Volatile organic compound removal by post plasma-catalysis over porous TiO2 with enriched oxygen vacancies in a dielectric barrier discharge reactor.

Non-thermal plasma (NTP) degradation of volatile organic compounds (VOCs) into CO2 and H2O is a promising strategy for addressing ever-growing environment pollution. However, its practical implementation is hindered by low conversion efficiency and emissions of noxious by-products. Herein, an advanced low-oxygen-pressure calcination process is developed to fine-tune the oxygen vacancy concentration of MOF-derived TiO2 nanocrystals. Vo-poor and Vo-rich TiO2 catalysts were placed in the back of an NTP reactor to convert harmful ozone molecules into ROS that decompose VOCs via heterogeneous catalytic ozonation processes. The results indicate that Vo-TiO2-5/NTP with the highest Vo concentration exhibited superior catalytic activity in the degradation of toluene compared to NTP-only and TiO2/NTP, achieving a maximum 96% elimination efficiency and 76% COx selectivity at an SIE of 540 J L-1. Mechanistic analysis reveals that the 1O2, ˙O2- and ˙OH species derived from the activation of O3 molecules on Vo sites contribute to the decomposition of toluene over the Vo-rich TiO2 surface. With the aid of advanced characterization and density functional theory calculations, the roles of oxygen vacancies in manipulating the synergistic capability of post-NTP systems were explored, and were attributed to increased O3 adsorption ability and enhanced charge transfer dynamics. This work presents novel insights into the design of high-efficiency NTP catalysts structured with active Vo sites.

Growth of single-crystal black phosphorus and its alloy films through sustained feedstock release.

Black phosphorus (BP), a fascinating semiconductor with high mobility and a tunable direct bandgap, has emerged as a candidate beyond traditional silicon-based devices for next-generation electronics and optoelectronics. The ability to grow large-scale, high-quality BP films is a prerequisite for scalable integrated applications but has thus far remained a challenge due to unmanageable nucleation events. Here we develop a sustained feedstock release strategy to achieve subcentimetre-size single-crystal BP films by facilitating the lateral growth mode under a low nucleation rate. The as-grown single-crystal BP films exhibit high crystal quality, which brings excellent field-effect electrical properties and observation of pronounced Shubnikov-de Haas oscillations, with high mobilities up to ~6,500 cm2 V-1 s-1 at low temperatures. We further extend this approach to the growth of single-crystal BP alloy films, which broaden the infrared emission regime of BP from 3.7 µm to 6.9 µm at room temperature. This work will greatly facilitate the development of high-performance electronics and optoelectronics based on BP family materials.

Unraveling the Strong Fluorescence Enhancement of HPBI Molecules by ZIF-8 Colloidal Suspensions via Adsorption Analysis.

Enhancing the fluorescence of organic dye by colloidal particles is one of the most promising routes to optimize fluorescence detection. However, in addition to metallic particles, which serve as the most frequently used particles and have been found to employ the plasmonic resonance to provide strong fluorescence enhancement, neither new types of colloidal particles nor new fluorescence mechanisms have been intensively explored in recent years. In this work, strongly enhanced fluorescence was observed when 2-(2-hydroxyphenyl)-1H-benzimidazole (HPBI) molecules were simply mixed with zeolitic imidazolate framework-8 (ZIF-8) colloidal suspensions. Moreover, the enhancement factor ΔI = IHPBI+ZIF-8/IHPBI does not increase accordingly with the increasing amount of HPBI. To find out how the strong fluorescence was triggered and affected by the amount of HPBI, multiple techniques were applied to analyze the adsorption behavior. By combining analytical ultracentrifugation with first-principles calculations, we proposed that HPBI molecules were adsorbed onto the surface of ZIF-8 particles coordinatively and electrostatically, depending on the concentration of HPBI molecules. The coordinative adsorption would result in a new kind of fluorescence emitter. The new fluorescence emitters tend to distribute on the outer surface of ZIF-8 particles periodically. The distance between each fluorescence emitter is fixed and much smaller than the wavelength of the excitation light. Thus, it can be concluded that collective spontaneous emission might be triggered.

