电子顺磁共振
X射线光电子能谱
材料科学
密度泛函理论
光催化
结晶学
物理化学
催化作用
化学
计算化学
核磁共振
生物化学
物理
作者
M. Wang,Shiying Fan,Xinyong Li,Jie Shi,Yan Mao,Yang Yang,Li Gao
标识
DOI:10.1021/acsami.3c14110
摘要
Efficiently upgrading 5-hydroxymethylfurfural (HMF) into high-value-added products, such as 2,5-diformylfuran (DFF) and 2,5-furan dicarboxylic acid (FDCA), through a photocatalytic process by using solar energy has been incessantly pursued worldwide. Herein, a series of transition-metal (TM = Ni, Fe, Co, Cu) single atoms were supported on Ti4+αTi3+1-αO2-δ nanofibers (NFs) with certain defects (Ov), denoted as TM SAC-Ti4+αTi3+1-αO2-δ NFs (TM = Ni, Fe, Co, Cu), aiming to enhance the photocatalytic conversion of HMF. A super HMF conversion rate of 57% and a total yield of 1718.66 μmol g-1 h-1 (DFF and FDCA) surpassing that of the Ti4+αTi3+1-αO2-δ NFs by 1.6 and 2.1 times, respectively, are realized when TM is Co (Co SAC-Ti4+αTi3+1-αO2-δ NFs). Experiments combined with density functional theory calculation (DFT) demonstrate that the TM single atoms occupy the Ti site of Ti4+αTi3+1-αO2-δ NFs, which plays a dominant role in the photo-oxidation of HMF. Raman, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) characterizations confirm the strong electron local exchange interaction in TM SAC-Ti4+αTi3+1-αO2-δ NFs and demonstrate the substitution of Ti by the TM SACs. The projected density of states and charge density difference reveal that the strong interaction between metal-3d and O-2p orbitals forms Ti-O-TM bonds. The bonds are identified as the adsorption site, where TM single atoms on the surface of Ti4+αTi3+1-αO2-δ NFs reduce HMF molecule adsorption energy (Eads). Furthermore, the TM single atom modulates the electronic structure of TM SAC-Ti4+αTi3+1-αO2-δ NFs through electron transfer, leading to narrow band gaps of the photocatalysts and enhancing their photocatalytic performance. This study has uncovered a newer strategy for enhancing the photocatalytic attributes of semiconducting materials.
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