Following the growth of ZnO clusters on graphite by in situ X-ray Absorption Near-Edge Spectroscopy

Role of Calcination Temperatures of ZrO2 Support on Methanol Synthesis from CO2 Hydrogenation at High Reaction Temperatures over ZnOx/ZrO2 Catalysts

“…The XANES spectrum of the ZnO reference displayed a shoulder at 9663 eV (E 1 ) and a white line at 9668 eV (E 2 ), followed by small peaks at 9680 eV (E 3 ) and 9714 eV (E 4 ). The white line (E 2 ) was assigned to an electron transition from 1s to 4p. , The peak, E 3 was a typical Zn 2+ with its tetrahedral structure and the peak, E 4 was the first extended X-ray absorption fine structure oscillation which was highly related to the first coordination shell . The XANES spectrum of the 15ZnZr-600 catalyst was markedly different to the ZnO reference.…”

“…The white line (E 2 ) was assigned to an electron transition from 1s to 4p. 40,41 The peak, E 3 was a typical Zn 2+ with its tetrahedral structure 42 and the peak, E 4 was the first extended X-ray absorption fine structure oscillation which was highly related to the first coordination shell. 42 The XANES spectrum of the 15ZnZr-600 catalyst was markedly different to the ZnO reference.…”

In Situ Kinetic Observations on Crystal Nucleation and Growth

“…In another example, Morais and co-workers investigated the hydrothermal synthesis of ZnO NPs on graphite support from the mixture solutions of zinc acetate, hexamethylenetetramine (HMT), and diaminopropane (DAP) by in situ X-ray Absorption Near-Edge Spectroscopy (XANES) in combination with XRD and XPS techniques, highlighting the important role of DAP (as an assembling and structure-growth agent) on the growth rate and final morphology of ZnO NPs …”

“…In another example, Morais and co-workers investigated the hydrothermal synthesis of ZnO NPs on graphite support from the mixture solutions of zinc acetate, hexamethylenetetramine (HMT), and diaminopropane (DAP) by in situ X-ray Absorption Near-Edge Spectroscopy (XANES) in combination with XRD and XPS techniques, highlighting the important role of DAP (as an assembling and structure-growth agent) on the growth rate and final morphology of ZnO NPs. 443 Jia and co-workers investigated the interface kinetics in Sncatalyzed growth of wurtzite (WZ) and zinc-blend (ZB) ZnO NWs from Zn 2 SnO 4 under electron beam irradiation at the atomic scale by in situ TEM. 444 As shown in Figure 56, the growth kinetics of WZ and ZB ZnO NWs appeared markedly different in terms of the crystal-droplet interface and the nucleation site as determined by the contact angle ϕ between the seed particle and the ZnO NW is found to be crucial for tuning the NW structure.…”

In situ analysis of the nucleation of O- and Zn-polar ZnO nanowires using synchrotron-based X-ray diffraction

“…50 More recently, Rodrigues et al investigated the homogeneous growth process and its relationship with Zn(II) species by in situ XANES spectroscopy. 51 Hsieh et al further studied the development of ZnO nanostructures during the homogeneous growth process using in situ transmission electron microscopy (TEM), showing the occurrence of two successive steps in the CBD technique. 52 In order to properly address the issue of the heterogeneous nucleation process by in situ Xray techniques, one challenge is to design a dedicated, leak-tight growth cell that is transparent to X-rays and compatible with a growth medium in aqueous solution.…”