How ex-employee citizenship behavior is generated: From the perspective of legacy identification.

The termination of employment is not the end of an organization-employee relationship. As ex-employees can provide various benefits to their former organizations, and a large number of ex-employees have accumulated in enterprises because of increased employee mobility, research on ex-employees' contribution behavior, and how it is generated are significant to organizations in making use of their ex-employees effectively and consequently improving organizational efficiency. Based on the research into organizational citizenship behavior, Study 1 extended the focus of organizational citizenship behavior research to include ex-employees, introducing the concept of ex-employee citizenship behavior. The measurement of ex-employee citizenship behavior was developed based on Hinkin's tutorial. Using social identity theory, Study 2 discussed how ex-employee citizenship behavior is generated. A two-wave survey of 291 former employees was conducted. Hierarchical regression analysis and the bootstrap method were then applied to test the hypotheses. The results showed that legacy identification was positively related to ex-employee citizenship behavior. Furthermore, the interaction between perceived organizational prestige and perceived insider status was positively related to legacy identification. Perceived organizational prestige and perceived insider status were also indirectly and interactively related to ex-employee citizenship behavior through legacy identification. The positive relationship between legacy identification and ex-employee citizenship behavior was moderated by the cooperative relationship between the current and former organizations. Additionally, the indirect positive effect of the interaction between perceived organizational prestige and perceived insider status on ex-employee citizenship behavior through legacy identification is moderated by the cooperative relationship between the current and former organizations. The theoretical and practical implications of this study were discussed. Finally, the limitations of this study were presented alongside suggestions for future research.

Ultra-stable all-solid-state sodium metal batteries enabled by perfluoropolyether-based electrolytes.

Rechargeable batteries paired with sodium metal anodes are considered to be one of the most promising high-energy and low-cost energy-storage systems. However, the use of highly reactive sodium metal and the formation of sodium dendrites during battery operation have caused safety concerns, especially when highly flammable liquid electrolytes are used. Here we design and develop solvent-free solid polymer electrolytes (SPEs) based on a perfluoropolyether-terminated polyethylene oxide (PEO)-based block copolymer for safe and stable all-solid-state sodium metal batteries. Compared with traditional PEO SPEs, our results suggest that block copolymer design allows for the formation of self-assembled nanostructures leading to high storage modulus at elevated temperatures with the PEO domains providing transport channels even at high salt concentration (ethylene oxide/sodium = 8/2). Moreover, it is demonstrated that the incorporation of perfluoropolyether segments enhances the Na+ transference number of the electrolyte to 0.46 at 80 °C and enables a stable solid electrolyte interface. The new SPE exhibits highly stable symmetric cell-cycling performance at high current density (0.5 mA cm-2 and 1.0 mAh cm-2, up to 1,000 h). Finally, the assembled all-solid-state sodium metal batteries demonstrate outstanding capacity retention, long-term charge/discharge stability (Coulombic efficiency, 99.91%; >900 cycles with Na3V2(PO4)3 cathode) and good capability with high loading NaFePO4 cathode (>1 mAh cm-2).

Novel genotypes of Coxiella burnetii circulating in rats in Yunnan Province, China.

BACKGROUND: Coxiella burnetii (Cb) is the causative agent of the zoonotic disease Q fever which is distributed worldwide. Molecular typing of Cb strains is essential to find out the infectious source and prevent Q fever outbreaks, but there has been a lack of typing data for Cb strains in China. The aim of this study was to investigate the genotypes of Cb strains in wild rats in Yunnan Province, China. RESULTS: Eighty-six wild rats (Rattus flavipectus) were collected in Yunnan Province and 8 of the 86 liver samples from the wild rats were positive in Cb-specific quantitative PCR (qPCR). The Cb strains from the 8 rats were then typed into 3 genotypes using 10-spacer multispacer sequence typing (MST), and 2 of the 3 genotypes were recognized as novel ones. Moreover, the Cb strains in the wild rats were all identified as genotype 1 using 6-loci multilocus variable number of tandem repeat analysis (MLVA). CONCLUSIONS: This is the first report of genotypic diversity of Cb strains from wild rats in China. Further studies are needed to explore the presence of more genotypes and to associate the genotypes circulating in the wildlife-livestock interaction with those causing human disease to further expand on the epidemiological aspects of the pathogen.

