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Two-dimensional (2D) tungsten disulfide (WS2) nanoflakes were synthesised and hybridised with carbon dots (CDs) using a facile two-step method of exfoliation of bulk tungsten disulphide followed by microwave irradiation of nanoflakes in a solution of citric acid. Physicochemical characterisation indicated that the hybrid consists of graphitic carbon dots with diameters of approximately 2–5 nm, attached to monolayer tungsten disulphide via electrostatic attraction forces. This synthesised hybrid material was investigated for photocatalytic applications. We found that within one hour approximately 30% more of the model organic dye was photodegraded by the hybrid material compared with the pristine 2D WS2. This enhancement was associated to the affinity of the CDs to the organic dye rather than heterojunctioning. Comparisons of the photocatalytic efficacy of this hybrid material with those of recently reported 2D transition metal dichalcogenides and their hybrids showed a significantly higher turnover frequency. Additionally, the presented microwave based synthesis method for developing hybrids of 2D WS2 and CDs, without making significant changes to the base 2D crystal structure and its surface chemistry, has not been demonstrated before. Altogether, the hybrid 2D material provides great potential for photocatalysis applications. [ABSTRACT FROM AUTHOR]

Over the past decade, three technologies, high throughput studies, multiscale modelling (MSM) and self-repair, have entered the field of corrosion science. MSM links processes from 106 to 10−7 m and allows an understanding of how metal protection systems interact with the environment and with surface electrochemical processes. Potentially MSM has the ability to accurately predict component life and so permit virtual design. In virtual design, a huge range of possible design (including molecular designs) can be assessed on a PC before selecting the best performing inhibitor for a specific application. High throughput experimentation permits many tests to be undertaken at one time. As well as allowing a huge range of inhibitors to be tested under a variety of conditions, it allows the inhibitors of the one family with subtly different molecular configurations to be tested. Self-repair is based on the principle that no matter how well we design and construct a material, it will always develop defects and thus the safest way to design is to build in agents that can cause the material to repair itself. These materials by themselves can hasten our material development and provide more reliable materials; however, if combined synergistically, they will permit radically new materials with tailored functionalities to be developed. [ABSTRACT FROM AUTHOR]

Steel coupons were exposed to a supercritical carbon dioxide (CO2) environment in which water contamination was deliberately added over the range from 100 ppmw to 50,000 ppmw. Exposure was carried out in a laboratory scale autoclave at 8 MPa and 40°C for 7 days. Contaminant water in CO2 permits the speciation of carbonic acid (H2CO3), which can itself be a threat to durability, but also permit further contaminants to segregate to the aqueous acid phase. A systematic investigation of corrosion in supercritical CO2 over a range of water concentrations is lacking in the literature, despite being a significant elementary issue. Herein, weight-loss tests were performed, and subsequent scanning electron microscopy suggested all specimens displayed some extent of corrosion. The main corrosion mechanism observed was uniform corrosion. Supplementary optical profilometry suggested that water concentration has a small effect on any pitting corrosion that occurred. In general, increased mass loss was observed with an increase in water concentration beyond N 1,000 ppmw H2O, concomitant with a rate of change in the H2CO3 concentration. [ABSTRACT FROM AUTHOR]

A database was constructed from tests in aqueous electrolytes simulating the damage that may occur to ferrous transport pipelines in the carbon capture and storage (CCS) process. Temperature and concentrations of carbonic acid (H2CO3), sulfuric acid (H2SO4). hydrochloric acid (HCl), nitric acid (HNO3), sodium nitrate (NaNO3), sodium sulfate (Na2SO4), and sodium chloride (NaCl) were varied; the potentiodynamic polarization response, along with physical damage from exposure, was measured. Sensitivity analysis was conducted via generation of fuzzy curves, and a neural network model also was developed. A correlation between corrosion current (icorr) and exposure tests (measured in the form of weight and thickness loss) was observed; however, the key outcome of the work is the presentation of a model that captures corrosion rate as a function of environments relevant to (CCS) pipeline, revealing the extent of the threat and the variables of interest. [ABSTRACT FROM AUTHOR]

This paper outlines how a corrosion map of zinc was developed for Abu-Dhabi. It presents inputs into the model being databases of RH, rainfall, salt deposition and time of wetness and explains how these inputs are combined to product the corrosion map of Abu Dhabi. It is found that although the corrosion rate generally falls with distance from the Arabian Gulf, corrosion rates in the hinterland of the central coast and in the Hajar Mountains are higher than would be expected from a simple dependence on distance from the coast. The higher corrosion rates around the central coast are associated with the extremely low rainfall while those in the Hajar Mountains may be associated with the transport of airborne salinity from the Gulf of Oman. In general, the corrosion rates in Abu Dhabi are much higher than observed at sites in Australia and South East Asia with similar levels of airborne salinity which is attributed to the much higher quantities of salt that are retained on metal surfaces in Abu Dhabi (relative to Australia) due to the fact that rain washing events, which are frequent and effective in Australia, are very infrequent in Abu Dhabi. [ABSTRACT FROM AUTHOR]