Hydrogen Spillover Accelerates Electrocatalytic Semi-hydrogenation of Acetylene in Membrane Electrode Assembly Reactor.

Electrocatalytic acetylene semi-hydrogenation (EASH) offers a promising and environmentally friendly pathway for the production of C2H4, a widely used petrochemical feedstock. While the economic feasibility of this route has been demonstrated in three-electrode systems, its viability in practical device remains unverified. In this study, we designed a highly efficient electrocatalyst based on a PdCu alloy system utilizing the hydrogen spillover mechanism. The catalyst achieved an operational current density of 600 mA cm-2 in a zero-gap membrane electrode assembly (MEA) reactor, with the C2H4 selectivity exceeding 85%. This data confirms the economic feasibility of EASH in real-world applications. Furthermore, through in situ Raman spectroscopy and theoretical calculations, we elucidated the catalytic mechanism involving interfacial hydrogen spillover. Our findings underscore the economic viability and potential of EASH as a greener and scalable approach for C2H4 production, thus advancing the field of electrocatalysis in sustainable chemical synthesis.

Spatial heterogeneity and management challenges of ecosystem service trade-offs: a case study in Guangdong Province, China.

Ecosystem services (ESs) play a crucial connecting role between human well-being and natural ecosystems. Investigating ESs and their interrelationships can aid in the rational distribution of resources and benefits and inform planning decisions that align with the principles of ecological civilization. Nonetheless, our current understanding of these relationships remains limited; thus, further theoretical exploration is required. This study employs the InVEST model to assess the key ESs in Guangdong Province for 2000 and 2018 and applies the multi-scale geographically weighted regression (MGWR) method to identify the primary drivers of ES changes and capture trends in spatial variations. The results showed that (1) from 2000 to 2018, the total carbon storage (CS) and habitat quality (HQ) decreased while the water yield (WY) and net primary productivity (NPP) increased. These ESs also showed spatial differences, with higher values observed in the hilly and mountainous areas of the north compared with the coastal and plain areas of the south. (2) Although the spatial distribution of ES trade-off strength varied, the overall pattern remained consistent from 2000 to 2018. The pairwise trade-off strength of CS-WY and WY-HQ decreased significantly in the northern region of Guangdong due to low rainfall, while that of CS-HQ decreased significantly in the Pearl River delta as a result of urbanization. Cultivated and forested land displayed higher and lower levels of NPP and WY, respectively, with forested land exhibiting greater trade-off strength than the other land use types. (3) Evident spatial heterogeneity was observed in the properties and intensity of the correlations between driving factors and changes in ES trade-offs. Natural factors were the primary determinants of trade-offs among ESs. However, at a regional scale, the landscape index and socioeconomic factors tended to represent stronger drivers. Based on these findings, we suggest that ecological management should be adjusted based on the geographic scale. This study offers a valuable approach to understanding the relationship between ES trade-offs and their drivers in geographic space and serves as a reference for the sustainable provisioning of ESs both locally and globally.

New Hybrid Method for the Calculation of the Solvation Free Energy of Small Molecules in Aqueous Solutions.

The ability to accurately predict the solvation free energies of ionic species using the appropriate thermodynamic cycle is of great importance in many areas of chemistry and biochemistry. To improve the accuracy of calculating solvation free energies, we devised a hybrid cluster-continuum approach, where explicit solvent molecules are added to the traditionally employed continuum model. Our computational workflow consists of the following steps: First, the minimum number of explicit water molecules beyond which additional water molecules no longer improve the accuracy of the cluster-continuum model is carefully established. Next, the convergence values for fully relaxed molecular configurations are compared with those obtained by sampling thermally disordered configurations using single-point calculations. We find that the dielectric constant does not have a significant influence on the solvation free energy, while accounting for the placement of a counterion is necessary for the accurate calculation of the solvation free energy.