Breaking the Linear Relation in the Dissociation of Nitrogen on Iron Surfaces.

Current industrial ammonia synthesis depends on the Haber-Bosch process, in which the activity of the catalyst is limited by the Brønsted-Evans-Polanyi (BEP) principle and Fe is used as a commercial catalyst. Herein, we found that the dissociation barriers of N2 on Fe(111), Fe(211), Fe(110), and Fe(100) surfaces do not follow the widely accepted BEP principle. N2 dissociation on Fe(111) surface has the smallest adsorption energy and the lowest energetic barrier. Such an abnormal phenomenon can be attributed to charge transfer from Fe surfaces to the anti-bonding orbital (π*) of the absorbed N2 . More charges transferred from the Fe surface to π* of N2 leads to a weaker N≡N triple bond and a lower adsorption energy of N atoms. However, the hydrogenation of N atoms and desorption of NH3 on the four Fe surfaces follow the BEP principle. Therefore, Fe(111) is found to be the most active surface to promote ammonia synthesis, and such a conclusion is also applicable to Ni and Mo surfaces.

The Relationship Between Feedback Quality, Perceived Organizational Support, and Sense of Belongingness Among Conscientious Teleworkers.

The belongingness literature has largely examined the antecedents of non-teleworkers' sense of belongingness, but little attention has been paid to what job-related factors could affect teleworkers' sense of belongingness. Grounded in organizational support theory, our research focuses on why feedback quality from the direct leader brings sense of belongingness and considers how conscientiousness of teleworkers shapes this effect. Based on data from 329 participants obtained at three different time points from one technology service organization in China, our results indicated that teleworkers' perceived organizational support serves as an essential mediator of the positive relationship between feedback quality from the direct leader and sense of belongingness. Additionally, the teleworkers' conscientiousness strengthened the positive direct effect of feedback quality on perceived organizational support and the indirect effect on sense of belongingness. The moderating role of conscientiousness in strengthening the link between feedback quality and perceived organizational support was significant for high levels of conscientiousness and not significant for low levels. Finally, we discussed theoretical and practical implications.

Why Do I Seek Negative Feedback? Assessment Orientation, Self-Criticism, and Negative Feedback-Seeking.

Negative feedback plays an important role in employee performance improvement, yet little research has specifically examined the motivational factor that drives employees to seek negative feedback. Drawing from the regulatory mode theory, we propose that assessment orientation could increase negative feedback-seeking by triggering individual self-criticism and participative leadership could enhance this effect. Results from a two-wave lagged survey study obtained from 216 Chinese employees suggested that assessment orientation is positively correlated with negative feedback-seeking via the mediating role of self-criticism. Moreover, the positive effect of assessment orientation on self-criticism and the positive indirect effect of assessment orientation on negative feedback-seeking via self-criticism are both stronger when participative leadership is higher. These results enrich the literature on feedback-seeking and regulatory mode and are useful for increasing employee negative feedback-seeking behavior in the organization.

Defect-Engineered Graphene Films as Ozonation Catalysts for the Devastation of Sulfamethoxazole: Insights into the Active Sites and Oxidation Mechanism.

