Curtin University

About: Curtin University is a education organization based out in Perth, Western Australia, Australia. It is known for research contribution in the topics: Population & Zircon. The organization has 14257 authors who have published 48997 publications receiving 1336531 citations. The organization is also known as: WAIT & Western Australian Institute of Technology.

Sulfur and nitrogen co-doped graphene for metal-free catalytic oxidation reactions

Abstract: S ulfur and nitrogen co-doped reduced graphene oxide (rGO) is synthesized by a facile method and demonstrated remarkably enhanced activities in metal-free activation of peroxymonosulfate (PMS) for catalytic oxidation of phenol. Based on fi rst-order kinetic model, S‐N co-doped rGO (SNG) presents an apparent reaction rate constant of 0.043 ± 0.002 min −1 , which is 86.6, 22.8, 19.7, and 4.5-fold as high as that over graphene oxide (GO), rGO, S-doped rGO (S-rGO), and N-doped rGO (N-rGO), respectively. A variety of characterization techniques and density functional theory calculations are employed to investigate the synergistic effect of sulfur and nitrogen co-doping. Co-doping of rGO at an optimal sulfur loading can effectively break the inertness of carbon systems, activate the sp 2 -hybridized carbon lattice and facilitate the electron transfer from covalent graphene sheets for PMS activation. Moreover, both electron paramagnetic resonance (EPR) spectroscopy and classical quenching tests are employed to investigate the generation and evolution of reactive radicals on the SNG sample for phenol catalytic oxidation. This study presents a novel metal-free catalyst for green remediation of organic pollutants in water.

Occurrence of radical and nonradical pathways from carbocatalysts for aqueous and nonaqueous catalytic oxidation

Abstract: Metal-free activation of superoxides provides an efficient and environmentally benign strategy for heterogeneous catalytic oxidation. In this study, nanocarbons with varying carbon-conjugation structures and functional groups were investigated for peroxymonosulfate (PMS) activation. It was discovered that radical and nonradical oxidations could occur on different carbocatalysts depending on the carbon structure. Radical oxidation occurs exclusively on MWCNTs and CMK-3, similar to a metal oxide, MnO2. Both radical and nonradical oxidations are very pronounced in nanodiamond (AND-900)/PMS whilst nonradical oxidation is dominated in reduced graphene oxide (rGO-900)/PMS. Density functional theory (DFT) calculations were employed to explore the PMS adsorption and O O bond activation on the different carbon configurations for an in-depth probe of the activation mechanism. The intact sp2-conjugated π system in MWCNTs and electron-rich ketonic groups (as Lewis basic sites) in CMK-3 can stimulate PMS dissociation to generate SO4 − and OH, similar to metal-based catalysts. However, the defective edges at the boundary of carbon network are able to facilitate the organic degradation without generation of the reactive radicals, which is well supported by both experiments and the DFT calculation. The emerging nonradical oxidation induced by the carbocatalysis is superior to the radical oxidation on most metal oxides for effective degradation of various organics. The influences of solution pH, various anions (H2PO42−, HCO3− and Cl−) and background organic matters (humic acid) on the nonradical oxidation were further evaluated. The nonradical oxidation on carbocatalysts can be utilized as a green and effective oxidation strategy for aqueous environmental remediation and nonaqueous phase oxidation.

Magmatic and metamorphic events during the early Paleozoic Wuyi-Yunkai orogeny, southeastern South China: New age constraints and pressure-temperature conditions

Abstract: The early Paleozoic Wuyi-Yunkai orogen in South China is a major orogenic belt in East Asia that formed at a similar time as the classic Caledonian orogeny in Europe. Despite the possibility of its being one of the few examples of intraplate orogenesis in the world, details about the orogen remain poorly defined. In this study, we provide age constraints on metamorphic and magmatic events in the eastern segment of the orogen, and the protoliths of the amphibolite-facies metamorphic rocks found there. By combining previous work with our new metamorphic and petrogenetic analyses, we present the following findings: (1) the Wuyi-Yunkai orogeny occurred between mid-Ordovician (>460 Ma) and earliest Devonian (ca. 415 Ma) time; (2) amphibolite-facies metamorphism in the eastern Wuyi-Yunkai orogen occurred between ca. 460 and 445 Ma, whereas cooling below 500–300 °C occurred by ca. 420 Ma; (3) the orogen exhibits a clockwise pressure-temperature ( P - T ) path and a maximum pressure of >8 kbar, indicating crustal thickening during the orogeny; (4) protoliths of the high-grade metamorphic rocks in the eastern segment of the orogen were dominantly Neoproterozoic (840–720 Ma) volcanic and volcaniclastic rift successions and younger deposits formed in a failed rift, and Paleoproterozoic rocks account for only a small proportion of the outcrops; and (5) the analyzed granites indicate a mixed source of Paleoproterozoic basement and Neoproterozoic continental rift rocks, with elevated melt temperatures of >800 °C, which are interpreted as reflecting dehydration melting of basin sediments taken to below midcrustal levels.

Recent Progress in Metal-Organic Frameworks for Applications in Electrocatalytic and Photocatalytic Water Splitting.

Abstract: The development of clean and renewable energy materials as alternatives to fossil fuels is foreseen as a potential solution to the crucial problems of environmental pollution and energy shortages. Hydrogen is an ideal energy material for the future, and water splitting using solar/electrical energy is one way to generate hydrogen. Metal-organic frameworks (MOFs) are a class of porous materials with unique properties that have received rapidly growing attention in recent years for applications in water splitting due to their remarkable design flexibility, ultra-large surface-to-volume ratios and tunable pore channels. This review focuses on recent progress in the application of MOFs in electrocatalytic and photocatalytic water splitting for hydrogen generation, including both oxygen and hydrogen evolution. It starts with the fundamentals of electrocatalytic and photocatalytic water splitting and the related factors to determine the catalytic activity. The recent progress in the exploitation of MOFs for water splitting is then summarized, and strategies for designing MOF-based catalysts for electrocatalytic and photocatalytic water splitting are presented. Finally, major challenges in the field of water splitting are highlighted, and some perspectives of MOF-based catalysts for water splitting are proposed.