Self-optimizing, highly surface-active layered metal dichalcogenide catalysts for hydrogen evolution

Low-cost, layered transition-metal dichalcogenides (MX_2) based on molybdenum and tungsten have attracted substantial interest as alternative catalysts for the hydrogen evolution reaction (HER). These materials have high intrinsic per-site HER activity; however, a significant challenge is the limited density of active sites, which are concentrated at the layer edges. Here we unravel electronic factors underlying catalytic activity on MX_2 surfaces, and leverage the understanding to report group-5 MX_2 (H-TaS_2 and H-NbS_2) electrocatalysts whose performance instead mainly derives from highly active basal-plane sites, as suggested by our first-principles calculations and performance comparisons with edge-active counterparts. Beyond high catalytic activity, they are found to exhibit an unusual ability to optimize their morphology for enhanced charge transfer and accessibility of active sites as the HER proceeds, offering a practical advantage for scalable processing. The catalysts reach 10 mA cm^(−2) current density at an overpotential of ∼50–60 mV with a loading of 10–55 μg cm^(−2), surpassing other reported MX2 candidates without any performance-enhancing additives

Self-optimizing, highly surface-active layered metal dichalcogenide catalysts for hydrogen evolution

Low-cost, layered transition-metal dichalcogenides (MX_2) based on molybdenum and tungsten have attracted substantial interest as alternative catalysts for the hydrogen evolution reaction (HER). These materials have high intrinsic per-site HER activity; however, a significant challenge is the limited density of active sites, which are concentrated at the layer edges. Here we unravel electronic factors underlying catalytic activity on MX_2 surfaces, and leverage the understanding to report group-5 MX_2 (H-TaS_2 and H-NbS_2) electrocatalysts whose performance instead mainly derives from highly active basal-plane sites, as suggested by our first-principles calculations and performance comparisons with edge-active counterparts. Beyond high catalytic activity, they are found to exhibit an unusual ability to optimize their morphology for enhanced charge transfer and accessibility of active sites as the HER proceeds, offering a practical advantage for scalable processing. The catalysts reach 10 mA cm^(−2) current density at an overpotential of ∼50–60 mV with a loading of 10–55 μg cm^(−2), surpassing other reported MX2 candidates without any performance-enhancing additives

Research progress of oil evaporation and vapor diffusion for traceability of carbon emissions from storage tanks

Oil evaporation and vapor diffusion from storage tanks will have adverse effects on atmospheric environment, social economy and the safety of tank farm. In this study, the current status and achievement of the researches on oil evaporation and vapor diffusion were summarized in terms of theoretical analysis, experimental research and numerical simulation for tracing carbon emission from storage tanks. Specifically, the potential mechanism of vapor-liquid phase change, mass transfer of oil vapor in the tank gas space, and vapor diffusion were revealed through theoretical analysis. Meanwhile, the field test and wind tunnel experiment were reviewed, which show that most experimental researches are performed in the aspects of temperature variation characteristics of crude oil in tanks, oil vapor emission during vehicle and ship loading, and dynamic structural change of storage tanks. In addition, simulation methods like Direct Numerical Simulation (DNS), Reynolds Average Navier-Stokes (RANS), and Large Eddy Simulation (LES) were used to analyze the vapor-liquid mass transfer, dynamic tracing of oil-gas interface and the process of vapor diffusion and flow under the coupling of different factors, which could trace diffused substances in a wide range with lower costs and shorter time. Finally, based on the low-carbon development demand of oil and gas industry, suggestions and prospects for oil evaporation and vapor diffusion in storage tanks were put forward with the expectation to maximize the comprehensive benefits of environmental protection

Corporate Carbon Information Disclosure and Financing Costs: The Moderating Effect of Sustainable Development