Graphene-based catalysts have been widely applied for catalytic ozonation. However, as it is difficult to obtain graphene with high structural precision, it is currently unfeasible to comprehend the relationships between the intrinsic structure of the layered carbon catalysts with its catalytic activities. Here, an advanced plasma-assisted etch strategy was used to fine tune the ozonation activity of monolayered graphene films by tailoring the defect types. Raman mapping indicated that the defects of the as-prepared monolayered graphene films were predominantly sp3, vacancy, and boundary-type defects, respectively. The roles and contributions of these active defects in manipulating the oxidative potential of monolayered graphene films were revealed by quenching experiments, electron paramagnetic resonance results, and density functional theory calculations. The catalytic results showed that the monolayered graphene films with boundary-like defects exhibited the best catalytic performance toward the degradation of sulfamethoxazole. This work contributes new insights into the design of high-efficiency carbonaceous catalysts by structuring additional defective sites.

Identification of Tick-Borne Pathogens and Genotyping of Coxiella burnetii in Rhipicephalus microplus in Yunnan Province, China.

Rhipicephalus microplus, a vector that can transmit many pathogens to humans and domestic animals, is widely distributed in Yunnan province, China. However, few reports on the prevalence of tick-borne pathogens (TBPs) in Rh. microplus in Yunnan are available. The aim of this study was to detect TBPs in Rh. microplus in Yunnan and to analyze the phylogenetic characterization of TBPs detected in these ticks. The adult Rh. microplus (n = 516) feeding on cattle were collected. The pooled DNA samples of these ticks were evaluated using metagenomic next-generation sequencing (mNGS) and then TBPs in individual ticks were identified using genus- or group-specific nested polymerase chain reaction (PCR) combined with DNA sequencing assay. As a result, Candidatus Rickettsia jingxinensis (24.61%, 127/516), Anaplasma marginale (13.18%, 68/516), Coxiella burnetii (3.10%, 16/516), and Coxiella-like endosymbiont (CLE) (8.33%, 43/516) were detected. The dual coinfection with Ca. R. jingxinensis and A. marginale and the triple coinfection with Ca. R. jingxinensis, A. marginale, and CLE were most frequent and detected in 3.68% (19/516) and 3.10% (16/516) of these ticks, respectively. The results provide insight into the diversity of TBPs and their coinfections in Rh. microplus in Yunnan province of China, reporting for the first time that C. burnetii had been found in Rh. microplus in China. Multilocus variable number tandem repeat analysis with 6 loci (MLVA-6) discriminated the C. burnetii detected in Rh. microplus in Yunnan into MLVA genotype 1, which is closely related to previously described genotypes found primarily in tick and human samples from different regions of the globe, indicating a potential public health threat posed by C. burnetii in Rh. microplus in Yunnan.

Identification of tick-borne pathogens by metagenomic next-generation sequencing in Dermacentor nuttalli and Ixodes persulcatus in Inner Mongolia, China.

BACKGROUND: Hard ticks act as arthropod vectors in the transmission of human and animal pathogens and are widely distributed in northern China. The aim of this study is to screen the important tick-borne pathogens (TBPs) carried by hard ticks in Inner Mongolia using metagenomic next-generation sequencing (mNGS) and to estimate the risk of human infection imposed by tick bites. METHODS: The adult Dermacentor nuttalli (n = 203) and Ixodes persulcatus (n = 36) ticks feeding on cattle were collected. The pooled DNA samples prepared from these ticks were sequenced as the templates for mNGS to survey the presence of TBPs at the genus level. Individual tick DNA samples were detected by genus--specific or group-specific nested polymerase chain reaction (PCR) of these TBPs and combined with DNA sequencing assay to confirm the results of mNGS. RESULTS: R. raoultii (45.32%, 92/203), Candidatus R. tarasevichiae (5.42%, 11/203), Anaplasma sp. Mongolia (26.60%, 54/203), Coxiella-like endosymbiont (CLE) (53.69%, 109/203), and Babesia venatorum (7.88%, 16/203) were detected in D. nuttalli, while R. raoultii (30.56%, 11/36), Anaplasma sp. Mongolia (27.80%, 10/36), and CLE (27.80%, 10/36) were detected in I. persulcatus. The double- and triple-pathogen/endosymbiont co-infections were detected in 40.39% of D. nuttalli and 13.89% of I. persulcatus, respectively. The dual co-infection with R. raoultii and CLE (14.29%, 29/203) and triple co-infection with R. raoultii, Anaplasma sp. Mongolia, and CLE (13.79%, 28/203) were most frequent in D. nuttalli. CONCLUSIONS: This study provides insight into the microbial diversity of D. nuttalli and I. persulcatus in Inner Mongolia, China, reporting for the first time that Candidatus R. tarasevichiae had been found in D. nuttalli in China, and for the first time in the world that Anaplasma sp. Mongolia has been detected in I. persulcatus. This study proves that various vertically transmitted pathogens co-inhabit D. nuttalli and I. persulcatus, and indicates that cattle in Inner Mongolia are exposed to several TBPs.

