构建单原子催化剂（SACs）和载体氧空位（OV）的协同催化对于提高CO2加氢催化效率至关重要，但同时也面临着诸多挑战。
近日，黑龙江大学付宏刚教授和刘健聪副教授等人在Science China Materials发表研究论文，开发了一种胺分子辅助原位锚定策略，通过控制胺分子与铂（Pt）物种和TiO2−x之间的相互作用，成功实现Pt单原子在TiO2−x上的有效分散与稳定。
1) 直接证据表明，Pt SACs嵌入OV中形成Ptδ+-OV-Ti3+结构，并展现出强金属-载体相互作用，这不仅抑制了高温还原过程中Pt SACs的烧结，还增强了氢溢流过程，促进了更多OV位点的形成。2) 在逆水煤气变换（RWGS）反应中，增加的OV位点数量可以促进CO2的吸附，而Pt SACs则有效提升了氢的活化和溢流。二者的协同作用显著提高了材料的催化性能，是其在330°C下具有高达9289 h−1的转化频率（TOF）和超过200小时的高稳定性，超越了TiO2−x上负载Pt团簇和纳米颗粒催化剂。本工作为可控制备具有单原子和OV的协同催化剂开辟了一条新的途径。Figure 1. (a) The multistep synthetic process for the PtSA/TiO2−x catalysts. (b, c) SEM and AC-HAADF-STEM images of PtSA/TiO2−x. (d–f) AC-HAADF-STEM images of PtSA/TiO2−x with different regions. Pt single atoms are highlighted in red circles. (g–j) STEM images of PtSA/TiO2−x and the corresponding elemental mapping images of Ti, O and Pt.![]()
Figure 2. (a) Pt 4f XPS spectra of the series Pt/TiO2−x catalysts. (b) In situ CO-DRIFT spectra for the series Pt/TiO2−x catalysts (after Ar purge). (c) H2-TPR profiles for the series Pt–O/TiO2 catalysts. (d) XANES spectra of the Pt L3-edge over the PtSA/TiO2−x, Pt foil and PtO2. (e) Fourier-transformed EXAFS spectra of PtSA/TiO2−x, Pt foil and PtO2. (f) Fourier-transformed magnitudes of Pt L3-edge EXAFS spectra in R space for PtSA/TiO2−x. (g) Fitting results of Fourier-transformed k3-weighted EXAFS in K space of PtSA/TiO2−x. (h–j) Wavelet transform of EXAFS signals of PtSA/TiO2−x, PtO2 and Pt foil. (k, l) The Pt single atom binding energy of Pt on TiO2 (101) surface models; (m, n) The Pt single atom binding energy of Pt on TiO2 (101) OV models.Figure 3. H2-TPD profiles (a), O 1s XPS spectra (b), Ti 2p XPS spectra (c), and EPR spectra (d) of the series Pt/TiO2−x catalysts. (e) Different positions on PtSA/TiO2 (101) and TiO2 (101) for DFT calculation of EOV.Figure 4. CO2 conversion test and selectivity of (a) PtSA/TiO2−x, (b) PtNC/TiO2−x, and (c) PtNP/TiO2−x. (d) Arrhenius plot for the RWGS reaction over the series Pt/TiO2−x catalysts (H2:CO2 = 3:1, 0.1 MPa and 240–390°C). (e) CO2 conversion rates over PtSA/TiO2−x catalysts with different GHSV (H2:CO2 = 3:1; 0.1 MPa and 330°C). (f) RWGS stabilities of the series Pt/TiO2−x catalysts at 330°C. (g) In situ DRIFT spectra of the RWGS reaction over PtSA/TiO2−x. (h) RWGS performance comparison of this work with the reported noble metal catalysts.Xin Kang, Jiancong Liu, Ying Xie, Dongxu Wang, Qihui Liu, Peng Yu, Chungui Tian, Honggang Fu. Pt single atoms in oxygen vacancies boost reverse water-gas shift reaction by enhancing hydrogen spillover. Sci. China Mater. (2024).https://doi.org/10.1007/s40843-024-3011-6
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