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1. Quantifying Soil Phosphorus Dynamics: A Data Assimilation Approach

   https://doi.org/10.1029/2018JG004903  

   Hou, Enqing; Lu, Xingjie; Jiang, Lifen; Wen, Dazhi; Luo, Yiqi (July 2019, Journal of Geophysical Research: Biogeosciences)

   Abstract The dynamics of soil phosphorus (P) control its bioavailability. Yet it remains a challenge to quantify soil P dynamics. Here we developed a soil P dynamics (SPD) model. We then assimilated eight data sets of 426‐day changes in Hedley P fractions into the SPD model, to quantify the dynamics of six major P pools in eight soil samples that are representative of a wide type of soils. The performance of our SPD model was better for labile P, secondary mineral P, and occluded P than for nonoccluded organic P (Po) and primary mineral P. All parameters describing soil P dynamics were approximately constrained by the data sets. The average turnover rates were labile P 0.040 g g⁻¹day⁻¹, nonoccluded Po 0.051 g g⁻¹day⁻¹, secondary mineral P 0.023 g g⁻¹day⁻¹, primary mineral P 0.00088 g g⁻¹day⁻¹, occluded Po 0.0066 g g⁻¹day⁻¹, and occluded inorganic P 0.0065 g g⁻¹day⁻¹, in the greenhouse environment studied. Labile P was transferred on average more to nonoccluded Po (transfer coefficient of 0.42) and secondary mineral P (0.38) than to plants (0.20). Soil pH and organic C concentration were the key soil properties regulating the competition for P between plants and soil secondary minerals. The turnover rate of labile P was positively correlated with that of nonoccluded Po and secondary mineral P. The pool size of labile P was most sensitive to its turnover rate. Overall, we suggest data assimilation can contribute significantly to an improved understanding of soil P dynamics. 

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2. A High‐Performance Symmetric Supercapacitor from Porous Activated Carbon under Compression

   https://doi.org/10.1002/ente.202100068  

   Sun, Wei; Zhang, Yulin; Yang, Fuqian (April 2021, Energy Technology)

   The realization of biomass‐derived supercapacitors of high performance is of practical importance for the manufacturing of supercapacitors from green and renewable sources. Herein, the feasibility of constructing high‐performance supercapacitors from potato‐derived activated carbon (AC) is demonstrated. The potato‐derived AC is produced from potato mash through hydrothermal treatment and high‐temperature activation with KOH as agent. The supercapacitors with aqueous electrolyte of 6 mKOH and a mass loading of 5 mg per electrode achieve a specific gravimetric capacitance of 333.7 F g⁻¹per electrode and a specific energy of 11.75 W h g⁻¹at a specific power of 197.6 W kg⁻¹at a current density of 0.4 A g⁻¹under a nominal compressive stress of 7.96 MPa. The supercapacitors with a mass loading of 10 mg per electrode achieve the maximum specific gravimetric capacitance of 340.6 F g⁻¹and a specific energy of 11.75 W h g⁻¹at a specific power of 194.2 W kg⁻¹at a current density of 0.4 A g⁻¹under a nominal compressive stress of 7.96 MPa. Increasing the compaction of electrode materials under compressive stress has the potential to increase the electrochemical performance of supercapacitors. 

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3. Molybdenum Carbide Electrocatalyst In Situ Embedded in Porous Nitrogen‐Rich Carbon Nanotubes Promotes Rapid Kinetics in Sodium‐Metal–Sulfur Batteries

   https://doi.org/10.1002/adma.202106572  

   Hao, Hongchang; Wang, Yixian; Katyal, Naman; Yang, Guang; Dong, Hui; Liu, Pengcheng; Hwang, Sooyeon; Mantha, Jagannath; Henkelman, Graeme; Xu, Yixin; et al (May 2022, Advanced Materials)

