钟地长/鲁统部Angew：石墨烯共价锚定COFs光催化CO2还原为甲酸盐或CO

第一作者天津理工大学Yun-Nan Gong、Jian-Hua Mei，通讯作者天津理工大学钟地长、鲁统部在《Angewandte Chemie International Edition》发表题为《Boosting CO2 Photoreduction to Formate or CO with High Selectivity over a Covalent Organic Framework Covalently Anchored on Graphene Oxide》重要成果！

共价有机框架(COFs)在光催化CO₂还原反应(CO₂RR)中得到了广泛研究。然而，由于光生电子和空穴的快速重组，原始COFs通常表现出较低的催化效率。在本研究中，作者将COF-366-Co共价锚定在氧化石墨烯(GO)表面，制备了一种稳定的COF-366-Co复合材料(GO-COF-366-Co)，用于光催化CO₂还原。有趣的是，在绝对乙腈(CH₃CN)中，GO-COF-366-Co对CO₂光还原生成甲酸的选择性高达94.4%，甲酸产率为15.8 mmol/g，约为原始COF-366-Co的4倍。相比之下，在CH₃CN/H₂O (v:v = 4:1)条件下，GO-COF-366-Co光催化还原CO₂的主要产物是CO (96.1%)， CO产率高达52.2 mmol/g，也比使用原始COF-366-Co提高了约4倍。光电化学实验表明，COF-366-Co与GO共价键形成的GO-COF-366-Co复合材料显著促进了电荷的分离和转移，从而提高了催化活性。此外，理论计算和原位傅里叶变换红外光谱分析表明，H₂O可以通过O-h (aq)···O(*COOH)氢键稳定*COOH中间体，进一步形成*CO中间体，从而解释了调节光催化性能的原因。

Scheme 1. Schematic of the fabrication of GO-COF-366-Co for photocatalytic CO2 reduction to HCOO- or CO.

Figure 1. (a) SEM image of GO-COF-366-Co. (b) HR-TEM image of GO-COF-366-Co (the lattice fringe of 2.05 nm is attributed to the (200) face of COF-366-Co). (c) XPS spectra of GO-COF-366-Co and COF-366-Co. (d) Powder XRD patterns of GO-COF-366-Co after treatment in 0.1 M HCl and 20 M NaOH for 24 h.

Figure 2. (a) HCOO- yields over GO-COF-366-Co, COF-366-Co, and GO/COF-366-Co after 8 h of reaction in CH3CN. (b) CO yields of GO-COF-366-Co, COF-366-Co, and GO/COF-366-Co after 8 h of reaction in CH3CN/H2O (v:v = 4:1). (c) 13C NMR spectra of the liquid product obtained from the photocatalytic CO2RR over GO-COF-366-Co in CH3CN using 13CO2 instead of 12CO2. (d) Mass spectrum of the gaseous product obtained from the photocatalytic CO2RR over GO-COF-366-Co in CH3CN/H2O (v:v = 4:1) using 13CO2 instead of 12CO2.

Figure 3. (a) Photocurrent tests and (b) EIS plots of GO-COF-366-Co, COF-366-Co, and GO/COF-366-Co. (c) CV curves of GO-COF-366-Co and COF-366-Co. (d) EPR spectra of GO-COF-366-Co with [Ru(phen)3](PF6)2 in the dark and under light irradiation.

Figure 4. Gibbs free energy diagrams for CO2 photoreduction to HCOO- and CO in (a) CH3CN and (b) CH3CN/H2O. In situ FTIR spectra of GO-COF-366-Co for CO2 photoreduction in CH3CN (c) and CH3CN/H2O (d).

Boosting CO2 Photoreduction to Formate or CO with High Selectivity over a Covalent Organic Framework Covalently Anchored on Graphene Oxide

https://doi.org/10.1002/anie.202318735