Polyethylene terephthalate (PET) hydrogenolysis can produce benzene, toluene, and xylene (BTX), where the selectivity control is challenging. We report a reaction pathway dictated by the Ru ...coordination environment by examining the binding geometries of adsorbates on differently coordinated Ru centers and their evolution during PET hydrogenolysis. A BTX yield of 77 % was obtained using a Ru/TiO
with a Ru coordination number of ca. 5.0 where edge/corner sites are dominant, while more gas and saturated products were formed for Ru/TiO
containing primarily terrace sites. Density functional theory and isotopic labelling revealed that under-coordinated Ru edge sites favor "upright" adsorption of aromatic adsorbates while well-coordinated Ru sites favor "flat-lying" adsorption, where the former mitigates ring hydrogenation and opening. This study demonstrates that reaction pathways can be directed through controlled reactant/intermediate binding via tuning of the Ru coordination environment for efficient conversion of PET to BTX.
China is in a critical air quality management stage. Rapid industrial development and urbanization has resulted in non-ignorable air pollution, which seriously endangers human health. Assessment of ...the health impacts and economic losses of air pollution is essential for the prevention and control policy formulation. Based on ozone (O
) and fine particulate matter concentration (PM
) monitoring data in 331 Chinese cities from 2015 to 2020, this study evaluated the health effects and the corresponding economic losses of O
and PM
pollution on three health endpoints. The ratio of population exposed to O
levels that exceeded the Chinese Ambient Air Quality Standards (CAAQS) increased from 13.35% in 2015 to 14.15% in 2020, which resulted in 133,415 (2015) - 156,173 (2020) all-cause deaths, 88,941 (2015) - 104,051 (2020) cardiovascular deaths, and 28,614 (2015) - 33,456 (2020) respiratory deaths. The ratio of population exposed to PM
levels that exceeded the CAAQS decreased, but in many regions, especially in North China and the Yangtze River Delta, the PM
concentration remained high. By 2020, nearly half of the population in China was still exposed to PM
levels that exceeded the CAAQS, and the corresponding economic losses reached CNY 3.46 and 3.05 billion, respectively. These results improved the understanding of the spatial-temporal variation trends of major air pollutants at city scale in China, and emphasize the continued coordination urgently needed for controlling O
and PM
following the implementation of the 2013 policy to mitigate air pollution to protect human health.
Size effects are a well-documented phenomenon in heterogeneous catalysis, typically attributed to alterations in geometric and electronic properties. In this study, we investigate the influence of ...catalyst size in the preparation of carbon nanotube (CNT) and the hydrogenation of 4,6-dinitroresorcinol (DNR) using Fe2O3 and Pt catalysts, respectively. Various Fe2O3/Al2O3 catalysts were synthesized for CNT growth through catalytic chemical vapor deposition. Our findings reveal a significant influence of Fe2O3 nanoparticle size on the structure and yield of CNT. Specifically, CNT produced with Fe2O3/Al2O3 containing 28% (mass) Fe loading exhibits abundant surface defects, an increased area for metal-particle immobilization, and a high carbon yield. This makes it a promising candidate for DNR hydrogenation. Utilizing this catalyst support, we further investigate the size effects of Pt nanoparticles on DNR hydrogenation. Larger Pt catalysts demonstrate a preference for 4,6-diaminoresorcinol generation at (1 0 0) sites, whereas smaller Pt catalysts are more susceptible to electronic properties. The kinetics insights obtained from this study have the potential to pave the way for the development of more efficient catalysts for both CNT synthesis and DNR hydrogenation.
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•A size-dependent activity in Pt/carbon nanotube (CNT)-catalyzed 4,6-dinitroresorcinol hydrogenation is reported.•Kinetics study reveals that Pt(100) is the dominating catalytically active surface.•The structure and yield of CNT are strongly influenced by the Fe2O3 particle size.