With the Global Reporting Initiative (a provider of the global best practice for impact reporting) systematically helping parties to understand and exchange issues such as climate change and formulating authoritative sustainability reporting guidelines, corporate sustainable development is becoming more and more critical for companies. Moreover, corporate carbon information disclosure has the potential to promote corporate financing after the Green Climate Fund has been playing their part in climate finance. Previous studies focused more on the cost of equity. Considering the volatility of the capital market, the cost of equity financing is more unstable and complex. This study limited the financing cost to the cost of debt, took Chinese listed companies from 2009 to 2021 as a research sample, and explored the relationship between corporate carbon information disclosure, sustainable development, and financing costs. This study adopted fixed-effects (within) regression or random-effects GLS regression (defined through the Breusch and Pagan Lagrange multiplier test for random effects and the Hausman test) as estimation methods to control individual effects and endogenous problems brought by time. At the same time, the model was modified when there was heteroscedasticity and autocorrelation accordingly. The results show that the more carbon information disclosure, the lower the financing cost; sustainable development weakens the inhibitory effect of carbon information disclosure on financing costs. This study affirms the financing value of reducing information asymmetry, and found that sustainable development (internal growth capacity) may increase the cost of debt. The stronger the sustainable development is, the more financing needs may be, thus raising the cost of debt. This study not only implies that creditors may attach importance to the value of carbon information disclosure at the time of borrowing, but also provides theoretical evidence for the government or securities regulators to speed up the mandatory carbon information disclosure

Corporate Carbon Information Disclosure and Financing Costs: The Moderating Effect of Sustainable Development

With the Global Reporting Initiative (a provider of the global best practice for impact reporting) systematically helping parties to understand and exchange issues such as climate change and formulating authoritative sustainability reporting guidelines, corporate sustainable development is becoming more and more critical for companies. Moreover, corporate carbon information disclosure has the potential to promote corporate financing after the Green Climate Fund has been playing their part in climate finance. Previous studies focused more on the cost of equity. Considering the volatility of the capital market, the cost of equity financing is more unstable and complex. This study limited the financing cost to the cost of debt, took Chinese listed companies from 2009 to 2021 as a research sample, and explored the relationship between corporate carbon information disclosure, sustainable development, and financing costs. This study adopted fixed-effects (within) regression or random-effects GLS regression (defined through the Breusch and Pagan Lagrange multiplier test for random effects and the Hausman test) as estimation methods to control individual effects and endogenous problems brought by time. At the same time, the model was modified when there was heteroscedasticity and autocorrelation accordingly. The results show that the more carbon information disclosure, the lower the financing cost; sustainable development weakens the inhibitory effect of carbon information disclosure on financing costs. This study affirms the financing value of reducing information asymmetry, and found that sustainable development (internal growth capacity) may increase the cost of debt. The stronger the sustainable development is, the more financing needs may be, thus raising the cost of debt. This study not only implies that creditors may attach importance to the value of carbon information disclosure at the time of borrowing, but also provides theoretical evidence for the government or securities regulators to speed up the mandatory carbon information disclosure

Adsorption capacity and thermal effect of adsorbents for oil vapor with humidity

As the standards for emissions of organic waste gas become increasingly strict, the competitive adsorption of water vapor and organic waste gas is becoming the hot spot of research on treatment of organic waste gas. Therefore, three adsorbents (AdsFOV-1, AdsFOV-2 and AdsFOV-3) were used for the research, and their adsorption capacity and thermal effect were investigated through the static adsorption to the vapors of n-hexane, gasoline and water after structural characterization. In addition, dynamic adsorption experiments were performed with the vapors of n-hexane and gasoline under different relative humidity conditions, so as to study the influence of relative humidity on adsorption effect and temperature rising curve, as well as the stability of cyclic adsorption. Meanwhile, the kinetics behavior of the adsorption process was judged by kinetic fitting. The results show that: the adsorption capacity of the three adsorbents to the vapors of n-hexane and gasoline decreases with the increasing of relative humidity, but the thermal effect of adsorption becomes more obvious. Besides, AdsFOV-1 and AdsFOV-2 have good cyclic adsorption performances, specifically, when the inlet vapor mass concentration is set to 25 g/m3, the outlet vapor mass concentration of the adsorption tower can meet the emission requirements of less than 80 mg/m3. Further, the adsorption kinetics behavior of the three adsorbents on the vapor of n-hexane is consistent with the Bangham dynamic equation, which means the adsorption rate is mainly controlled by the pore diffusion. In general, the research results could provide theoretical basis for the treatment of industrial organic waste gas with high humidity

