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Light-Induced Synergistic Multidefect Sites on TiO2/SiO2 Composites for Catalytic Dehydrogenation
Saputera W.H.a,b, Tahini H.A.c, Sabsabi M.a, Tan T.H.a, Bedford N.M.a, Lovell E.a, Cui Y.a, Hart J.N.a, Friedmann D.a,d, Smith S.C.c, Amal R.a, Scott J.a
a Particles and Catalysis Research Group, School of Chemical Engineering, UNSW, Sydney, 2052, Australia
b Department of Chemical Engineering, Institut Teknologi Bandung, Bandung, 40132, Indonesia
c Integrated Materials Design Laboratory, Research School of Physics and Engineering, Australian National University, Canberra, 2601, Australia
d School of Chemistry, RMIT, Melbourne, 3000, Australia
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© 2019 American Chemical Society.Here, we demonstrate that structural defects can induce catalytic reactivity in simple metal oxides to deliver cost-effective alternatives to noble metal group catalysts. We detail a strategy for introducing multiple defect sites in a binary TiO2-SiO2 composite to invoke synergism for oxygen activation. Hydrogenation and UV light pretreatment were applied to generate two distinct and adjacent defect sites, Ti3+ and silica-based nonbridging oxygen hole centers (NBOHC) – which work in unison to activate oxygen and oxidize formic acid under ambient conditions without light. The hydrogenation step was found to be crucial for rupturing Ti-O-Si bonds while first-principles calculations indicated that Si-doped TiO2 lowered the energy barrier for oxygen activation and formic acid dehydrogenation on the defect sites. Activity lost during the reaction was recoverable by catalyst reillumination. Defective metal oxides represent an appealing prospect in the pursuit of simple and readily accessible catalyst materials.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Ambient conditions,Catalytic dehydrogenation,Catalytic reactivity,First-principles calculation,Nonbridging oxygen hole center,Oxygen activations,Pre-Treatment,TiO2-SiO2[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]defects,dehydrogenation,nonbridging oxygen hole center (NBOHC),oxygen activation,Ti3+,TiO2-SiO2,UV light pretreatment[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text]The work was supported by the Australian Research Council (ARC) under the Laureate Fellowship Scheme-FL140100081. W.H.S. acknowledges the Indonesia Endowment Fund for Education Scholarship (LPDP), Republic of Indonesia for financing his Ph.D. scholarship. The authors acknowledge the use of facilities (XRD, EPR, FTIR, XPS, Raman Spectroscopy) within the UNSW Mark Wainwright Analytical Centre and Dr. Bill Bin Gong for his assistance with the XPS analysis. The authors also acknowledge Dr. David Mitchell from the Electron Microscopy Centre within the Australian Institute for Innovative Materials, based at the University of Wollongong, for his assistance with the HR-HAADF-STEM and HR-TEM imaging. This research used the inner shell spectroscopy (ISS) beamline of the National Synchrotron Light Source II (NSLS-II), a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. We thank Dr. Klaus Attenkofer for assistance with XAS experiments at the ISS beamline at NSLS-II. This research was also undertaken with the assistance of computational resources provided by the Australian Government through National Computational Infrastructure (NCI) under the National Computational Merit Allocation Scheme.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1021/acscatal.8b04891[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]