Platinum Single Atoms Anchored on a Covalent Organic Framework: Boosting Active Sites for Photocatalytic Hydrogen Evolution,ACS Catalysis

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Platinum Single Atoms Anchored on a Covalent Organic Framework: Boosting Active Sites for Photocatalytic Hydrogen Evolution
ACS Catalysis ( IF 11.3 ) Pub Date : 2021-10-18 , DOI: 10.1021/acscatal.1c03441
Pengyu Dong ₁ , Yan Wang ₂ , Aicaijun Zhang ₂ , Ting Cheng ₁ , Xinguo Xi ₂ , Jinlong Zhang ₃

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It is of great importance to explore and achieve a more effective approach toward the controllable synthesis of single-atom-based photocatalysts with high metal content and long-term durability. Herein, single-atom platinum (Pt) with high loading content anchored on the pore walls of two-dimensional β-ketoenamine-linked covalent organic frameworks (TpPa-1-COF) is presented. Aided by advanced characterization techniques of aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC HAADF-STEM) and X-ray absorption fine structure (XAFS) spectroscopy, it has been demonstrated that atomically dispersed Pt is formed on the TpPa-1-COF support through a six-coordinated C₃N–Pt–Cl₂ species. The optimized Pt₁@TpPa-1 catalyst exhibits a high photocatalytic H₂ evolution rate of 719 μmol g^–1 h^–1 under visible-light irradiation, a high actual Pt loading content of 0.72 wt %, and a large turnover frequency (TOF) of 19.5 h^–1, with activity equivalent to 3.9 and 48 times higher than those of Pt nanoparticles/TpPa-1 and bare TpPa-1, respectively. The improved photocatalytic performance for H₂ evolution is ascribed to the effective photogenerated charge separation and migration and well-dispersed active sites of single-atom Pt. Moreover, density functional theory (DFT) calculations further reveal the role of Pt single atoms in the enhanced photocatalytic activity for H₂ evolution. Overall, this work provides some inspiration for designing single-atom-based photocatalysts with outstanding stability and efficiency using COFs as the support.

中文翻译：

铂单原子锚定在共价有机框架上：促进光催化氢演化的活性位点

探索并实现一种更有效的方法来可控合成具有高金属含量和长期耐久性的单原子基光催化剂具有重要意义。在此，提出了锚定在二维 β-酮烯胺连接的共价有机骨架 (TpPa-1-COF) 孔壁上的具有高负载量的单原子铂 (Pt)。借助像差校正的高角度环形暗场扫描透射电子显微镜 (AC HAADF-STEM) 和 X 射线吸收精细结构 (XAFS) 光谱的先进表征技术，已经证明原子分散的 Pt 形成在通过六配位的 C ₃ N-Pt-Cl ₂物质支持 TpPa-1-COF 。优化的 Pt ₁@ TPPA-1催化剂表现出高的光催化ħ ₂的719微摩尔克进化速率^-1 ħ ^-1 19.5ħ可见光照射下，0.72重量％的高实际Pt负载内容，和一个大周转频率（TOF）^–1，其活性分别相当于 Pt 纳米颗粒/TpPa-1 和裸 TpPa-1 的 3.9 倍和 48 倍。改进的 H ₂析出光催化性能归因于有效的光生电荷分离和迁移以及单原子 Pt 的良好分散的活性位点。此外，密度泛函理论 (DFT) 计算进一步揭示了 Pt 单原子在增强 H ₂光催化活性中的作用进化。总体而言，这项工作为设计具有出色稳定性和效率的单原子基光催化剂提供了一些灵感，该催化剂以 COF 为载体。

更新日期：2021-11-05

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