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Selective catalytic reduction of NOx by ammonia (NH3‐SCR) was affected by HCl, which was widely present in industrial flue gas. In this study, the SCR performances over MOx‐WO3/TiO2 (MW/Ti, M=Mn, Ce and V) catalysts after HCl treatment were investigated. It was found that HCl poisoning showed inhibition and promotion in NOx conversion over MnW/Ti and CeW/Ti catalysts, respectively. While the SCR activity over VW/Ti catalyst was hardly affected by HCl. Over MnW/Ti catalyst, the rupture of the Mn−O bond by the strong Mn−Cl binding induced the formation of amorphous MnCl2 species. This Cl‐containing species with Mn in a low oxidation state exhibited poorer redox ability and NO activation, resulting in a decrease in low‐temperature SCR activity. However, instead of directly affecting the CeOx and VOx sites, gaseous HCl reacted with NH3 to form NH4Cl species on the surface of CeW/Ti and VW/Ti catalysts. As a result, the SCR activity of VW/Ti catalyst was scarcely influenced by HCl, taking the unchanged redox ability and NH3 adsorption. With a further accumulation of NH4Cl on CeW/Ti catalyst, the NOx conversion at low temperature was evidently enhanced due to the promotion in NO‐to‐NO2 conversion (Fast‐SCR). [ABSTRACT FROM AUTHOR]

Selective catalytic reduction of nitrogen oxides (NOx) with C3H6 (C3H6‐SCR) was investigated over NiO catalysts supported on different metal‐oxides. A NiAlOx mixed oxide phase was formed over NiO/γ‐Al2O3 catalyst, inducing an immediate interaction between NiOx and AlOx species. Such interaction resulted in a charge transfer from Ni to Al site and the formation of Ni species in high oxidation state. In comparison to other NiO‐loaded catalysts, NiO/γ‐Al2O3 catalyst exhibited the highest NOx conversion at temperature higher than 450 °C, but a poor C3H6 oxidation activity due to the decreased nucleophilicity for surface oxygen species. By temperature‐programed NO oxidation, it is indicated that nitrate species were rapidly formed and stably maintained at high temperature over NiO/γ‐Al2O3 catalyst. In situ transient reactions further verified the Langmuir–Hinshelwood mechanism for C3H6‐SCR, where both gaseous NO and C3H6 were adsorbed and activated on catalyst surface and reacted to generate N2. Due to the strong metal‐support interaction over NiO/γ‐Al2O3 catalyst, both nitrate and CxHyOz intermediates were well preserved to attain high C3H6‐SCR activity. [ABSTRACT FROM AUTHOR]

Nitrate, as an important nitrogen source, plays a crucial role in the fields of energy, chemicals, and the environment. Electrocatalytic nitrogen conversion, powered by renewable energy sources, is a viable and promising strategy for the synthesis and conversion of nitrate. In this work, electrocatalytic synthesis and conversion of nitrates associated with five reactions: ammonia oxidation reaction (NH3OR), nitrogen oxidation reaction (N2OR), NO oxidation reaction (NOOR), nitrate reduction reaction (NO3RR), and the electrochemical C-N coupling of CO2 and NO3− (C–N coupling) were reviewed. At present, it is found that most of these reaction processes still suffer from low Faradaic efficiency and product yield. The underlying mechanisms, key steps, and rational catalyst design for these nitrogen electrochemical reactions were summarized. This review aims to provide insights into the fundamentals in the relevant reactions, the development of efficient catalysts, and the advances in the progress of artificial nitrogen cycling processes.Graphical Abstract: Nitrate, as an important nitrogen source, plays a crucial role in the fields of energy, chemicals, and the environment. Electrocatalytic nitrogen conversion, powered by renewable energy sources, is a viable and promising strategy for the synthesis and conversion of nitrate. In this work, electrocatalytic synthesis and conversion of nitrates associated with five reactions: ammonia oxidation reaction (NH3OR), nitrogen oxidation reaction (N2OR), NO oxidation reaction (NOOR), nitrate reduction reaction (NO3RR), and the electrochemical C-N coupling of CO2 and NO3− (C–N coupling) were reviewed. At present, it is found that most of these reaction processes still suffer from low Faradaic efficiency and product yield. The underlying mechanisms, key steps, and rational catalyst design for these nitrogen electrochemical reactions were summarized. This review aims to provide insights into the fundamentals in the relevant reactions, the development of efficient catalysts, and the advances in the progress of artificial nitrogen cycling processes. [ABSTRACT FROM AUTHOR]

