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Developing highly efficient non-noble metal electrocatalysts for the oxygen evolution reaction (OER) at large current densities remains a challenge for water electrolysis. Herein, we developed a novel 3D ternary hybrid electrocatalyst consisting of Fe2O3 strongly coupled with Ni2P/Ni(PO3)2 grown on commercial Ni foam (denoted as Fe2O3@Ni2P/Ni(PO3)2/NF) through a thermal phosphorization reaction. In this 3D hybrid structure, the Fe2O3@Ni2P/Ni(PO3)2 nanoparticles with a length of ∼300 nm and width of ∼200 nm are homogeneously grown on the surface of 3D Ni foam. Owing to the synergistic effect between Fe2O3@Ni2P/Ni(PO3)2/NF and their strong coupling effect, the 3D Fe2O3@Ni2P/Ni(PO3)2/NF hybrid achieves a superior electrocatalytic OER performance at ultra-high current densities in alkaline electrolyte. High catalytic current densities of 500 and 1000 mA cm−2 are reached by applying only potentials of 1.57 and 1.60 V, respectively, which are almost the lowest potentials among all previously reported transition metal (Ni and Fe) based phosphide and phosphate electrocatalysts, and even better than that of the benchmark Ir/C catalyst (1.64 and ＞1.8 V at 100 and 500 mA cm−2). In situ Raman spectroscopy revealed that the NiOOH and FeOOH species were the real active phases in Fe2O3@Ni2P/Ni(PO3)2/NF during the OER process. A two-electrode electrolyzer with Fe2O3@Ni2P/Ni(PO3)2/NF delivers a cell voltage of 1.93, 2.48, and 3.02 V at 100, 500, and 1000 mA cm−2 for overall-water-splitting. [ABSTRACT FROM AUTHOR]

The coliquefaction of coal and polystyrene (PS) in supercritical water (SCW) was carried out in a 50-mL batch stainless steel autoclave reactor, and the effects of the polymer ratio by weight (10–40%), reaction temperature (633.5–703.5 K), and reaction time (30–120 min) were investigated. The main products were analyzed qualitatively by Fourier transform infrared spectroscopy and high-performance liquid chromatography. The results show that polystyrene stimulates coal liquefaction as a hydrogen donor, and the synergistic effects during coliquefaction in SCW were confirmed. The conversion reached a maximum of 62.26% after 60 min at 673.5 K. The phase behavior during coliquefaction was observed in a fused silica capillary reactor using a combined microscope and video recorder system. [ABSTRACT FROM PUBLISHER]

Water transfer from the Qiantang River to the West Lake, Hangzhou City, China, has been performed since 1985 to improve the lake water quality. This study was conducted to assess the water quality and estimate the pollutant fluxes from different sources into the lake to enable better water quality management. Monthly variations in water quality variables, namely chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD), total phosphorus (TP), total nitrogen (TN), ammonium nitrogen (NH-N), and nitrate nitrogen (NO-N), and flow were analyzed for 1-year period from April 2012 to March 2013. The pollutant fluxes into the lake were mainly contributed by the water transferred from the Qiantang River, followed by runoff and rainfall. The results showed that the annual influxes of COD, BOD, TP, TN, NO-N, and NH-N into the lake were 1,595.3, 255.8, 8.2, 576.0, 360.3, and 84.2 t, respectively, while the annual fluxes out of the lake were 2,204.6, 301.8, 7.1, 336.5, 191.6, and 36.1 t, respectively. The annual net flux of pollutants in decreasing order was TN > NO-N > NH-N > TP > BOD > COD, and nitrogen was found to be the major pollutant in the West Lake. It is recommended that the water transferred from the Qiantang River should be treated by chemical precipitation as well as denitrification technology to reduce the nitrogen concentration. [ABSTRACT FROM AUTHOR]

