Original English Title: Mesoporous Carbon Nitride with π‑Electron-Rich Domains and Polarizable Hydroxyls Fabricated via Solution Thermal Shock for Visible-Light Photocatalysis
Corresponding Authors: Dr. Jiajia Zhang, Fudan University; Professor Hongbin Lu, Fudan University
Authors: Zhimin Zhai (翟志敏), Huihui Zhang (张慧慧) , Fushuang Niu (牛富双), Peiying Liu (刘沛莹)
Background Introduction
In recent years, with the concept of carbon neutrality being proposed, green hydrogen has become increasingly important. Photocatalytic water splitting has become a competitive strategy for converting solar energy into high energy density renewable hydrogen energy. Carbon nitride has advantages such as thermal stability, low production cost, and adjustable structure, making it very attractive in the field of photocatalysis. However, when the light absorption band extends into the visible light or even near-infrared region, the increased Coulomb force of the singlet Frenkel excitons inhibits the separation of photogenerated charge carriers, resulting in unsatisfactory photocatalytic activity in the visible light range. Therefore, how to maintain high exciton dissociation while increasing the visible light absorption range of carbon nitride has become a challenging problem in this field.
Article Highlights
Recently, Dr. Jiajia Zhang and Professor Hongbin Lu from Fudan University published a study on the preparation of πACS Nano on the use of solution thermal shock to fabricate π-electron-rich and hydroxylated mesoporous carbon nitride for visible light photocatalysis. By introducing mesoporous structures, π-electron richness, and polarizable hydroxyl functional groups into carbon nitride based on the solution thermal shock strategy (Figure 1), the visible light absorption range of carbon nitride was significantly improved, extending up to 1000 nm, while the π-electron richness and polarizable hydroxyl functional groups facilitated the spatial separation of photogenerated electrons and holes, and the porous structure provided more active sites, ultimately enhancing the photocatalytic activity of carbon nitride.
Figure 1. Preparation strategy, process analysis, and samples of carbon nitride.
Through testing the photocatalytic hydrogen production activity of the modified carbon nitride, it was found that this carbon nitride exhibited significant photocatalytic hydrogen evolution performance, with the performance improved by 17.5 times compared to the thermally treated carbon nitride prepared by traditional strategies (Figure 2). This may be due to the synergistic promotion of the porous structure, π-electron richness, and hydroxyl functional groups (Figure 2). The mesoporous structure can endow carbon nitride with a larger specific surface area, more reaction sites, and a shorter diffusion path for photogenerated electrons to transfer from the interior to the edge; the π-electron richness can significantly reduce the charge transfer resistance of carbon nitride, enhancing the spatial separation of photogenerated holes and electrons; hydroxyl groups help in the separation and transfer of photogenerated carriers, making carbon nitride more hydrophilic and enhancing proton reduction capability.
Figure 2. Photocatalytic performance, computational results, and mechanism analysis of carbon nitride..
Conclusion/Outlook
The research team proposed a solution thermal shock strategy to suppress the phase separation of different components and the mismatch of initial/platform decomposition temperatures, resulting in carbon nitride with a porous structure, π-electron richness, and polarizable hydroxyl functional groups. The designed carbon nitride exhibited good visible light photocatalytic activity, overcoming the challenge of weakened exciton dissociation caused by the increased Coulomb force of singlet Frenkel excitons due to the narrowing band gap. At the same time, the multi-structural design integrated carbon nitride developed in this work provides a new idea for the structural and performance optimization of other nanomaterials. The related paper was published in ACS Nano, with doctoral student Zhimin Zhai from Fudan University as the first author, and Dr. Jiajia Zhang and Professor Hongbin Lu as corresponding authors.
Corresponding Author Information:
Dr. Jiajia Zhang, Fudan University
Dr. Jiajia Zhang, Assistant Researcher at Fudan University, mainly engaged in the development of two-dimensional confined spaces, preparation of two-dimensional materials, and their applications in catalysis and energy fields. Published papers in journals such as ACS Nano, Chemistry of Materials, Science China-Materials, applied for 15 invention patents, 7 of which have been authorized. Received funding from the Shanghai Star Program, Shanghai Super Postdoctoral Program, and the Ministry of Education Innovation Platform Special Fund.
Professor Hongbin Lu, Fudan University
Professor Hongbin Lu, a second-level professor at Fudan University, specially invited expert from the Shandong Academy of Pharmaceutical Sciences, dedicated to the high-performance of polymer materials, large-scale preparation and application of low-dimensional materials such as graphene, proposed a series of new methods for the large-scale preparation of differentiated graphene and its composites, published over 100 papers in journals such as Nature Communications, ACS Nano, Nano-Micro Letters, Energy Storage Materials, applied for 71 invention patents, 43 of which have been authorized, including 1 authorized US patent, received the National Science and Technology Progress Second Prize, China Industry-University-Research Cooperation Promotion Award, and Sinopec Science and Technology Progress First Prize, served as a review expert for key R&D program reviews, and a reviewer for journals such as Nature.
Personal Homepage:
http:// lugroup.fudan.edu.cn
Publication Information:
ACS Nano 2022, ASAP
Publication Date: November 30, 2022
https://doi.org/10.1021/acsnano.2c08643
Copyright © 2022 American Chemical Society
