Vacancies engineering in ultrathin porous g-C3N4 tubes for enhanced photocatalytic PMS activation for imidacloprid degradation.

The ultrathin porous g-C 3 N 4 tubes with three-coordinated nitrogen vacancies work to remarkably degrade pesticide contaminants under photocatalysis coupling peroxymonosulfate activation system. [Display omitted] • Ultrathin porous g-C 3 N 4 tubes with three-coordinated nitrogen (N b) vacancies was successfully constructed. • Prepared g-C 3 N 4 achieves a remarkable 100% degradation of imidacloprid within 20 min under the PC-PMS system. • Engineering N b vacancies and ultrathin porous architecture achieve the enhanced photogenerated carrier utilization and enriched active sites. • The study achieve the efficient utilization of electron-hole pairs conversion to ∙O 2 – and 1O 2 for the removal of imidacloprid in PC-PMS system. Precise morphology and vacancy engineering is a promising strategy to enhance the degradation performance of refractory contaminants in photocatalysis coupling peroxymonosulfate activation (PC-PMS) systems. In this context, we developed ultrathin porous g-C 3 N 4 tubes with three-coordinated nitrogen (N b) vacancies between the heptazine units through hydrogen intercalated exfoliation and selective nitrogen removal at high temperatures. The ultrathin porous tubular architecture provides an ultrahigh-specific surface area with abundant exposed active sites, ensures effective mass transfer, and shortens the diffusion distance of photogenerated carriers. The N b vacancies act as unsaturated sites, inhibiting the photogenerated carrier's recombination and facilitating the adsorption/activation of O 2 and its conversion to ∙O 2 – via photogenerated electrons. Then, the PMS is subsequently oxidated by photogenerated holes selectively producing 1O 2. Together, these continuously released free radicals unlock the complete degradation of imidacloprid within 20 min in the PC-PMS system, with a degradation rate about 350 % higher than conventional g-C 3 N 4 tubes and 10-fold that of pristine g-C 3 N 4. This study provides a novel insight into the efficient utilization of photogenerated electron-hole pairs conversion to ∙O 2 – and 1O 2 for the removal of pesticide contaminants through the rational design of photocatalysts in the PC-PMS system. [ABSTRACT FROM AUTHOR]