Significance The solubilities of hydrophobic organic compounds (HOCs) in hot compressed water (HCW) were measured using an optically transparent fused silica capillary reactor (FSCR). The total dissolution temperatures of HOCs in HCW were determined visually; the solution homogeneity in the FSCR during HOCs dissolution was checked using Raman spectroscopy. The solubility of 2,4-dichlorotoluene increased linearly with increasing temperature in the range of 266.3-302.4°C. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2721-2725, 2013 [ABSTRACT FROM AUTHOR]

Fe/Bi-nanocrystal phase transformation within BFPCs catalysts contributes to acceleration of electron transfer in Fenton chemistry in the presence of visible light (λ > 420 nm) irradiation. This enhanced system compared to the alike Fenton-like oxidation formed a myriad of HO• radicals outperforms in mineralization rate (>80% on average for varied EOPs), saving H 2 O 2 usage (85%) and reaction time (50%). [Display omitted] • Bismuth ferrite polymorphism composites (BFPCs) driven photo-Fenton system at λ >420 nm. • The LED/BFPCs/H 2 O 2 system show high efficiency with saving H 2 O 2 (85%) and reaction time (50%). • Crystal-phase restructuring in BFPCs for enhancing Fe3+/Fe2+ circulation in Fenton chemistry was observed. • BFPCs crystal micro-structure was evaluated by atomic-resolution HAADF imaging with EDS mapping. • The azoxystrobin (AZX) degradation pathway in LED/BFPCs/H 2 O 2 system is proposed for the first time. Emerging organic pollutants (EOPs), such as azoxystrobin (AZX) fungicide, have been an increasingly serious problem in aquatic environments. Here, a novel Fe/Bi-nanocrystal (bismuth ferrite polymorphism composites, BFPCs) driven a new photo-Fenton system in visible light (λ >420 nm) irradiation (LED/BFPCs/H 2 O 2) remarkably accelerates hydroxyl radical (HO•) formation with excellent efficiencies of both AZX and other 18 EOPs (especially for AZX 100 % degradation rarely reported). The system outperforms in mineralization rate, saving H 2 O 2 usage (85 %) and reaction time (50 %) compared to the alike Fenton-like system. A phenomenon in BFPCs crystal structure observed on the crystal phase transformation from FeO 6 octahedron into FeO 4 tetrahedron that implied/uncovered a new finding of crystal-phase restructuring for enhancing Fe3+/Fe2+ circulation in Fenton chemistry. The stability of crystal structure and chemical composition of BFPCs catalysts was evaluated by HAADF imaging coupling with EDX mapping at atomic level. The mechanism on AZX degradation pathway in LED/BFPCs/H 2 O 2 system is proposed for the first time by monitoring HO• and its source, and intermediates at a control condition. [ABSTRACT FROM AUTHOR]

To ascertain the reaction variables on o -chloroaniline (o -ClA) mineralization, total nitrogen (TN) removal rate, and N-species distribution, o -ClA was subjected to catalytic supercritical water oxidation (CSCWO) in a fused quartz tube reactor (FQTR). The findings demonstrated that when the temperature, reaction time, and excess oxidant were 400 °C, 90 min, and 150%, respectively, the mineralization rate of o -ClA could reach more than 95%. Moreover, potential degradation pathways of o -ClA in supercritical water oxidation (SCWO) was proposed according to the GC-MS results. TN removal rate is significantly impacted by Ru/rGO, despite the fact that its catalytic effect on the mineralization of o -ClA was not particularly noteworthy. Compared with no catalyst, the TN removal rate of o -ClA obviously increased from 44.1% to 90.3% at 400 °C, 10 wt% Ru loading, 90 min and 200% excess oxidant. In addition, N-species distribution in SCWO and CSCWO were also investigated. Results indicated that the Ru/rGO catalyst could accelerate the oxidation of ammonia-N and convert it to nitrate-N, promoting N 2 generation. Finally, the possible N transformation pathway in CSCWO of o -ClA was proposed. As a result, this work offers fundamental information about o -ClA catalytic oxidation removal in the SCWO process. [Display omitted] • CSCWO of o -ClA was investigated in a FQTR coupled with Raman spectroscopy system. • The potential degradation pathways of o -ClA in SCWO was proposed. • Ru/rGO has a significant effect on the removal rate of TN. • Ru/rGO accelerate the oxidation of ammonia-N to nitrate-N, promoting N 2 generation. • Possible nitrogen transformation pathway in CSCWO of o -ClA was proposed. [ABSTRACT FROM AUTHOR]

