Evolution of Anodic Product from Molybdenum Metal in Absolute Ethanol and Humidity Sensing under Ambient Conditions

Authors would like to thank the support from National Natural Science Foundation of China (NSFC) (Nos. 51702264 and 41371275), Fundamental Research Funds for the Central Universities (No. XDJK2017B033), and Research Funding of Southwest University (No. SWU117019). The funding from the Engineering and Physical Sciences Research Council (EPSRC) (under Grant Nos. EP/K022237/1, EP/K036769/1, and EP/M024938/1) is also acknowledged. We also appreciate the funding from the EU COST Action (No. TD1208) for useful exchanges and discussions.Room-temperature nonaqueous synthetic routes turn out to be particularly competitive among all the available liquid-phase synthetic methods for nanometer-sized metal oxides for multiple applications. Microplasma-assisted anodization is employed to prepare soluble and crystalline Mo species in a water-deficient and extraneous ionic-salt-free ethanol electrolyte. The anodization of Mo in absolute ethanol is found to produce Mo oxyethoxide in the liquid ethanol phase, along with a small montage of mixed hexagonal and orthorhombic MoO3 crystals. The evolution of Mo species in solid and liquid phases is characterized to study the crystallization of MoO3 crystal and the formation of blue spherical Mo polyoxometalates (POMs) after extended aging. The addition of water in the suspension delayed the formation of molybdenum blue while hydrogen peroxide induced the precipitation of a dendritic framework of hexagonal MoO3. A thin MoO3 film was produced from the solution and can be used for humidity sensing by the facile conductivity measurement.PostprintPostprintPeer reviewe

Microplasma-assisted electrochemical synthesis of Co3O4 nanoparticles in absolute ethanol for energy applications

The authors thank the Engineering and Physical Sciences Research Council (EPSRC) for funding (EP/K036769/1, EP/K022237/1, EP/M024938/1). The authors would also like to acknowledge the EU COST Action TD1208 for useful exchanges and discussions. CN would like to thank the support from Fundamental Research Funds for the Central Universities (XDJK2017B033) and Research Funding of Southwest University (SWU117019) and Natural Science Foundation of China (NSFC, 51702264; 41371275).Plasma at the gas/liquid interface can promote a complex mixture of reactions in solution and microplasma-assisted direct-current anodic oxidation is an efficient and green process in synthesising nanoscale materials for various applications. In this study, we demonstrated the direct synthesis of crystalline Co3O4 quantum dots, ca. 2-5 nm in size, by direct anodization of Co foil with charge balanced by the microplasma at the flowing-helium/pure-ethanol interface under ambient condition. The anodic oxidation of cobalt in ethanol was analysed after characterising the solution using nuclear magnetic resonance (NMR), light absorption, photoluminescence (PL), and the solid product using X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Using the microplasma with high voltage under ambient condition, ethanol was oxidised to acetate as the charge carrier and the size of Co3O4 quantum dots can be controlled by the limiting current. The quantum dots from this method are well dispersed in ethanol and a dense coating for light absorption and a rectified diode can be processed directly from the suspension. These results reveals that microplasma-assisted anodisation in ethanol is an efficient and green route capable of manufacturing quantum dots at low-temperature and avoiding the use of extraneous ionic salts in electrolyte.PostprintPeer reviewe

Dissimilatory nitrate reduction to ammonium in four Pseudomonas spp. under aerobic conditions

Dissimilatory nitrate reduction to ammonium (DNRA) has an important role in soil nitrogen retention and is considered to be constrained to anaerobic conditions. However, a recent study found that Pseudomonas putida Y-9 is capable of DNRA under aerobic conditions. In this study, four species of Pseudomonas spp. were found to produce ammonium during the nitrite reduction process under aerobic conditions, similar to the Y-9 strain. The detectable ammonium in the culture supernatant during the nitrite reduction process for each of the four strains originated intracellularly. A subsequent 15N isotope experiment showed that these four strains were able to transform 15NO2− to 15NH4+ in 3 h under aerobic conditions. The NirBD sequence in each of the four strains showed high similarity with that in the Y-9 strain (approximately 94.61%). Moreover, the nirBD sequences in the four strains and the Y-9 strain were all similar to those of other Pseudomonas spp., while they were relatively distant in terms of their phylogenetic relationship from those of other genera. Overall, these results suggest that these four strains of Pseudomonas spp. are capable of DNRA under aerobic conditions, which might be attributed to the existence of nirBD

Evaluation and Factor Analysis of Industrial Carbon Emission Efficiency Based on “Green-Technology Efficiency”—The Case of Yangtze River Basin, China

In the context of low-carbon development, effectively improving carbon emission efficiency is an inevitable requirement for achieving sustainable economic and social development. Based on panel data of 11 provinces and municipalities in the Yangtze River Basin (YRB), ranging from 2000 to 2019, this paper uses green-technology efficiency to measure industrial carbon emission efficiency via stochastic frontier analysis (SFA) incorporated with carbon productivity. This provides a comprehensive analytical framework for assessing the carbon emission efficiency, quantitatively measuring the reduction potential, and clarifying the incentive channels. The results are as follows: (1) The industrial carbon emission efficiency (ICEE) of YRB presents an increasing trend. Although differences in emission efficiency among provinces and municipalities are narrowing, their emission efficiency is still prominently imbalanced. (2) The potential for reducing industrial carbon emissions in this region shows an upward-to-downward trend. The decline in such potential of each province and municipality in recent years indicates that further reduction is becoming more difficult. (3) Effective means to improve ICEE are to improve the level of industrialization, promote technological innovation in industrial low-carbonization, and raise industrial productivity. Meanwhile, the significant spatial spillover effect of ICEE further emphasizes the necessity of strengthening the coordination of carbon reduction policies in YRB. The research in this paper adds a new perspective to the evaluation of ICEE and also provides reference and technical support for the government to enhance ICEE and formulate green and sustainable development policies