Catalysis based on ferroelectrics: controllable chemical reaction with boosted efficiency.

Catalysts, which can accelerate chemical reactions, show promising potential to alleviate environmental pollution and the energy crisis. However, their wide application is severely limited by their low efficiency and poor selectivity due to the recombination of photogenerated electron-hole pairs, the back-reaction of interactants. Accordingly, ferroelectrics have emerged as promising catalysts to address these issues with the advantages of promoted light adsorption, boosted catalytic efficiency as a result of their intrinsic polarization, suppressed electron-hole pair recombination, and superior selectivity via the ferroelectric switch. This review summarizes the recent research progress of catalytic studies based on ferroelectric materials and highlights the controllability of catalytic activity by the ferroelectric switch. More importantly, we also comprehensively highlight the underlying working mechanism of ferroelectric-controlled catalysis to facilitate a deep understanding of this novel chemical reaction and guide future experiments. Finally, the perspectives of catalysis based on ferroelectrics and possible research opportunities are discussed. This review is expected to inspire wide research interests and push ferroelectric catalysis to practical applications.

Towards chirality control of graphene nanoribbons embedded in hexagonal boron nitride.

The integrated in-plane growth of graphene nanoribbons (GNRs) and hexagonal boron nitride (h-BN) could provide a promising route to achieve integrated circuitry of atomic thickness. However, fabrication of edge-specific GNRs in the lattice of h-BN still remains a significant challenge. Here we developed a two-step growth method and successfully achieved sub-5-nm-wide zigzag and armchair GNRs embedded in h-BN. Further transport measurements reveal that the sub-7-nm-wide zigzag GNRs exhibit openings of the bandgap inversely proportional to their width, while narrow armchair GNRs exhibit some fluctuation in the bandgap-width relationship. An obvious conductance peak is observed in the transfer curves of 8- to 10-nm-wide zigzag GNRs, while it is absent in most armchair GNRs. Zigzag GNRs exhibit a small magnetic conductance, while armchair GNRs have much higher magnetic conductance values. This integrated lateral growth of edge-specific GNRs in h-BN provides a promising route to achieve intricate nanoscale circuits.

The Generative Mechanism of Boomerang Intention: From the Perspective of Legacy Identification.

Boomerang employment has become an increasingly significant third way to obtain employees, yet little research has focused on why does ex-employee want to come back. Drawing from social identity theory, we propose that legacy identification could increase boomerang intention and both perceived corporate prestige and psychological contract violation could affect boomerang intention through legacy identification. The cooperative relationship between the former organization and the current organization could enhance these effects. Results from a two-time points survey of 202 Chinese employees showed that legacy identification could increase boomerang intention, perceived corporate prestige could increase boomerang intention via legacy identification, psychological contract violation could decrease boomerang intention via legacy identification. Besides, the positive effect of legacy identification on boomerang intention, the positive indirect effect of corporate prestige on boomerang intention via legacy identification, and the negative indirect effect of psychological contract violation on boomerang intention via legacy identification are all stronger when there is a cooperative relationship. Theoretical and practical implications are discussed.

Vacancy-Assisted Growth Mechanism of Multilayer Hexagonal Boron Nitride on a Fe2B Substrate.

