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The electronic structure of active metal centers plays an indispensable role in regulating catalytic reactivity in heterogeneous catalysis, developing other metals as promoters to decorate electronic state is a common strategy, while non‐metal component of carbon as electronic additives to regulate d‐band center has rarely been studied in thermal‐catalysis field. Herein, we report electron‐deficient tetrahedral Co(II) (Td‐cobalt(II)) centers through carbon‐layer modulation for propane dehydrogenation (PDH). It is indicated that bifunctional sites of both Td‐cobalt(II) and metallic‐cobalt are designed, and the in situ generated carbon through the disproportionation of CO on metallic‐cobalt can cover the inactive metallic‐cobalt and tailor d‐band of active Td‐cobalt(II) simultaneously. More importantly, the pre‐deposited carbon‐layer is proposed to decrease electron density of Td‐cobalt(II) and make d‐band center closer to Fermi level, consequently promotes C−H activation in PDH reaction. This study provides new perspective for the utilization of inactive carbon as electronic promoters and unlocks new opportunity to fabricate efficient PDH and other heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

Microbial communities that reduce nitrous oxide (N2O) are divided into two clades, nosZI and nosZII. These clades significantly differ in their ecological niches and their implications for N2O emissions in terrestrial environments. However, our understanding of N2O reducers in aquatic systems is currently limited. This study investigated the relative abundance and diversity of nosZI‐ and nosZII‐type N2O reducers in rivers and their impact on N2O emissions. Our findings revealed that stream sediments possess a high capacity for N2O reduction, surpassing N2O production under high N2O/NO3‐ ratio conditions. This study, along with others in freshwater systems, demonstrated that nosZI marginally dominates more often in rivers. While microbes containing either nosZI and nosZII were crucial in reducing N2O emissions, the net contribution of nosZII‐containing microbes was more significant. This can be attributed to the nir gene co‐occurring more frequently with the nosZI gene than with the nosZII gene. The diversity within each clade also played a role, with nosZII species being more likely to function as N2O sinks in streams with higher N2O concentrations. Overall, our findings provide a foundation for a better understanding of the biogeography of stream N2O reducers and their effects on N2O emissions. [ABSTRACT FROM AUTHOR]

Pyrolysis into biochar as a soil amendment has been treated as an eco‐friendly and environmentally sustainable method to recycle biogas residue (BR). However, the effect of BR biochar on soil bacterial community, mineralization, and structure of organic carbon (OC) remains unrevealed, which limits the soil application of BR biochar. This study performed a microcosm incubation experiment for a sandy soil with BR and BR‐derived biochar produced at relatively low (300°C) and high (600°C) temperature (BC300 and BC600), and explored the shift in bacterial community, mineralization, and structure of OC. Results showed that BR decreased the richness and diversity of bacterial community by 19.0%–28.0%, while BR biochar caused lower reduction (4.0%–7.0%), suggesting the potential of pyrolysis in mitigating the harmful effect of BR in bacterial community. Fourier‐transform ion cyclotron resonance mass spectrometry and 13C nuclear magnetic resonance demonstrated that BR and BR biochar shifted dissolved OC toward components with 12.0%–26.0% higher molecular weight and 18.0%–21.0% more aromatics but 10.0%–22.0% lower polarity and less protein‐, carbohydrate‐, and tannin‐like species, with the shift extent being stronger for BC600. Furthermore, BC600 increased the aromaticity of bulk OC but reduced the carbohydrate, possibly due to more Actinobacteria genera. Additionally, BR significantly elevated the amount and rate of soil carbon mineralization, while the potentially mineralizable C was the lowest in the BC600‐treated soil. These findings suggested that the pyrolysis into biochar at high temperature would be a promising way to treat BR in terms of soil bacterial community richness/diversity and carbon sequestration. [ABSTRACT FROM AUTHOR]