photoanode, g-C3N4/Q[6]-Co NPs, is successfully fabricated by depositing a Co nanocatalyst on the surface of a g-C3N4 film. The nanoparticles are prepared by reduction of a coordination compound of Co[ii]-cucurbit[6]uril, in which the macrocycle served as a template and supporter. The resulting g-C3N4/Q[6]-Co NPs provided a significant improvement of the photocurrent density (393 mu A cm(-2) at 1.23 V vs. RHE) and a higher photoconversion efficiency (0.02419%) than the pristine g-C3N4 catalyst. These results reveal that the high visible light absorption of g-C3N4/Q[6]-Co NPs ensures the formation of a large number of photogenerated electron-hole pairs, and therefore the holes are immediately transferred to the g-C3N4 film through the semiconductor-metal interface, inhibiting the charge recombination process and increasing the photocurrent performance. The approach proposed in this study not only provides a new strategy, in which a macrocyclic compound is employed as the template and supporter in the synthetic process of the nanocatalyst, but also opens a new window for the application of g-C3N4 in PEC water splitting.

Automated summary

In this study, an innovative photoanode material g-C3N4/Q[6]-Co NPs was successfully fabricated, which showed significant improvement in photocurrent density and photoconversion efficiency compared to the pristine g-C3N4 catalyst. The high visible light absorption of g-C3N4/Q[6]-Co NPs ensured the formation of a large number of photogenerated electron-hole pairs, and the holes were transferred to the g-C3N4 film through the semiconductor-metal interface, inhibiting charge recombination and enhancing photocurrent performance.