   Abstract This is the first report of molybdenum carbide‐based electrocatalyst for sulfur‐based sodium‐metal batteries. MoC/Mo₂C is in situ grown on nitrogen‐doped carbon nanotubes in parallel with formation of extensive nanoporosity. Sulfur impregnation (50 wt% S) results in unique triphasic architecture termed molybdenum carbide–porous carbon nanotubes host (MoC/Mo₂C@PCNT–S). Quasi‐solid‐state phase transformation to Na₂S is promoted in carbonate electrolyte, with in situ time‐resolved Raman, X‐ray photoelectron spectroscopy, and optical analyses demonstrating minimal soluble polysulfides. MoC/Mo₂C@PCNT–S cathodes deliver among the most promising rate performance characteristics in the literature, achieving 987 mAh g⁻¹at 1 A g⁻¹, 818 mAh g⁻¹at 3 A g⁻¹, and 621 mAh g⁻¹at 5 A g⁻¹. The cells deliver superior cycling stability, retaining 650 mAh g⁻¹after 1000 cycles at 1.5 A g⁻¹, corresponding to 0.028% capacity decay per cycle. High mass loading cathodes (64 wt% S, 12.7 mg cm⁻²) also show cycling stability. Density functional theory demonstrates that formation energy of Na₂S_x(1 ≤x ≤ 4) on surface of MoC/Mo₂C is significantly lowered compared to analogous redox in liquid. Strong binding of Na₂S_x(1 ≤x ≤ 4) on MoC/Mo₂C surfaces results from charge transfer between the sulfur and Mo sites on carbides’ surface. 

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4. Cobalt doping of tin disulfide/reduced graphene oxide nanocomposites for enhanced pseudocapacitive sodium-ion storage

   https://doi.org/10.1038/s42004-018-0086-z  

   Jia, Hao; Chen, Chen; Oladele, Olabode; Tang, Yongan; Li, Guoqing; Zhang, Xiangwu; Yan, Fei (November 2018, Communications Chemistry)

   Abstract Rechargeable sodium-ion batteries are receiving intense interest as a promising alternative to lithium-ion batteries, however, the absence of high-performance anode materials limits their further commercialization. Here we prepare cobalt-doped tin disulfide/reduced graphene oxide nanocomposites via a microwave-assisted hydrothermal approach. These nanocomposites maintain a capacity of 636.2 mAh g⁻¹after 120 cycles under a current density of 50 mA g⁻¹, and display a capacity of 328.3 mA h g⁻¹after 1500 cycles under a current density of 2 A g⁻¹. The quantitative capacitive analysis demonstrates that the electrochemical performance of the nanocomposite originates from the combined effects of cobalt and sulfur doping, resulting in the enhanced pseudocapacitive contribution (52.8 to 89.8% at 1 mV s⁻¹) of tin disulfide. This work provides insight into tuning the structure of layered transition metal dichalcogenides via heteroatom doping to develop high-performance anode materials for sodium-ion batteries. 

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5. Hydrological seasonality is a major driver of ecosystem metabolism in tropical nonwadeable rivers

   https://doi.org/10.1002/lno.70132  

   Castillo, María M; Ulseth, Amber J; Jarquín‐Sánchez, Aarón; Álvarez‐Merino, Arturo; Capps, Krista A (July 2025, Limnology and Oceanography)

   Abstract Studies of annual patterns of ecosystem metabolism in rivers have primarily been conducted in temperate ecosystems, and little is known about metabolic regimes of tropical rivers. We estimated ecosystem metabolism in four nonwadeable rivers in southern México that varied in size and the extent of human disturbance. The smaller rivers with limited human disturbance showed reduced gross primary production (GPP; 1.0 and 1.7 g O₂m⁻² d⁻¹), ecosystem respiration (ER; − 1.9 g O₂m⁻²d⁻¹), and net ecosystem production (NEP) approaching autotrophy (− 0. 8 and − 0.3 g O₂m⁻²d⁻¹) relative to rivers draining larger, more disturbed catchments (GPP, 1.2 and 2.7 g O₂m⁻²d⁻¹; ER, − 5.7 and − 6.9 g O₂m⁻²d⁻¹; NEP, − 3.8 and − 3.7 g O₂m⁻²d⁻¹). In all rivers, GPP and ER varied seasonally with discharge. The smaller rivers exhibited a distinct pattern of greater and sustained GPP during periods of low discharge, a seasonal metabolic regime we describe as “flow decline.” In general, process–discharge relationships exhibited thresholds, with an initial decline in GPP and ER, with increasing discharge and an increase in ER at higher flows. Relative to larger and more disturbed watersheds, smaller rivers showed a more constrained metabolic fingerprint. Annual NEP (− 1033 and − 641 g C m⁻² yr⁻¹) in the larger rivers was more negative than the global average, supporting evidence from other studies that tropical rivers are greater contributors to CO²emissions than temperate ecosystems. Our study indicates that hydrological seasonality is a major driver of metabolism in tropical rivers. 

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