Southwest University of Science and Technology

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.

Adhesive hydrogels are attractive biomaterials for various applications, such as electronic skin, wound dressing, and wearable devices. However, fabricating a hydrogel with both adequate adhesiveness and excellent mechanical properties remains a challenge. Inspired by the adhesion mechanism of mussels, we used a two-step process to develop an adhesive and tough polydopamine-clay-polyacrylamide (PDA-clay-PAM) hydrogel. Dopamine was intercalated into clay nanosheets and limitedly oxidized between the layers, resulting in PDA-intercalated clay nanosheets containing free catechol groups. Acrylamide monomers were then added and in situ polymerized to form the hydrogel. Unlike previous single-use adhesive hydrogels, our hydrogel showed repeatable and durable adhesiveness. It adhered directly on human skin without causing an inflammatory response and was easily removed without causing damage. The adhesiveness of this hydrogel was attributed to the presence of enough free catechol groups in the hydrogel, which were created by controlling the oxidation process of the PDA in the confined nanolayers of clay. This mimicked the adhesion mechanism of the mussels, which maintain a high concentration of catechol groups in the confined nanospace of their byssal plaque. The hydrogel also displayed superior toughness, which resulted from nanoreinforcement by clay and PDA-induced cooperative interactions with the hydrogel networks. Moreover, the hydrogel favored cell attachment and proliferation, owning to the high cell affinity of PDA. Rat full-thickness skin defect experiments demonstrated that the hydrogel was an excellent dressing. This free-standing, adhesive, tough, and biocompatible hydrogel may be more convenient for surgical applications than adhesives that involve in situ gelation and extra agents.

The g-C 3 N 4 with dual defect sites exhibits excellent photocatalytic H 2 O 2 generation activity and selectivity, and the key role of each defect site in the surface reaction mechanism is revealed.

Abstract The discovery of stable and noble‐metal‐free catalysts toward efficient electrochemical reduction of nitrogen (N 2 ) to ammonia (NH 3 ) is highly desired and significantly critical for the earth nitrogen cycle. Here, based on the theoretical predictions, MoS 2 is first utilized to catalyze the N 2 reduction reaction (NRR) under room temperature and atmospheric pressure. Electrochemical tests reveal that such catalyst achieves a high Faradaic efficiency (1.17%) and NH 3 yield (8.08 × 10 −11 mol s −1 cm −1 ) at −0.5 V versus reversible hydrogen electrode in 0.1 m Na 2 SO 4 . Even in acidic conditions, where strong hydrogen evolution reaction occurs, MoS 2 is still active for the NRR. This work represents an important addition to the growing family of transition‐metal‐based catalysts with advanced performance in NRR.

High-entropy alloys (HEAs), which are defined as near-equimolar alloys of five or more elements, are attracting ever increasing attention because of the unique properties in a variety of applications. Recently, HEAs have already exhibited remarkable catalytic performance toward several thermal-driven and electrocatalytic reactions. HEAs not only regulate the electronic and geometric structures to a large degree but also serve as a platform to construct catalysts with unexpected performance. Herein, recent advances regarding HEA-based catalysis are systematically summarized, with a special focus on the synthetic methods for HEA-based catalysts, catalytic performance, and mechanistic understanding. Moreover, the challenges and future opportunities for this research area are carefully discussed. A series of open questions and promising directions to be explored are proposed, including synthetic methods, regulation of electronic properties, identification of active centers, and applications into photocatalysis. This Review provides an overview about the progress, challenges, and opportunities for HEA-based catalysis.

Abstract Achieving active and stable oxygen evolution reaction (OER) in acid media based on single-atom catalysts is highly promising for cost-effective and sustainable energy supply in proton electrolyte membrane electrolyzers. Here, we report an atomically dispersed Ru 1 -N 4 site anchored on nitrogen-carbon support (Ru-N-C) as an efficient and durable electrocatalyst for acidic OER. The single-atom Ru-N-C catalyst delivers an exceptionally intrinsic activity, reaching a mass activity as high as 3571 A g metal −1 and turnover frequency of 3348 O 2 h −1 with a low overpotential of 267 mV at a current density of 10 mA cm −2 . The catalyst shows no evident deactivation or decomposition after 30-hour operation in acidic environment. Operando synchrotron radiation X-ray absorption spectroscopy and infrared spectroscopy identify the dynamic adsorption of single oxygen atom on Ru site under working potentials, and theoretical calculations demonstrate that the O-Ru 1 -N 4 site is responsible for the high OER activity and stability.