A series of Cd-doped NiO catalysts were prepared and tested in the N 2 O catalytic decomposition reaction. In comparison with NiO, it was found that the Cd 0.04 Ni catalyst showed higher N 2 O decomposition activity in the temperature range of 300–450 °C with or without O 2 , and lower activation energy (77.8 kJ mol−1). The incorporation of Cd into the NiO lattice was verified by X-ray diffraction (XRD) patterns and Raman spectra. This led to the distortion of the original NiO structure and weakened the Ni-O bond. X-ray photoelectron spectroscopy (XPS) results showed that compared with NiO and CdO, Cd 0.04 Ni possessed higher Ni2+ and Cd(n+1)+ contents, which might have been induced by the electron transfer behavior between CdO and NiO. A possible mechanism for active site regeneration and O 2 desorption over Cd 0.04 Ni was proposed. The Cd 0.04 Ni catalyst also exhibited good resistance to NO and O 2. [Display omitted] • Catalytic decomposition of N 2 O over NiO was improved by Cd-doping. • Incorporated Cd led to the lattice distortion of NiO and weakened the Ni-O bonds. • Cd 0.04 Ni exhibited unaffected N 2 O decomposition activity with and without O 2. • A possible electron transfer mechanism on Cd 0.04 Ni was proposed. [ABSTRACT FROM AUTHOR]

Efficient internal mixing stands as a pivotal requirement for droplet-based micro-reactors/micro-mixers facilitated by microfluidic systems. Among the various methods for their production, capillary-generated droplets emerge as a notable approach. Understanding the role of coaxiality within coflow microfluidic devices in influencing internal mixing remains a crucial aspect for optimizing these systems. Coaxiality within inserted cylindrical capillaries significantly affects mixing efficiency according to our experimental observations. Through numerical simulations, the intricate mixing dynamics of reagents inside droplet generated via a coflow capillary microfluidic system has been investigated. We demonstrate that coaxiality profoundly impacts the initial distribution of disperse phases within droplets, shaping subsequent internal mixing dynamics. Contrary to previous assumptions, our findings highlight the substantial impact of marginal deviations in coaxiality, around 20%, on optimizing mixing efficiency. This challenges prior beliefs and emphasizes the nuanced role of coaxiality in microfluidic systems. These insights advance our understanding of coaxiality's critical influence on enhancing mixing efficiency within coflow microfluidic devices, paving the way for improved design strategies and applications in diverse scientific fields. [ABSTRACT FROM AUTHOR]

Chlorine species, widely presented in industrial flue gas such as the waste incineration plants, can poison the catalysts and affect the selective catalytic reduction (SCR) performance. In this work, effects of Cl on the SCR performance of V2O5–WO3/TiO2 (VW/Ti) catalysts were investigated by NH4Cl deposition. The results showed that the NOx conversion efficiency at low reaction temperature (< 300 °C) decreased with the loading of NH4Cl after calcination. It was found that instead of causing the chlorination of VW/Ti catalyst the NH4Cl decomposed into volatile Cl species due to the weak V–Cl bonding. Such decomposition reduced significantly the surface non-lattice oxygen species to inhibit NO adsorption and activation, but hardly affected the redox ability and acidity of VW/Ti catalyst. Time–resolved in situ DRIFTs results indicated that NH3 activation and the SCR process predominated by Eley–Rideal mechanism were not influenced with NH4Cl impregnation, while the SCR at low temperature following a Langmuir–Hinshelwood path was limited by the decreased and weaker binding sites for NO activation. [ABSTRACT FROM AUTHOR]