Vertically Aligned Carbon Nanotubes/Graphene Hybrid Electrode as a TCO- and Pt-Free Flexible Cathode for Application in Solar Cells

Dye-sensitized solar cells (DSSCs) are an emerging photovoltaic technology with both low costs and good efficiency. However, the cathode used in most DSSCs is fluorine-doped tin oxide glass coated with a Pt film, which is both expensive and brittle and therefore limits the flexibility and large-scale implementation of this promising technology. We report here work which showed that flexible, seamlessly covalently bonded, three-dimensional vertically aligned few-walled carbon nanotubes (VAFWCNTs)/graphene on metal foil can act as a novel cathode free from transparent conducting oxide and Pt for application in DSSCs. This cathode has a lower charge transfer resistance and lower contact resistance between the catalyst and the substrate than the conventional combination in a brittle Pt/fluorine-doped tin oxide cathode. The covalently bonded graphene and VAFWCNTs ensure excellent electron transport through the electrode and the large surface area of the hybrid carbon materials rivals the catalytic capability of the Pt analogue. DSSCs utilizing this flexible VAFWCNTs/graphene hybrid cathode outperformed the Pt-based cells in both rigid (8.2% vs. 6.4%) and flexible (3.9% vs. 3.4%) assemblies. The VAFWCNTs/graphene on metal foil combination is a novel, inexpensive, high-performance, flexible cathode for application in solar cells

Transcriptome and Network Analyses Reveal the Gene Set Involved in PST Accumulation and Responses to Toxic Alexandrium minutum Exposure in the Gills of Chlamys farreri

Bivalve molluscs are filter-feeding organisms that can accumulate paralytic shellfish toxins (PST) through ingesting toxic marine dinoflagellates. While the effects of PST accumulation upon the physiology of bivalves have been documented, the underlying molecular mechanism remains poorly understood. In this study, transcriptomic analysis was performed in the gills of Zhikong scallop (Chlamys farreri) after 1, 3, 5, 10, and 15 day(s) exposure of PST-producing dinoflagellate Alexandrium minutum. Higher numbers of differentially expressed genes (DEGs) were detected at day 1 (1538) and day 15 (989) than that at day 3 (77), day 5 (82), and day 10 (80) after exposure, and most of the DEGs were only regulated at day 1 or day 15, highlighting different response mechanisms of scallop to PST-producing dinoflagellate at different stages of exposure. Functional enrichment results suggested that PST exposure induced the alterations of nervous system development processes and the activation of xenobiotic metabolism and substance transport processes at the acute and chronic stages of exposure, respectively, while the immune functions were inhibited by PST and might ultimately cause the activation of apoptosis. Furthermore, a weighted gene co-expression network was constructed, and ten responsive modules for toxic algae exposure were identified, among which the yellow module was found to be significantly correlated with PST content. Most of the hub genes in the yellow module were annotated as solute carriers (SLCs) with eight being OCTN1s, implying their dominant roles in regulating PST accumulation in scallop gills. Overall, our results reveal the gene set responding to and involved in PST accumulation in scallop gills, which will deepen our understanding of the molecular mechanism of bivalve resistance to PST

Achieving Highly Efficient, Selective, and Stable CO2 Reduction on Nitrogen-Doped Carbon Nanotubes

The challenge in the electrosynthesis of fuels from CO2 is to achieve durable and active performance with cost-effective catalysts. Here, we report that carbon nanotubes (CNTs), doped with nitrogen to form resident electron-rich defects, can act as highly efficient and, more importantly, stable catalysts for the conversion of CO2 to CO. The unprecedented overpotential (-0.18 V) and selectivity (80%) observed on nitrogen-doped CNTs (NCNTs) are attributed to their unique features to facilitate the reaction, including (i) high electrical conductivity, (ii) preferable catalytic sites (pyridinic N defects), and (iii) low free energy for CO2 activation and high barrier for hydrogen evolution. Indeed, DFT calculations show a low free energy barrier for the potential-limiting step to form key intermediate COOH as well as strong binding energy of adsorbed CON and weak binding energy for the adsorbed CO. The highest selective site toward CO production is pyridinic N, and the NCNT-based electrodes exhibit no degradation over 10 h of continuous operation, suggesting the structural stability of the electrode