Summary
As a result of the rapidly depleting global resources, continuing climate change and increasing environmental pollution, and the associated growth in customer awareness, improving product ...sustainability has become a global trend. Comprehensive sustainability assessment techniques are needed to assess a product's sustainability performance throughout its entire life cycle. This article presents the Product Sustainability Index (
ProdSI
) methodology and its application. This methodology is metrics based and provides a comprehensive assessment of the overall product sustainability throughout its total life cycle, covering the four life cycle stages: pre‐manufacturing; manufacturing; use; and postuse. In this article, first the fundamentals of sustainable manufacturing and product sustainability assessment (PSA) are presented, followed by a review of existing PSA methodologies. Major product sustainability elements that are used to define product sustainability clusters and individual sustainability metrics are then presented. Finally, the
ProdSI
methodology for PSA, which follows a hierarchical approach for sustainability metrics identification and overall PSA, is introduced. The application of the methodology is demonstrated in a numerical example of
ProdSI
evaluation for two generations of a consumer electronics component.
Hand, foot, and mouth disease (HFMD), predominantly occurs among infants and children. Previous studies have shown that suitable, stable temperatures favor HFMD virus reproduction; however, ...temperature fluctuations also affect virus transmission, and there are, so far, no studies concerning the association between such fluctuations and the incidence of HFMD. The objective of this study was to map the spatial-temporal distribution of HFMD incidence and quantify the long-term effects of temperature fluctuations on HFMD incidence in children. HFMD cases in children under five, from January 2009 to December 2013, in Beijing, Tianjin, and Hebei provinces of China, were used in this study. The GeoDetector and Bayesian space-time hierarchy models were employed to explore the spatial-temporal association between temperature fluctuations and HFMD incidence. The results indicate that HFMD incidence had significant spatial stratified heterogeneity (GeoDetector q-statistic = 0.83, p < 0.05), and that areas with higher risk mainly appeared in metropolises and their adjacent regions. HFMD transmission was negatively associated with temperature fluctuations. A 1 °C increase in the standard deviation of maximum and minimum temperatures was associated with decreases of 8.22% and 11.87% in the risk of HFMD incidence, respectively. The study suggests that large temperature fluctuations affect virus growth or multiplication, thereby inhibiting the activity of the virus and potentially even leading to its extinction, and consequently affecting the spatial-temporal distribution of HFMD. The findings can serve as a reference for the practical control of this disease and offer help in the rational allocation of medical resources.
Abstract
Methyl methacrylate (MMA) is an important monomer for the production of acrylic plastics and polymer dispersions. In this study, we demonstrate a strategy to synergize the electronic and ...geometric effects of the Au/CeO
2
catalyst, achieving three orders of magnitude improvement in reaction rate for the oxidative esterification of methacrolein to MMA. The electronic properties of Au in terms of the valence electron population of 5d states are decoupled from the redox ability and acid–base properties of catalyst support as the main cause for the significant increase in the specific activity of the active site. Moreover, the Au edge site is identified as the main active site for this reaction, whose number reaches the maximum for the 1.6 nm‐sized Au particles. Hence, the synergism between the electronic (lower valence electron population of 5d states) and geometric (more edge active sites) promotions of the Au‐10/CeO
2
catalyst contributes to the highest catalytic activity.
To investigate the influence of different burial conditions on the seepage characteristics of loose sandstone in the leaching mining of sandstone uranium ore, this study applied different ground ...pressures and water pressures to rock samples at different burial depths to alter the rock's seepage characteristics. The permeability, pore distribution, and particle distribution characteristic parameters were determined, and the results showed that at the same burial depth, ground pressure had a greater effect on the reduction in permeability than water pressure. The patterns and mechanisms are as follows: under the influence of ground pressure, increasing the burial depth compresses the pores in the rock samples, decreases the proportion of effective permeable pores, and causes particle fragmentation, which blocks pore channels, resulting in a decrease in permeability. Under the influence of water pressure, increasing the burial depth expands the pores but also causes hard clay particles to decompose and block pore channels. As the burial depth increases, the particles eventually decompose completely, and the permeability initially decreases and then increases. In this experiment, the relationships between permeability and the proportion of pores larger than 0.15 ㎛ and the proportion of particles smaller than 59 ㎛ were found to be the most significant.
