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[Display omitted] • GDLs with patterned hydrophobicity have been investigated for PEFCs. • Three different wettability patterns have been proposed. • Their effect on the fuel cell performance was compared to the uniformly treated GDLs. • GDLs with patterned hydrophobicity showed superior fuel cell performance. • The patterned GDLs demonstrated less oxygen transport resistance. Flooding of the cathode due to water accumulation is one of the biggest limiting factors in the performance of polymer electrolyte fuel cells (PEFCs). This study therefore attempts to solve this issue by fabricating gas diffusion layers (GDLs) with differently patterned hydrophobic regions. The GDLs in three different patterns (triangular, diamond, and inverted-triangular) were prepared by brushing a Polytetrafluoroethylene (PTFE) solution onto commercial carbon papers through a mask and tested in PEFCs. The patterned GDLs results in superior performance in all cases compared to a uniformly PTFE-treated GDL. Notably, the oxygen transport resistance is significantly reduced, indicating that the water accumulation in the cathode is avoided. This is attributed to the patterned hydrophobicity gradient providing distinct pathways for water and oxygen. The GDL with triangular patterning displays the highest peak power density, due to the fact that the untreated less hydrophobic region is in direct contact with the cathode outlet in this case, facilitating the removal of excess liquid water. Overall, the study confirms that the GDLs with patterned hydrophobicity could be used to enhance the performance of commercial PEFC systems by facilitating water management, potentially leading to improved efficiency and durability. [ABSTRACT FROM AUTHOR]

In this paper, we conduct an empirical evaluation of currency hedging (FXH) strategies designed for Latin American investors managing portfolios of US assets with performance measured in their local currency. By analyzing the volatility and value-at-risk (VaR) of the hedged portfolio, our results reveal that FXH is inefficient in lowering portfolio risk when applied to underlying foreign risk-assets like equities and low credit quality corporate bonds. Conversely, a significant reduction in volatility is evident with FXH when the investments are in safer assets, such as high-grade government and corporate bonds. • We focused on Latin American investors that invest in assets denominated in USD. • We studied effectiveness of FX hedging strategies on reducing portfolio risk. • There are no optimal strategies when the portfolio is composed by risky assets. • Hedging currency risk is recommended for high-quality assets. [ABSTRACT FROM AUTHOR]

The role of green financing in propelling corporate green transformation and sustainable growth has attracted a lot of interest. Regarding their function in promoting corporate green transformation, green bonds—a crucial part of green finance—pose an important research question. This study, targeting Chinese A-share listed corporates, employing double machine learning models, aims to delve into the impact and mechanisms of green bond issuance on corporate green transformation. The findings indicate that issuing green bonds significantly drives corporate green transformation, especially in state-owned, smaller-scale, and non-manufacturing firms, where the impact is more evident. Further analysis discloses that green bond issuance primarily facilitates corporate green transformation through its functions in green investment and financing, green regulatory compliance, and green governance. This study serves as a theoretical reference, guiding businesses in seizing emerging opportunities in the green bond market and actively undertaking green transformation projects, thereby catalyzing a comprehensive economic transition. [ABSTRACT FROM AUTHOR]

Among the different metal nanoparticles for formulating inkjet-based conductive inks, gold remains the best choice for fabricating different patterns on economical and bio-degradable substrates such as commercial photo papers for developing low-cost sensing devices. Formulating customized gold nanoparticle (AuNPs) inks remains challenging as the ink must meet specific physical, chemical and rheological properties to achieve appropriate jettable behaviour and printable characteristics. It should exhibit well-controlled viscoelastic response for the smooth and optimized flow through the nozzles and then cure immediately to facilitate the shape retention of deposited feature. In this work, the jettability window definition framework using dimensionless numbers such as Re, We, Ca, and Z are defined for the aqueous-based AuNPs inks synthesized via ultrasonic spray pyrolysis technique and formulated into three concentration levels of 300, 600, and 1200 ppm. A theoretical CFD based simulation study is conducted to observe the ink droplet formation behaviour at different droplet velocities through inkjet nozzle. Among these formulated inks, 1200 ppm shows the most favourable behaviour as obtained through the simulation and jettability window results. It is tested further to see how different printing settings, like pulse voltage and number of repetitions, affected the continuity and density of the ink, affecting the quality of the printed AuNPs. This work demonstrates the process capabilities of inkjet printing technology by testing the formulated AuNPs ink. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile and scalable self-assembly of perylene diimide polymer with carbon paper. • Effective facilitation of carrier separation by π-π built-in electric field. • Narrowed band gap and low VB due to the VB tail states induced by π-π interactions. • Enhanced photocatalytic water oxidation activity of the PDIP/CP photocatalyst sheet. • Suitability of the PDIP/CP photocatalyst sheet for large-scale applications. Photocatalytic water splitting is a highly promising future energy technology. In contrast to the extensive work on particulate photocatalysts, there is still a lack of sufficient investigation for regularized photocatalysts. Here, from perylene diimide polymer (PDIP) and commercial carbon paper (CP), we develop a self-assembled PDIP/CP photocatalyst sheet that is easily scalable and can be used for photocatalytic water oxidation. Driven by strong interfacial π-π interactions, the PDIP spontaneously adsorbs onto the CP, which leads to a narrowed band gap, down-shifted VB edge, and enhanced separation of the photogenerated charge carriers of the PDIP. Under visible light, the PDIP/CP photocatalyst sheet shows significantly enhanced photocatalytic water oxidation activity (4 h cumulative oxygen evolution is 1.7 times higher than that of the powder-suspended system) and considerable cycling stability. The PDIP/CP photocatalyst sheet has the potential for large-scale device applications. [ABSTRACT FROM AUTHOR]