The reverse water-gas shift (RWGS) reaction is of great significance to convert CO 2 to valuable feedstocks. Reasonable design and preparation of catalysts is necessary to achieve high CO 2 conversion and CO selectivity. In this study, a series of Cu-Al based spinel catalysts were synthesized by coprecipitation-calcination method or A-site doped with active metal (Co, Zn, Mg, and Fe) for the RWGS reaction. The results indicated that the surface oxygen vacancies and crystal structure of CuAl 2 O 4 can be regulated by calcination temperature. Remarkably, the CuAl-800 catalyst exhibits the highest CO 2 conversion rate (62.7 %) with 100 % CO selectivity at 500 °C. Excessive calcination temperatures (> 800 °C) resulted in a well-defined spinel structure, but decreased surface oxygen vacancies and CO 2 conversion rate. At calcination temperatures < 800 °C, surface oxygen vacancies increased, but the formation of CuO impurities which irreversibly converted to Cu 2 O during reduction, decreased catalytic activity. Compared with Zn, Mg and Fe, Co doping can significantly improved the reactivity of CuAl 2 O 4 catalyst in RWGS reaction at 500 °C, increasing the CO 2 conversion rate by 8 % while maintaining 100 % CO selectivity. The main reason is that Co doping not only effectively improves the integrity and stability of spinel structure of CuAl 2 O 4 , but also enhances its ability to dissociate and activate H species through interfacial sites of CuO-O V -Cu X Co 1-X Al 2 O 4 , thus further enhancing its catalytic conversion ability of CO 2 to CO. These results enrich the understanding of surface chemistry of CuAl 2 O 4 spinel and lay an important theory foundation for design of spinel-based catalysts for RWGS reaction. [Display omitted] • The RWGS reaction catalyzed by CuAl 2 O 4 and Cu x Co 1-x Al 2 O 4 was investigated. • CuAl-800 and Cu 0.8 Co 0.2 Al 2 O 4 exhibit the best catalytic performance. • The formation of Cu 2 O deactivated CuAl 2 O 4 during RWGS reaction. • Interfacial site of CuO-O V -Cu X Co 1-X Al 2 O 4 was more stable than CuO-O V -Al 2 O 3 site. • The mechanisms of RWGS reaction catalyzed by CuAl 2 O 4 and Cu x Co 1-x Al 2 O 4 were proposed. [ABSTRACT FROM AUTHOR]

This work developed a new method for measuring the volume expansion of a CO 2 + n -dodecane mixture, using a fused silica capillary cell (FSCC), combined with a heating-cooling stage and a confocal Raman spectrometer. The cell was constructed on the micron scale to reduce the temperature gradient and reagent consumption. The results confirmed the feasibility of this method that using Raman spectra to verify phase equilibrium, a digital camera to record images of the CO 2 + n -dodecane mixture and a micrometer to measure the volume, a section of water (water seal) between n -dodecane and gas phase to prevent n -dodecane from evaporating. It was shown that the volume expansion factor of the mixture increased with pressure going from 1.0 to 10.0 MPa, but decreased as the temperature was raised from 30 to 80 °C. In addition, a positive quadratic relationship ( R 2 > 0.99) was obtained between Raman peak intensity ratio and volume expansion factor, such that more volume expansion factors could be obtained according to the equations with measured Raman peak intensity ratio data. This experiment widens the ranges of temperature and pressure in the measurements of the volume expansion, and provides more volume expansion data for CO 2 -enhanced oil recovery. [ABSTRACT FROM AUTHOR]