As a non‐toxic species, Zn fulfills a multitude of biological roles, but its promoting effect on electrocatalysis has been rarely explored. Herein, the theoretic predications and experimental investigations that nonelectroactive Zn behaves as an effective promoter for CoP‐catalyzed hydrogen evolution reaction (HER) in both acidic and alkaline media is reported. Density function theory calculations reveal that Zn doing leads to more thermal‐neutral hydrogen adsorption free energy and thus enhanced HER activity for CoP catalyst. Electrochemical tests show that a Zn 0.08 Co 0.92 P nanowall array on titanium mesh (Zn 0.08 Co 0.92 P/TM) needs overpotentials of only 39 and 67 mV to drive a geometrical catalytic current of 10 mA cm ‐2 in 0.5 m H 2 SO 4 and 1.0 m KOH, respectively. This Zn 0.08 Co 0.92 P/TM is also superior in activity over CoP/TM for urea oxidation reaction (UOR), driving 115 mA cm ‐2 at 0.6 V in 1.0 m KOH with 0.5 m urea. The high HER and UOR activity of this bifunctional electrode enables a Zn 0.08 Co 0.92 P/TM‐based two‐electrode electrolyzer for energy‐saving hydrogen production, offering 10 mA cm ‐2 at a low voltage of 1.38 V with strong long‐term electrochemical stability.

Owing to the four features summarized in this review, <italic>i.e.</italic>, low-cost resource, high-power performance, all-climate adaptability and full-batty recyclability, sodium ion batteries show great promise for large-scale energy storage systems used for the application of renewable energy sources and smart grids.

An ideal hydrogel for biomedical engineering should mimic the intrinsic properties of natural tissue, especially high toughness and self-healing ability, in order to withstand cyclic loading and repair skin and muscle damage. In addition, excellent cell affinity and tissue adhesiveness enable integration with the surrounding tissue after implantation. Inspired by the natural mussel adhesive mechanism, we designed a polydopamine–polyacrylamide (PDA–PAM) single network hydrogel by preventing the overoxidation of dopamine to maintain enough free catechol groups in the hydrogel. Therefore, the hydrogel possesses super stretchability, high toughness, stimuli-free self-healing ability, cell affinity and tissue adhesiveness. More remarkably, the current hydrogel can repeatedly be adhered on/stripped from a variety of surfaces for many cycles without loss of adhesion strength. Furthermore, the hydrogel can serve as an excellent platform to host various nano-building blocks, in which multiple functionalities are integrated to achieve versatile potential applications, such as magnetic and electrical therapies. A self-healing, super-resilient hydrogel that can accelerate skin regeneration has been made using an adhesive mechanism inspired by mussels. Hydrogels have similar structures to soft biological tissues and have great potential for tissue engineering applications. However, most are too fragile for use in the body and lack the ability to self-heal and adhere to tissue. Now, Xiong Lu from China's Southwest Jiaotong University and co-workers have synthesized a self-healing, super-resilient hydrogel using a process that preserves PDA's catechols – substances that impart mussels with high adhesiveness – when embedded in an elastic polymer matrix. The numerous non-covalent bonds between PDA catechols enable the hydrogel to perfectly re-form after being sliced open and help it stretch over 30 times its initial length without breaking. The material could also carry magnetic or conductive nanoparticles for future integrated healthcare applications. Inspired by mussel chemistry, a novel polydopamine–polyacrymide hydrogel simultaneously possesses super stretchability, stimuli-free self-healing properties, cell affinity and tissue adhesiveness. The current hydrogel lasts its adhesiveness for a long term, and can be repeatedly adhered on/stripped from a variety of substrates. The hydrogel can host various nano-building blocks and be tuned to magnetic and conductive hydrogels with above-mentioned properties.

