Wenchao Shangguan,Guoqiang Li,Shidi Gui,Xiaodong Zhang,Sugang Meng,Shifu Chen,Yingxuan Li
Separating photoexcited holes in metallic nanostructure to drive H 2 O oxidation reaction to balance the CO 2 photoreduction reaction is highly desirable, but challenging. The bottleneck lies in the sluggish kinetics of both photoexcited hole transfer and H 2 O oxidation. Herein, this work demonstrates that the in situ reconstruction of n -type wide-bandgap AlOOH-supported Au nanoparticle heterogeneous photocatalyst, triggered by thermal and photothermal cooperative effect during photocatalytic reactions, facilitates the efficient CO 2 photoreduction through optimizing the Au 5 d -band holes separation and H 2 O activation. In situ and ex situ characterizations evidence restructuring at interfaces to form an ultrathin γ-Al 2 O 3 nanolayer (≈2 nm thickness), which optimizes the energy band structure and promotes spontaneous transfer of photoexcited Au 5 d -band holes to the valence band of AlOOH, and prolongs the lifetime of electrons available for CO 2 reduction on Au. Furthermore, hydroxyl vacancies generated during restructuring process are demonstrated to promote H 2 O adsorption and lower the energy barrier for O 2 formation, supplying adequate protons for CO 2 protonation reduction and thereby boosting CO 2 photoreduction efficiency. This study offers valuable insights into the underlying mechanisms of utilizing n -type semiconductors to separate photoexcited d -band holes in metal nanoparticles.
The use of biogas as renewable raw material to produce syngas（H 2 /CO ≈ 2）suitable for direct synthesis of methanol has attracted wide attention, but designing promising catalysts with high activity and stability remains a challenge. The catalytic systems used for this process usually have the characteristics of poor stability and easy carbon deposition. Here, Based on the Ce redox cycle and the strong metal-support interaction (SMSI), we designed and synthesized a series of Ni catalysts (denoted as Ni/CeMgO x /BN) with BN interfacial constraints. The abundant oxygen vacancy of reaction-induced Ce redox cycle endows Ni/CeMgO x /BN with excellent carbon resistance, because the ability to activate CO 2 /H 2 O is significantly enhanced. The CO 2 /H 2 O activation and carbon elimination mechanism were comprehensively characterized by in situ H 2 -TPR/CO 2 /H 2 O-TPSR, in situ CH 4 -TPSR/CO 2 /H 2 O-TPO, and FTIR, etc. Ascribed to the appropriate basicity of CeMgO x , homogeneous Ni dispersion, and strong interaction between Ni ultra-small nano particles (NPs) and CeMgO x /BN, Ni/CeMgO x /BN exhibit higher CO 2 /H 2 O adsorption/activation, higher CH 4 activation/dissociation, compared with another samples, which facilitate the formation of active oxygen species and intermediate coke removal, thus enhance the resistance to coke deposition and sintering. At 750 °C, Ni/CeMgO x /BN exhibit satisfying catalytic activity (CH 4 /CO 2 conversation 92 %/52 %) and superior stability (100 h) with negligible deactivation rates.
Developing photocatalysts with high activity and selectivity remains a significant challenge in the field of CO 2 photoreduction for producing valuable chemical or fuel products under mild conditions. Herein, photonic crystal (PC) GDY-Cu/ZnO was constructed through the in-situ induced growth of graphdiyne (GDY) on PC Cu/ZnO surface via H 2 -reduction for efficient photoreduction of CO 2 to CH 4 . With the aid of photonic crystal structure, PC GDY-Cu/ZnO exhibits a distinctive red-edge slow light region which can significantly improve the utilization efficiency of visible light and intensify photo-catalysis. Additionally, the formed all-solid-state Z-scheme system efficiently accelerates photoelectron migration, facilitating e - /h + separation. Thirdly, the surface GDY, along with the enrich oxygen vacancies generated during H 2 reduction, enhances the adsorption and activation toward CO 2 and H 2 O on PC GDY-Cu/ZnO interface. In consequence, PC GDY-Cu/ZnO demonstrates highly photocatalytic conversion of CO 2 to CH 4 , achieving a CH 4 yield of 33.67 μmol·g −1 ·h −1 with 93.3 % selectivity via slow-light-driven photocatalysis CO 2 reduction. This work provides an efficient strategy to modify ZnO for the efficient photoreduction of CO 2 to CH 4 .
危险品化学品经营许可证（带存储）