High-valent Au(III) complexes have attracted much attention as catalysts in many reactions. Nevertheless Au(III) catalysts suffer from instability of the oxidized metal complexes during preparation and use. Herein, we demonstrated that Au(III) catalysts can be stabilized against reduction to metallic Au 0 by modifying supported-ionic-liquid-phase-stabilized Au(III) catalyst with CuCl 2 . It was found that the that reduced Au 0 could be re-oxidized in situ to Au 3+ species by CuCl 2 during the reaction and further stabilized by the electron transfer from Cu to these active species. When evaluated in the acetylene hydrochlorination reaction, the Au-Cu-IL/AC catalyst displayed an excellent specific activity with the turnover frequency (TOF) as high as 168.5 h −1 and more than 99.8% selectivity for the product, vinyl chloride (VCM). Furthermore, the Au-Cu-IL/AC catalyst demonstrated a stable catalytic performance with a negligible loss of C 2 H 2 conversion after 500 h under typical industrial reaction conditions for acetylene hydrochlorination. Therefore, the findings of this work provide an efficient approach for designing stable high-valent metals for long-term operation, and also pave the way for the application of Au-Cu-IL/AC catalyst in industrial VCM production. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate that the less toxic, relatively safe, and recyclable organic aqua regia (OAR) can be employed as a greener alternative solvent to conventional aqua regia to activate Au/AC catalysts for the hydrochlorination of acetylene. We show that Au-based catalysts prepared with HAuCl 4 as precursor can be prepared initially in water (Au(H 2 O)/AC). Although catalysts prepared from aqueous HAuCl 4 showed poor activity, it can be significantly enhanced by catalyst activation in OAR (Au(H 2 O)/AC(OAR)). In contrast to the catalyst activation procedure using aqua regia (Au(aq)/AC), we demonstrate that the new activation procedure leads to both improved activity and stability of the resulting Au(H 2 O)/AC(OAR) catalyst. Further analyses of X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) show that the variations of Au particle size and chemical state caused by OAR treatment promote Au oxidation and high dispersion. In addition, temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) indicated that the presence of residual sulfur and nitrogen species may help stabilize the cationic Au 3+ species and generate a catalyst less prone to deactivation by increasing the reduction temperature of the Au 3+ species and enhancing the adsorption of hydrogen chloride over the Au(H 2 O)/AC(OAR) catalyst. These results suggest that OAR can be substituted for conventional solvents to activate Au/AC catalysts for the hydrochlorination of acetylene. [ABSTRACT FROM AUTHOR]

Hydrothermal treatment of renewable biomass and organic waste using supercritical water (SCW) is a sustainable, green, and efficient route for achieving energy recovery, chemicals production, and harmless treatment. The reactor is undoubtedly the central arena where various SCW reactions perform. This review is the first to focus on the special topic, i.e., SCW reactors for biomass conversion and waste treatment. All reported reactors have been classified into three groups to discuss their individual merits and demerits, with a particular focus on their advanced aspects, to minimize or overcome their inherent technical problems (corrosion, plugging, safety issues, poor accessibility, and high energy cost). The first group—metallic reactors—includes tank and tube reactors. These are the most commonly used reactors for diverse SCW processes, and can be operated in three modes: batch, semi-batch, and continuous. The second group includes visual reactors, which are the most attractive experimental devices for SCW processes because they enable visual observation and in situ optical detection. These include X-ray/neutron-radiography-based reactors, the diamond anvil cell, sapphire window reactor, fused silica/quartz capillary reactors, and analogous transparent reactors. The last group includes specially designed reactors for different SCW processes geared toward industrial applications, such as reactors for SCW-based hydrolysis, upgrading, gasification, and oxidation. This review provides comprehensive information for the non-expert reader to select a suitable experimental device for fundamental research and discusses diverse advanced concepts for the development of industrial reactors. [Display omitted] • Three categories and 26 subtypes of SCW reactors are comprehensively reviewed. • Metallic tank and tube reactors are universal, reliable, and inexpensive. • Visual reactors enable visual observation and in situ optical detection. • Specially designed reactors are focused on treating real waste and biomass. • Six advanced conceptual recommendations are provided for industrial reactor design. [ABSTRACT FROM AUTHOR]