The expansion of offshore wind farms into deeper waters presents economic challenges due to the rising costs of operation and maintenance. To address this issue, the development of targeted opportunistic maintenance strategies for offshore wind farms is crucial. Existing strategies often overlook the interconnections between maintenance activities across wind farms, focusing solely on individual wind farms. However, joint maintenance of wind farms has been acknowledged as an effective approach to reducing maintenance costs at the operational level. This paper introduces an opportunistic maintenance strategy that considers the joint maintenance of two wind farms and establishes reliability thresholds to guide maintenance decisions. Furthermore, the developed maintenance model is improved by incorporating more realistic vessel models and considering various types of maintenance costs. Conclusions can be drawn from a comprehensive analysis of optimization results across multiple scenarios involving maintenance costs, wind farm parameters, and uncertainties. The comparative analysis demonstrates that, in the farthest offshore distance case, the proposed strategy exhibits a reduction in maintenance costs of 15.67% and 4.87% when compared to two traditional strategies, respectively. This effect is further amplified in scenarios where offshore wind farms are located in close proximity to each other and encounter substantial uncertainties. • Developing a novel joint maintenance strategy for two offshore wind farms. • New decision-making structure is established using three decision thresholds. • The strategy is evaluated considering cost, wind farm parameters, and uncertainty. • The proposed strategy saves 15.67% and 4.87% in LCC versus traditional strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • AgCo-g-CN possessed enhanced catalytic decomposition of N 2 O under O 2 compared with Co 3 O 4. • Metallic Ag and higher content of Co2+ were found on AgCo-g-CN by adding g-CN. • Higher contents of Co2+ could play a beneficial role in the enhancement of N 2 O catalytic decomposition. • Metallic Ag improved the O 2 desorption capacity of AgCo-g-CN. Nitrous oxide (N 2 O) has gained increasing attention as an important greenhouse gas and stratospheric-ozone-depleting substance. Catalytic decomposition is considered an effective method for N 2 O abatement. Herein, AgCo-g-CN catalyst prepared by impregnation synthetic procedure was tested for N 2 O catalytic decomposition in the presence of O 2. The catalytic results indicated that full N 2 O conversion was obtained at 400 °C. The enhancement of catalytic activity was mainly derived from the addition of g-CN compared with bare Co 3 O 4 and AgCo. Metallic Ag and higher content of Co2+ were found over the AgCo-g-CN catalyst. By XPS and kinetic analysis, the catalytic performance was correlated with the content of Co2+, the facilitation of Co2+ contents could play a beneficial role in the enhancement of the AgCo-g-CN catalysts. Besides, HRTEM, XPS, and TPx revealed that metallic Ag improved the O 2 desorption capacity of AgCo-g-CN, which is important during the N 2 O catalytic decomposition. By lowering the valence of Co and Ag species, g-CN enhanced the catalytic performance of N 2 O. This study might provide a reference for designing N 2 O decomposition catalysts and potential applications for g-CN in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

The safe and efficient operation of submarine high-voltage cables depends on their thermal performance. Based on the electromagnetic heat coupling and heat transfer theory, the cables' heat dissipation in multi-layered sediments is simulated using FEM. The proposed models are validated by comparing with the results of IEC 60287 and illustrated the limitation of IEC 60287 which ignores convective heat transfer. Further, the width of the cable embedding layers greater than 9 m can promote heat dissipation when the permeability of the cable embedding layer is relatively high, but the effect of depth is less pronounced. Also, the cable temperatures increase with the decrease of sediments thermal conductivity and increase of the buried depth when permeability is below 10−12 m2. The temperature decreases as the permeability increases, the range of decay is between 10% and 55% when the permeability reaches 10−9 m2. The heat dissipation is great when the permeability is greater than 10−11 m2. When the characteristic of the cable embedding layers is different from its upper and lower layers, the high permeability of the upper layers reduces the cable conductor temperature more efficiently than the lower layers. The findings give some reference in improving the transmission efficiency of cables. • The influence of multi-layered sediment characteristics on the thermal performance of submarine cables is analyzed. • The high permeability could help dissipate heat efficiently, the decay of conductor temperature can be up to 40%. • This paper illustrated the limitation of present methods in IEC 60287 which ignores the effect of convective heat transfer. • The submarine cables buried in sands or coarser sediments are better, and the buried depth is as small as possible. • The width of the cable embedding layers greater than 9 m can effectively promote the convective heat dissipation. [ABSTRACT FROM AUTHOR]

The subsea tree acts as an important role in underwater production system. During its installation procedure, hydrodynamic loads significantly affect its dynamic performance. Hence, the drag coefficient of the subsea tree is addressed in detail in the paper by experiment and numerical simulation. Numerical simulation was carried out with finite difference method to get the drag force and drag coefficient. A new experimental method was proposed to conduct an array of model experiments for drag coefficient of subsea tree. The numerical results in drag coefficient were slightly different with experimental results, that was to say, the accuracy and reliability of the experimental data were proved. The drag coefficient is 0.432 in x-direction, 0.479 in y-direction and 0.446 in z-direction, which provide the accurate fundamental hydrodynamic data for underwater production system installation. • Hydrodynamic coefficient plays an important role in hydrodynamic and motion response. • Towing test in the tank can obtain the hydrodynamic data of subsea equipment. • Drag force has a gradual rise with the increase of flow velocity. • Drag coefficient is slightly differ with different flow velocity. [ABSTRACT FROM AUTHOR]