Rechargeable lithium-ion (Li-ion) and lithium-polymer (Li-poly) batteries have recently become dominant in consumer electronic products because of advantages associated with energy density and product longevity. However, the small size of these batteries, the high rate of disposal of consumer products in which they are used, and the lack of uniform regulatory policy on their disposal means that lithium batteries may contribute substantially to environmental pollution and adverse human health impacts due to potentially toxic materials. In this research, we used standardized leaching tests, life-cycle impact assessment (LCIA), and hazard assessment models to evaluate hazardous waste classification, resource depletion potential, and toxicity potentials of lithium batteries used in cellphones. Our results demonstrate that according to U.S. federal regulations, defunct Li-ion batteries are classified hazardous due to their lead (Pb) content (average 6.29 mg/L; σ = 11.1; limit 5). However, according to California regulations, all lithium batteries tested are classified hazardous due to excessive levels of cobalt (average 163,544 mg/kg; σ = 62,897; limit 8000), copper (average 98,694 mg/kg; σ = 28,734; limit 2500), and nickel (average 9525 mg/kg; σ = 11,438; limit 2000). In some of the Li-ion batteries, the leached concentrations of chromium, lead, and thallium exceeded the California regulation limits. The environmental impact associated with resource depletion and human toxicity is mainly associated with cobalt, copper, nickel, thallium, and silver, whereas the ecotoxicity potential is primarily associated with cobalt, copper, nickel, thallium, and silver. However, the relative contribution of aluminum and lithium to human toxicity and ecotoxicity could not be estimated due to insufficient toxicity data in the models. These findings support the need for stronger government policy at the local, national, and international levels to encourage recovery, recycling, and reuse of lithium battery materials.

Abstract The industrial artificial fixation of atmospheric N 2 to NH 3 is carried out using the Haber–Bosch process that is not only energy‐intensive but emits large amounts of greenhouse gas. Electrochemical reduction offers an environmentally benign and sustainable alternative for NH 3 synthesis. Although Mo‐dependent nitrogenases and molecular complexes effectively catalyze the N 2 fixation at ambient conditions, the development of a Mo‐based nanocatalyst for highly performance electrochemical N 2 fixation still remains a key challenge. Here, greatly boosted electrocatalytic N 2 reduction to NH 3 with excellent selectivity by defect‐rich MoS 2 nanoflowers is reported. In 0.1 m Na 2 SO 4 , this catalyst attains a high Faradic efficiency of 8.34% and a high NH 3 yield of 29.28 µg h −1 mg −1 cat. at − 0.40 V versus reversible hydrogen electrode, much larger than those of defect‐free counterpart (2.18% and 13.41 µg h −1 mg −1 cat. ), with strong electrochemical stability. Density functional theory calculations show that the potential determining step has a lower energy barrier (0.60 eV) for defect‐rich catalyst than that of defect‐free one (0.68 eV).

Significance Atmospheric ammonia plays important roles in fine particle pollution, acid rain, and nitrogen deposition. China, known as the world’s top emitter of gaseous ammonia, plans to control ammonia emissions to mitigate the haze pollution that has recently emerged. However, the complex side effects are still unclear. By integrating a chemical transport model, nationwide measurements, and a sophisticated ammonia emission model, we find that ammonia emission control would significantly aggravate acid rain pollution, thereby offsetting the benefit from reduced fine particle pollution and nitrogen deposition. Our work suggests that region-specific ammonia-control strategies provide a more rational and effective way to achieve the dual benefits of protecting human and ecosystem health in China.

Abstract A graphitic carbon nitride/rGO/perylene diimide polymer (g‐C 3 N 4 /rGO/PDIP) Z‐scheme heterojunction is successfully constructed to realize high‐flux charge transfer and efficient photocatalytic overall water splitting. A giant internal electric field in the Z‐scheme junction is built, enabling the charge separation efficiency to be enhanced dramatically by 8.5 times. Thus, g‐C 3 N 4 /rGO/PDIP presents an efficient and stable photocatalytic overall water splitting activity with H 2 and O 2 evolution rate of 15.80 and 7.80 µmol h −1 , respectively, ≈12.1 times higher than g‐C 3 N 4 nanosheets. Meanwhile, a notable quantum efficiency of 4.94% at 420 nm and solar‐to‐hydrogen energy‐conversion efficiency of 0.30% are achieved, prominently surpassing many reported g‐C 3 N 4 ‐based photocatalysts. Briefly, this work throws light on enhancing the internal electric field by interface control to dramatically improve the photocatalytic performance.

Radio frequency identification system (RFID) is an automatic technology and aids machines or computers to identify objects, record metadata or control individual target through radio waves. Connecting RFID reader to the terminal of Internet, the readers can identify, track and monitor the objects attached with tags globally, automatically, and in real time, if needed. This is the so-called Internet of Things (IoT). RFID is often seen as a prerequisite for the IoT. This paper introduces the technologies of RFID and IoT, discusses the applications and challenges of RFID technology used in IoT.

