“碳中和”专刊系列文章（十）｜结晶氮化碳纳米片/超细三氧化钨纳米粒子构筑的S型异质结用于光催化二氧化碳还原

S-scheme heterojunction of crystalline carbon nitride nanosheets and ultrafine WO₃ nanoparticles for photocatalytic CO₂ reduction

Gongjie Chen, Ziruo Zhou, Bifang Li, Xiahui Lin^*, Can Yang^*, Yuanxing Fang, Wei Lin, Yidong Hou, Guigang Zhang, Sibo Wang*

https://doi.org/10.1016/j.jes.2023.05.028

高度结晶的氮化碳聚合物在光催化水全分解方面展示出巨大的潜能；然而，它们在光驱动CO₂催化转化方面仍处于探索阶段。在本工作中，作者通过KCl/LiCl熔盐介导的双氰胺缩聚制备了嵌有melon的聚三嗪酰亚胺（PTI）结晶氮化碳纳米片（CCN），随后在其表面沉积超小WO₃纳米粒子，构建具有S型载流子传输界面的CCN/WO₃异质结。系统的物化分析手段被用于揭示具有S型界面的CCN/WO₃复合物的组成和结构特征，测试结果表明CCN/WO₃异质结催化剂具备增强的光学捕获、强化的CO₂吸附和活化、较佳织构特性以及光致载流子的空间分离和定向运动等特征。在温和反应条件下，最优组成的CCN/WO₃催化剂展现出优异的光催化CO₂还原为CO的活性，其中CO生成速率为23.0 μmol/hr（即2300 μmol/(hr·g)），约为原始CCN的7倍。同时，相对H₂而言，CO选择性高达90.6%。CCN/WO₃催化剂还表现出的高稳定性和良好的可重复使用性。此外，通过原位漫反射红外傅里叶变换光谱（DRIFTS）监测催化剂上的CO₂吸附和转化过程，确定了CO₂^∗−、COOH^∗和CO^∗的关键中间体。结合性能评估结果，提出了可能的CO₂还原机制。

S型CCN/WO₃异质光催化剂具有宽光谱响应能力，能够有效增强CO₂吸附/活化，并促进光电荷分离和迁移。最优组成的CCN/WO₃异质结具有优异的光催化CO₂还原为CO的性能，约为原始CCN的7倍，并且CO的选择性高达90.6%。

Highly crystalline carbon nitride polymers have shown great opportunities in overall water photosplitting; however, their mission in light-driven CO₂ conversion remains to be explored. In this work, crystalline carbon nitride (CCN) nanosheets of poly triazine imide (PTI) embedded with melon domains are fabricated by KCl/LiCl-mediated polycondensation of dicyandiamide, the surface of which is subsequently deposited with ultrafine WO₃ nanoparticles to construct the CCN/WO₃ heterostructure with a S-scheme interface. Systematic characterizations have been conducted to reveal the compositions and structures of the S-scheme CCN/WO₃ hybrid, featuring strengthened optical capture, enhanced CO₂ adsorption and activation, attractive textural properties, as well as spatial separation and directed movement of light-triggered charge carriers. Under mild conditions, the CCN/WO₃ catalyst with optimized composition displays a high photocatalytic activity for reducing CO₂ to CO in a rate of 23.0 µmol/hr (i.e., 2300 µmol/(hr·g)), which is about 7-fold that of pristine CCN, along with a high CO selectivity of 90.6% against H₂ formation. Moreover, it also manifests high stability and fine reusability for the CO₂ conversion reaction. The CO₂ adsorption and conversion processes on the catalyst are monitored by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), identifying the crucial intermediates of CO₂^*−, COOH^* and CO^*, which integrated with the results of performance evaluation proposes the possible CO₂ reduction mechanism.

第一作者

陈躬杰于2023年在福州大学化学学院获得硕士学位。主要从事催化材料的调控设计，CO₂催化转化等相关研究。在J. Environ. Sci., Sustain. Energ. Fuels国际期刊发表文章2篇。

通讯作者

汪思波，福州大学教授。主要从事半导体材料的设计、合成及光催化还原二氧化碳、光解水制氢等性能研究，初步取得一些研究进展。迄今，共发表SCI论文60余篇，他引8000余次，发表第一/通讯作者论文30余篇，包括 J. Am. Chem. Soc.、Angew. Chem. Int. Ed.、Adv. Mater.、Energy Environ. Sci.等；入选2020-2022年科睿唯安“全球高被引学者”。

https://www.sciencedirect.com/science/article/pii/S1001074223002279

Gongjie Chen, Ziruo Zhou, Bifang Li, Xiahui Lin, Can Yang, Yuanxing Fang, Wei Lin, Yidong Hou, Guigang Zhang, Sibo Wang, 2024. S-scheme heterojunction of crystalline carbon nitride nanosheets and ultrafine WO₃ nanoparticles for photocatalytic CO₂ reduction. J. Environ. Sci. 140, 103-112.