The solubility of 4-chlorotoluene in subcritical water was measured using an optically transparent fused silica capillary reactor (FSCR). The total dissolution temperature of 4-chlorotoluene in subcritical water was visually determined. The dissolution uniformity of 4-chlorotoluene in subcritical water was confirmed by Raman spectroscopy. The solubility of 4-chlorotoluene linearly increased with increasing temperature in the range 262.3–293.8 °C. The dissolution mechanism of 4-chlorotoluene in subcritical water is proposed based on the Raman spectra of 4-chlorotoluene and water during the dissolution process in the FSCR. [ABSTRACT FROM AUTHOR]

Because of the rapid growth of global population and economic activity, sewage sludge management is a global conundrum. Conventional landfilling and land-farming of sewage sludge receives increasing critiques due to the negative impacts on environmental sustainability and economic viability. Recently, the thermochemical conversion processes have attracted more and more attentions in sewage sludge treatment, which aims to reduce the volume of sewage sludge and recover of value-added energy and materials. However, the thermochemical conversion involves multiple processes and usually requires a high temperature, which brings many challenges to the large-scale application. Therefore, comprehensive reviews of thermochemical conversion of sewage sludge towards enhanced value-added energy and materials recovery is conducted. Firstly, the composition of sewage sludge and its recovery potential are briefly introduced. Then, a unique analysis of thermochemical conversion of sewage sludge towards value-added energy and materials recovery is elucidated with a focus on the challenges. Ideally, approaches for further sewage sludge management should allow achieving both environmental and economic sustainability. In this instance, varied value-added energy (e.g., thermal energy, combustible gases, H 2 -rich gas, and bio-oils) and materials (e.g., biochar-based functional materials and ash to value-added materials) recovery from sewage sludge are analyzed. Meanwhile, the environmental assessment of thermochemical conversion technologies is evaluated. The further perspectives and recommendations are also outlined. These insights provide further perspectives and recommendations for enhanced sewage sludge management. [Display omitted] • Turning sewage sludge to energy and materials via thermochemical towards carbon neutrality. • Challenges in thermochemical conversion of sewage sludge are assessed. • Energy and materials recovery from sewage sludge via thermochemical conversion are elucidated. • Future perspectives and recommendations for enhanced sewage sludge management are discussed. [ABSTRACT FROM AUTHOR]

Photocatalysis using ZnIn 2 S 4 (ZIS) is demonstrated as a highly efficient zero carbon emission technology using solar energy as the only energy input. In this study, flower-like ZIS microspheres in perfect shape has been successfully prepared by a facile hydrothermal route for the effective degradation of sulfamethoxazole (SMX) in the visible light irradiation. The microsphere exhibits a better spherical shape with uniform particle size of 4–5 µm and large petals of ~10 nm thickness. The initial effect of ZIS nanostructure adjustment is by changing the pH value in the hydrothermal process. The experimental results showed that the flower-like ZIS microspheres synthesised via hydrothermal treatment at pH 1.0 over 16 h at 160 °C have a degradation efficiency of over 90% SMX. The reason is ascribed to more efficient charge separation replying on the specific nanostructure with a large interface contact area of ZIS. In addition, the optimally initial pH in sulfamethoxazole (SMX) degradation system at the highest photocatalytic efficiency is 5.0 approximately. The dominant radical species, namely O 2 •−, is demonstrated by using electron paramagnetic resonance technology. This study provides a facile synthesis method for the preparation of highly efficient visible light photocatalysts. [Display omitted] • A facile hydrothermal method can obtain flower-like ZnIn 2 S 4 with large 'petals'. • ZnIn 2 S 4 with high activity is due to efficient charge separation and transfer. • Photogenerated electrons were successfully transformed to reactive oxygen species. • Optimized ZnIn 2 S 4 possesses remarking reusability towards SMX photodegradation. [ABSTRACT FROM AUTHOR]