Dipole field in nitrogen-enriched carbon nitride with external forces to boost the artificial photosynthesis of hydrogen peroxide.

Li, Zhi; Zhou, Yuanyi; Zhou, Yingtang; Wang, Kai; Yun, Yang; Chen, Shanyong; Jiao, Wentao; Chen, Li et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Artificial photosynthesis is a promising strategy for efficient hydrogen peroxide production, but the poor directional charge transfer from bulk to active sites restricts the overall photocatalytic efficiency. To address this, a new process of dipole field-driven spontaneous polarization in nitrogen-rich triazole-based carbon nitride (C<sub>3</sub>N<sub>5</sub>) to harness photogenerated charge kinetics for hydrogen peroxide production is constructed. Here, C<sub>3</sub>N<sub>5</sub> achieves a hydrogen peroxide photosynthesis rate of 3809.5 µmol g<sup>-1</sup> h<sup>-1</sup> and a 2e<sup>-</sup> transfer selectivity of 92% under simulated sunlight and ultrasonic forces. This high performance is attributed to the introduction of rich nitrogen active sites of the triazole ring in C<sub>3</sub>N<sub>5</sub>, which brings a dipole field. This dipole field induces a spontaneous polarization field to accelerate a rapid directional electron transfer process to nitrogen active sites and therefore induces Pauling-type adsorption of oxygen through an indirect 2e<sup>-</sup> transfer pathway to form hydrogen peroxide. This innovative concept using a dipole field to harness the migration and transport of photogenerated carriers provides a new route to improve photosynthesis efficiency via structural engineering.