Epidemiological studies reported that ozone (O
) is associated with cardiovascular diseases. However, only few of these studies examined the impact of multiple O
indicators on cardiovascular hospital ...admissions. This study aimed to explore and compare the impacts of different O
indicators on cardiovascular hospital admissions in Guangzhou, China. Based upon the data on daily cardiovascular hospital admissions, air pollution, and meteorological factors in Guangzhou from 2014 to 2018, a time-stratified case-crossover design model was used to analyze the associations between different O
indicators and cardiovascular hospital admissions. Moreover, the sensitivities of different age and gender groups were analyzed for the whole year and different seasons (i.e., warm and cold). During the warm season, for the single-pollutant model, the odds ratio (OR) value of cardiovascular hospital admissions was 1.0067 (95% confidence interval (CI): 1.0037, 1.0098) for every IQR increase in MDA8 O
at a lag of five days. The effect of O
on people over 60 year was stronger than that on the 15-60 years age group. Females were more sensitive than males to O
exposure. These results provided valuable references for further scientific research and environmental improvement in Guangzhou. Given that short-term O
exposure poses a threat to human health, the government should therefore pay attention to prevention and control policies to reduce and eliminate O
pollution and protect human health.
Support effects play a pivotal role in most heterogeneous catalysts, and understanding the underlying catalytic mechanism is crucial for guiding catalyst design and optimizing performance. In this ...study, we conduct a kinetics and mechanistic investigation into the support effects of Cu catalysts in hydrogen combustion by comparing reducible and nonreducible supports. Multiple characterization techniques are employed to comprehend the support effects, with the reducible support and low-valence Cu species highlighted for the most active Cu/ZrO2 catalyst. A redox-based kinetics strategy is further proposed by decoupling the reduction step and oxidation step. The as-obtained reduction and oxidation rate diagram indicates a significantly enhanced reduction rate for the reducible supported catalyst, attributed to the abundant surface oxygen vacancy for the generation of hydroxyl intermediates. These efforts aim to develop more efficient kinetics-based techniques for unraveling the nature of support effects, thereby offering a rational approach to designing highly active catalysts.
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•A redox-based strategy is developed to decipher the support effects of Cu catalysts•The reducible support and low-valence Cu species promote catalytic hydrogen combustion•A reduction and oxidation rate diagram is established to guide catalyst design
Understanding the catalytic mechanism of support effects is crucial for tunable catalysis. Here, Zhang et al. propose a redox-based kinetics strategy by decoupling the reduction step and oxidation step to highlight the important roles of low-valence Cu species and oxygen vacancies in Cu catalysts for catalytic hydrogen combustion.
Typhoons are an environmental threat that mainly affects coastal regions worldwide. The interactive effects of natural and socioeconomic factors on the losses caused by typhoon disasters need further ...examination. In this study, GeoDetector was used to quantify the determinant powers of natural and socioeconomic factors and their interactive effects on the rate of house collapse in Guangdong and Guangxi Provinces of southeast China caused by Typhoon Mangkhut in 2018. We further identify the dominant factors that influenced the disaster losses. The local indicators of spatial association method was then introduced to explain the spatial heterogeneity of the disaster losses under the influence of the dominant factor. The results indicate that both natural and socioeconomic factors significantly affected the house collapse rate. The maximum precipitation was the dominant factor, with a
q
value of 0.21, followed by slope and elevation, with
q
values of 0.17 and 0.13, respectively. Population density and per capita gross domestic product had
q
values of 0.15 and 0.13, respectively. Among all of the interactive effects of the influencing factors, the interactive effect of elevation and the ratio of brick-wood houses had the greatest influence (
q
= 0.63) on the house collapse rate. These results can contribute to the formulation of more specific safety and property protection policies.
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