The controllable synthesis of large-area and uniform hexagonal boron nitride (h-BN) films has been recently achieved on metal-boron alloy catalysts with the use of N2 feedstock, representing important progress in an economic and environmentally friendly process. However, the systematic investigation of the growth mechanism is still lacking, which impedes the further development of this method. In this work, on the basis of density functional theory (DFT) calculations and experiments, we reveal the vacancy-assisted growth mechanism of h-BN on Fe2B substrate. It is found that B vacancies created by the formation of BN dimers play important roles in the migration of B and N atoms near the catalyst surface. The diffusions of B and N atoms in the Fe2B substrate need to overcome energy barriers of only less than 1.5 eV, which enables abundant dissolution of N atoms near the catalytic surface. Moreover, we found the critical barrier for h-BN growth is in the nucleation stage, which is ∼2 eV. These advantages enable the synthesis of h-BN at a low temperature of 700 K in our experiments. This vacancy-assisted growth of h-BN films on Fe2B substrates is beneficial to the wafer-scale fabrication of multilayer materials, paving the way to potential applications in two-dimensional electronic and optoelectronic devices.

Catalyst-Free Growth of Two-Dimensional BCxN Materials on Dielectrics by Temperature-Dependent Plasma-Enhanced Chemical Vapor Deposition.

Traditional methods to prepare two-dimensional (2D) B-C-N ternary materials (BCxN), such as chemical vapor deposition (CVD), require sophisticated experimental conditions such as high temperature, delicate control of precursors, and postgrowth transfer from catalytic substrates, and the products are generally thick or bulky films without the atomically mixed phase of B-C-N, hampering practical applications of these materials. Here, for the first time, we develop a temperature-dependent plasma-enhanced chemical vapor deposition (PECVD) method to grow 2D BCxN materials directly on noncatalytic dielectrics at low temperature with high controllability. The C, N, and B compositions can be tuned by simply changing the growth temperature. Thus, the properties of the as-made materials including band gap and conductivity are modulated, which is hardly achieved by other methods. A 2D hybridized BC2N film with a mixed BC2N phase is produced, for the first time, with a band gap of about 2.3 eV. The growth temperature is 580-620 °C, much lower than that of traditional catalytic CVD for growing BCxN. The product has a p-type conducting property and can be directly applied in field-effect transistors and sensors without postgrowth transfer, showing great promise for this method in future applications.

Shaping the Future of Solid-State Electrolytes through Computational Modeling.

Advances and progress in computational research that aims to understand and improve solid-state electrolytes (SSEs) are outlined. One of the main challenges in the development of all-solid-state batteries is the design of new SSEs with high ion diffusivity that maintain chemical and phase stability and thereby provide a wide electrochemical stability window. Solving this problem requires a deep understanding of the diffusion mechanism and properties of the SSEs. A second important challenge is the development of an understanding of the interface between the SSE and the electrode. The role of molecular simulations and modeling in dealing with these challenges is discussed, with reference to examples in the literature. The methods used and issues considered in recent years are highlighted. Finally, a brief outlook about the future of modeling in studying solid-state battery technology is presented.

Nitrogen cluster doping for high-mobility/conductivity graphene films with millimeter-sized domains.

Directly incorporating heteroatoms into the hexagonal lattice of graphene during growth has been widely used to tune its electrical properties with superior doping stability, uniformity, and scalability. However the introduction of scattering centers limits this technique because of reduced carrier mobilities and conductivities of the resulting material. Here, we demonstrate a rapid growth of graphitic nitrogen cluster-doped monolayer graphene single crystals on Cu foil with remarkable carrier mobility of 13,000 cm2 V-1 s-1 and a greatly reduced sheet resistance of only 130 ohms square-1. The exceedingly large carrier mobility with high n-doping level was realized by (i) incorporation of nitrogen-terminated carbon clusters to suppress the carrier scattering and (ii) elimination of all defective pyridinic nitrogen centers by oxygen etching. Our study opens up an avenue for the growth of high-mobility/conductivity doped graphene with tunable work functions for scalable graphene-based electronic and device applications.