Hydrogen-Bonded Cocrystals Encapsulating CsPbBr3 Perovskite Nanocrystals with Enhancement of Charge Transport for Photocatalytic Reduction of Uranium

At present, poor stability and carrier transfer efficiency are the main problems that limit the development of perovskite-based photoelectric technologies. In this work, hydrogen-bonded cocrystal-coated perovskite composite (PeNCs@NHS-M) is easily obtained by inducing rapid crystallization of melamine (M) and N-hydroxysuccinimide (NHS) with PeNCs as the nuclei. The outer NHS-M cocrystal passivates the undercoordinated lead atoms by forming covalent bonds, thereby greatly reducing the trap density while maintaining good structure stability for perovskite nanocrystals. Moreover, benefiting from the interfacial covalent band linkage and long-range ordered structures of cocrystals, the charge transfer efficiency is effectively enhanced and PeNCs@NHS-M displays superior photoelectric performance. Based on the excellent photoelectric performance and abundant active sites of PeNCs@NHS-M, photocatalytic reduction of uranium is realized. PeNCs@NHS-M exhibits U(VI) reduction removal capability of up to 810.1 mg g-1 in the presence of light. The strategy of cocrystals trapping perovskite nanocrystals provides a simple synthesis method for composites and opens up a new idea for simultaneously improving the stability and photovoltaic performance of perovskite. The CsPbBr3 nanocrystals (PeNCs) are coated with hydrogen-bonded cocrystals (N-hydroxysuccinimide-melamine, NHS-M) to achieve defect passivation and structural stability enhancement. Moreover, this covalently linked heterostructure further promotes the electron transport of PeNCs and realizes the photocatalytic reduction of uranium through the binding sites on the cocrystal.image