Heteratom doping is a possible way to tune the hydrogen evolution reaction (HER) catalytic capability of electrocatalysts. In this work, we report the development of Mn-doped CoP (Mn–Co–P) nanosheets array on Ti mesh (Mn–Co–P/Ti) as an efficient 3D HER electrocatalyst with good stability at all pH values. Electrochemical tests demonstrate that Mn doping leads to enhanced catalytic activity of CoP. In 0.5 M H2SO4, this Mn–Co–P/Ti catalyst drives 10 mA cm–2 at an overpotential of 49 mV, which is 32 mV less than that for CoP/Ti. To achieve the same current density, it demands overpotentials of 76 and 86 mV in 1.0 M KOH and phosphate-buffered saline, respectively. The enhanced HER activity for Mn–Co–P can be attributed to its more thermo-neutral hydrogen adsorption free energy than CoP, which is supported by density functional theory calculations.

See Letter to the Editor on this article by Adam et al ., 26, 3756–3758 . See also Response to the Letter by Bradstock et al ., 26, e8–e9 .

Abstract The lithium–sulfur (Li–S) battery is regarded as a next‐generation energy storage system due to its conspicuous merits in high theoretical capacity (1672 mAh g −1 ), overwhelming energy density (2600 Wh kg −1 ), and the cost‐effectiveness of sulfur. However, the practical application of Li–S batteries is still handicapped by a multitude of key challenges, mainly pertaining to fatal lithium polysulfide (LiPS) shuttling and sluggish sulfur redox kinetics. In this respect, rationalizing electrocatalytic processes in Li–S chemistry to synergize the entrapment and conversion of LiPSs is of paramount significance. This review summarizes recent progress and well‐developed strategies of the mediator design toward promoted Li–S chemistry. The current advances, existing challenges, and future directions are accordingly highlighted, aiming at providing in‐depth understanding of the sulfur reaction mechanism and guiding the rational mediator design to realize high‐energy and long‐life Li–S batteries.

Abstract High‐capacity electrode materials play a vital role for high‐energy‐density lithium‐ion batteries. Silicon (Si) has been regarded as a promising anode material because of its outstanding theoretical capacity, but it suffers from an inherent volume expansion problem. Binders have demonstrated improvements in the electrochemical performance of Si anodes. Achieving ultrahigh‐areal‐capacity Si anodes with rational binder strategies remains a significant challenge. Herein, a binder‐lithiated strategy is proposed for ultrahigh‐areal‐capacity Si anodes. A hard/soft modulated trifunctional network binder (N‐P‐LiPN) is constructed by the partially lithiated hard polyacrylic acid as a framework and partially lithiated soft Nafion as a buffer via the hydrogen binding effect. N‐P‐LiPN has strong adhesion and mechanical properties to accommodate huge volume change of the Si anode. In addition, lithium‐ions are transferred via the lithiated groups of N‐P‐LiPN, which significantly enhances the ionic conductivity of the Si anode. Hence, the Si@N‐P‐LiPN electrodes achieve the highest initial Coulombic efficiency of 93.18% and a stable cycling performance for 500 cycles at 0.2 C. Specially, Si@N‐P‐LiPN electrodes demonstrate an ultrahigh‐areal‐capacity of 49.59 mAh cm −2 . This work offers a new approach for inspiring the battery community to explore novel binders for next‐generation high‐energy‐density storage devices.

OBJECTIVE: Spectral power analysis plays a predominant role in electroencephalogram-based emotional recognition. It can reflect activity differences among multiple brain regions. In addition to activation difference, different emotions also involve different large-scale network during related information processing. In this paper, both information propagation patterns and activation difference in the brain were fused to improve the performance of emotional recognition. METHODS: We constructed emotion-related brain networks with phase locking value and adopted a multiple feature fusion approach to combine the compensative activation and connection information for emotion recognition. RESULTS: Recognition results on three public emotional databases demonstrated that the combined features are superior to either single feature based on power distribution or network character. Furthermore, the conducted feature fusion analysis revealed the common characters between activation and connection patterns involved in the positive, neutral, and negative emotions for information processing. SIGNIFICANCE: The proposed feasible combination of both information propagation patterns and activation difference in the brain is meaningful for developing the effective human-computer interaction systems by adapting to human emotions in the real world applications.