Deciphering the Metal-Support Interaction of Au/ZnO Catalyst Induced by H2 and O2 Pretreatment

Regulating the dispersion of CuO over SiO2 surface for selective oxidation of isobutane to tert-butanol

Controlling the highly selective oxidation of CH bonds in alkanes was still a challenge in the oxidation process, especially in oxygen atmospheres. Herein, three CuO/SiO2 catalysts were designed and prepared by regulating the introduction of copper species to achieve the selective oxidation of tertiary C-H of isobutane (i-C4H10) to tert-butanol (TBA). Under the condition of 130 °C and 1.5 h, CuO/SiO2-DP catalyst could achieve 92.7 % O2 conversion and 85.1 % TBA selectivity, and the cycle stability could be maintained. The improvement of catalytic performance could be attributed to the efficient utilization of Cu atoms, which was related to the regulating the formation of copper phyllosilicate and the full utilization of Si-OH on the surface of SiO2 during the catalyst synthesis process. Copper phyllosilicate formed a rich Si-O-Cu unit, enhanced the metal oxide-support interaction, inhibited the growth of copper species, improved the anchoring and dispersion of CuO, and ultimately improved the accessibility of substrate molecules on active CuO (111). In addition, the adsorption configuration of i-C4H10 and O2 on CuO (111) was determined by in-situ FT-IR and DFT, and the existence form of O2 after charge transfer was discussed. The reaction mechanism of i-C4H10 oxidation to TBA was revealed, which provided theoretical guidance for the selective preparation of TBA from i-C4H10 over metal oxides.

Using In situ Transmission Electron Microscopy to Study Strong Metal-Support Interactions in Heterogeneous Catalysis

Precisely controlling the microstructure of supported metal catalysts and regulating metal-support interactions at the atomic level are essential for achieving highly efficient heterogeneous catalysts. Strong metal-support interaction (SMSI) not only stabilizes metal nanoparticles and improves their resistance to sintering but also modulates the electrical interaction between metal species and the support, optimizing the catalytic activity and selectivity. Therefore, understating the formation mechanism of SMSI and its dynamic evolution during the chemical reaction at the atomic scale is crucial for guiding the structural design and performance optimization of supported metal catalysts. Recent advancements in in situ transmission electron microscopy (TEM) have shed new light on these complex phenomena, providing deeper insights into the SMSI dynamics. Here, the research progress of in situ TEM investigation on SMSI in heterogeneous catalysis is systematically reviewed, focusing on the formation dynamics, structural evolution during the catalytic reactions, and regulation methods of SMSI. The significant advantages of in situ TEM technologies for SMSI research are also highlighted. Moreover, the challenges and probable development paths of in situ TEM studies on the SMSI are also provided.

Thermally Stable Oxide-Capsulated Metal Nanoparticles Structure for Strong Metal-Support Interaction via Ultrafast Laser Plasmonic Nanowelding

Strong metal-support interaction (SMSI) has drawn much attention in heterogeneous catalysts due to its stable and excellent catalytic efficiency. However, construction of high-performance oxide-capsulated metal nanostructures meets great challenge in materials thermodynamic compatibility. In this work, dynamically controlled formation of oxide-capsulated metal nanoparticles (NPs) structures is demonstrated by ultrafast laser plasmonic nanowelding. Under the strong localized electromagnetic field interaction, metal (Au) NPs are dragged by an optical force toward oxide NPs (TiO2). Intense energy is simultaneously injected into this heterojunction area, where TiO2 is precisely ablated. With the embedding of metal into oxide, optical force on Au gradually turned from attractive to repulsive due to the varied metal-dielectric environment. Meanwhile, local ablated oxides are redeposited on Au NP. Upon the whole coverage of metal NP, the implantation behavior of metal NP is stopped, resulting in a controlled metal-oxide eccentric structure with capsulated oxide layer thickness ≈0.72-1.30 nm. These oxide-capsulated metal NPs structures can preserve their configurations even after thermal annealing in air at 600 °C for 10 min. This ultrafast laser plasmonic nanowelding can also extend to oxide-capsulated metal nanostructure fabrication with broad materials combinations (e.g., Au/ZnO, Au/MgO, etc.), which shows great potential in designing/constructing nanoscale high-performance catalysts.

Boosting CO2 piezo-reduction via metal-support interactions in Au/ZnO based catalysts

Confronting the challenge of climate change necessitates innovative approaches for the reduction of CO2 emissions. Metal-support interaction has been widely demonstrated to enable greatly improved performances in thermal-catalytic, photocatalytic and electrocatalytic CO2 reduction. However, its applicability and specifically its role in the emerging piezo-electrocatalytic CO2 reduction are unknown, severely hampering the utilizations of piezo-electrocatalysis in CO2 conversion. Herein, by adopting Au particles supported on ZnO (Au/ZnO) as a paradigm, it is found that the metal-support interaction can remarkably improve the separation and transfer of piezo-carriers and enhance CO2 adsorption. As a result, Au/ZnO demonstrates a substantially boosted activity for piezo-electrocatalytic CO2 reduction and the optimal sample exhibits a 37.3% increase in CO yield compared to the pristine ZnO. The integration of metal-support interactions opens a new avenue to the design of advanced piezo-electrocatalysts for CO2 reduction.