Modeling Spatial Pattern of Precipitation with GIS and Multivariate Geostatistical Methods in Chongqing Tobacco Planting Region, China

International audiencePrecipitation is important factor affecting vegetation and controlling key ecological processes. In order to quantify spatial patterns of precipitation in Chongqing tobacco planting region, China, under ArcGIS platform, three multivariate geostatistical methods including cokriging, small grid and regression kriging, coupled with auxiliary topographic factors extracted from a 1:100000 DEM were applied to predict spatial distribution of precipitation for January (the least month), June (the richest month) and the whole year. The results showed that cokriging was the best for prediction precipitation of January, which could explain 58% of the total variation. Small grid simulation with IDW interpolation exhibited higher accuracy for both June precipitation and annual precipitation, which explained 72% and 61% of the total variation respectively. Generally, multivariate geostatistics accounted for most of the spatial variability in mean precipitation and especially could exhibit great improvement for estimating precipitation in areas where topography has a major influence on the precipitation

Evaluation and Factor Analysis of Industrial Carbon Emission Efficiency Based on “Green-Technology Efficiency”—The Case of Yangtze River Basin, China

In the context of low-carbon development, effectively improving carbon emission efficiency is an inevitable requirement for achieving sustainable economic and social development. Based on panel data of 11 provinces and municipalities in the Yangtze River Basin (YRB), ranging from 2000 to 2019, this paper uses green-technology efficiency to measure industrial carbon emission efficiency via stochastic frontier analysis (SFA) incorporated with carbon productivity. This provides a comprehensive analytical framework for assessing the carbon emission efficiency, quantitatively measuring the reduction potential, and clarifying the incentive channels. The results are as follows: (1) The industrial carbon emission efficiency (ICEE) of YRB presents an increasing trend. Although differences in emission efficiency among provinces and municipalities are narrowing, their emission efficiency is still prominently imbalanced. (2) The potential for reducing industrial carbon emissions in this region shows an upward-to-downward trend. The decline in such potential of each province and municipality in recent years indicates that further reduction is becoming more difficult. (3) Effective means to improve ICEE are to improve the level of industrialization, promote technological innovation in industrial low-carbonization, and raise industrial productivity. Meanwhile, the significant spatial spillover effect of ICEE further emphasizes the necessity of strengthening the coordination of carbon reduction policies in YRB. The research in this paper adds a new perspective to the evaluation of ICEE and also provides reference and technical support for the government to enhance ICEE and formulate green and sustainable development policies

Low C/N Ratios Promote Dissimilatory Nitrite Reduction to Ammonium in Pseudomonas putida Y-9 under Aerobic Conditions

The biogeochemical consequences of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) have a significant influence on nitrogen (N) cycling in the ecosystem. Many researchers have explored these two pathways in soil and sediment ecosystems under anaerobic conditions. However, limited information is available regarding the influence of external environmental conditions on these two pathways in a well-defined experimental system under aerobic conditions. In this study, the impacts of the external environmental factors (carbon source, C/N ratio, pH, and dissolved oxygen) on nitrite reduction through the denitrification and DNRA routes in Pseudomonas putida Y-9 were studied. Results found that sodium citrate and sodium acetate favored denitrification and DNRA, respectively. Furthermore, neutral pH and aerobic conditions both facilitated DNRA and denitrification. Especially, low C/N ratios motivated the DNRA while high C/N ratios stimulated the denitrification, which was opposite to the observed phenomena under anaerobic conditions

Land Use Efficiency and Total Factor Productivity—Distribution Dynamic Evolution of Rural Living Space in Chongqing, China

Research on the land use efficiency of rural living spaces is at the core of conflicts about current rural land use and ecological environment construction in China. It can be effectively dealt with through the rational and healthy use of rural land, by promoting sustainable development and urban and rural coordination. Building on the foundation of ecosystem metabolism and sustainable development theories, this paper utilizes the Data Envelopment Analysis (DEA) Malmquist productivity index to divide the land use efficiency total factor productivity (LUTFP) into Malmquist–Luenberger technical change (MLTECH) and Malmquist–Luenberger efficiency change (MLEFFCH) from the perspective of scale change, and uses Kernel Function to measure and study the distribution characteristics of the dynamic evolution and land use efficiency (LUE) in different functional and productive areas and living space subsystem. The results show that, in the process of land use, desirable output growth in the Chongqing city rural living space is lower than the undesirable output reduction rate. Rural human settlement and construction management appears to damage the environment. The LUE in the obtained results showcases an obvious agglomeration effect in Chongqing. Also, there is a very significant “match-up” effect between the LUE and economic development level. In addition, the paper also finds that the technical change index and efficiency change index work together in rural living space LUTFP. The results presented in this paper can provide a basis for the optimization of regional development strategies and rural land utilization