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Molybdenum trioxide (MoO3) has been widely studied in the energy storage field due to its various phase states and unique structural advantages. Among them, lamellar α-phase MoO3 (α-MoO3) and tunnel-like h-phase MoO3 (h-MoO3) have attracted much attention. In this study, we demonstrate that vanadate ion (VO3-) can transform α-MoO3 (a thermodynamically stable phase) to h-MoO3 (a metastable phase) by altering the connection of [MoO6] octahedra configurations. h-MoO3 with VO3- inserted (referred to as h-MoO3-V) as the cathode material for aqueous zinc ion batteries (AZIBs) exhibits excellent Zn2+ storage performances. The improvement in electrochemical properties is attributed to the open tunneling structure of the h-MoO3-V, which offers more active sites for Zn2+ (de)intercalation and diffusion. As expected, the Zn//h-MoO3-V battery delivers specific capacity of 250 mAh·g-1 at 0.1 A·g-1 and rate capability (73% retention from 0.1 to 1 A·g-1, 80 cycles), well exceeding those of Zn//h-MoO3 and Zn//α-MoO3 batteries. This study demonstrates that the tunneling structure of h-MoO3 can be modulated by VO3- to enhance the electrochemical properties for AZIBs. Furthermore, it provides valuable insights for the synthesis, development and future applications of h-MoO3.
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Mung bean starch (MBS) has a strong potential to be used as food packages. However, preparing tough and uniform MBS films via industrial casting remains challenging due to the high viscosity of MBS slurry. Herein, MBS was modified by using dielectric barrier discharge cold plasma (CP) in an attempt to decrease its viscosity and improve the film-forming properties. Results indicated that CP with an applied power of 120 W for 5 min decreased the peaking viscosity of MBS slurry from 2936.5 to 466.3 cP. Moreover, CP treatment simultaneously modified the crystallinity (20.2%-16.7%), amylose content (30.5%-44.3%), and short-range orders (1.04-0.85). CP also broke the protective envelope of MBS granules. Further, the film-forming properties of MBS were investigated. It was observed that CP-modified MBS film casts exhibited uniform morphology, higher tensile strength (6.6-9.6 MPa), and improved thermal stability (89.0-100.8°C) compared with the untreated MBS film. The study indicates that the CP can be used as a green and facile technology to improve the properties of MBS films resulting in an efficient food packing material.
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Fabaceae , Gases em Plasma , Vigna , Amido , ViscosidadeRESUMO
Under dry-hot valley climates, Conyza blinii (also known as Jin Long Dan Cao), suffers from nocturnal low-temperature stress (LTS) during winter. Here, to investigate the biological significance of terpenoid metabolism during LTS adaptation, the growth state and terpenoid content of C. blinii under different LTS were detected, and analyzed with the changes in phytohormone. When subjected to LTS, the results demonstrated that the growth activity of C. blinii was severely suppressed, while the metabolism activity was smoothly stimulated. Meanwhile, the fluctuation in phytohormone content exhibited three different physiological stages, which are considered the stress response, signal amplification, and stress adaptation. Furthermore, drastic changes occurred in the distribution and accumulation of terpenoids, such as blinin (diterpenoids from MEP) accumulating specifically in leaves and oleanolic acid (triterpenoids from MVA) accumulating evenly and globally. The gene expression of MEP and MVA signal transduction pathways also changes under LTS. In addition, a pharmacological study showed that it may be the ABA-SA crosstalk driven by the LTS signal, that balances the metabolic flux in the MVA and MEP pathways in an individual manner. In summary, this study reveals the different standpoints of ABA and SA, and provides a research foundation for the optimization of the regulation of terpenoid metabolic flux within C. blinii.
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The design of highly dispersed active sites of hollow materials and unique contact behavior with the components to be catalyzed provide infinite possibilities for exploring the limits of catalyst capacity. In this study, the synthesis strategy of highly open 3-dimensional frame structure Prussian blue analogues (CoFe-PBA) was explored through structure self-transformation, which was jointly guided by template mediated epitaxial growth, restricted assembly and directional assembly. Additionally, good application prospect of CoFe-PBA as combustion catalyst was discussed. The results show that unexpected thermal decomposition behavior can be achieved by limiting AP(ammonium perchlorate) to the framework of CoFe-PBA. The high temperature decomposition stage of AP can be advanced to 283.6 °C and the weight loss rate can reach 390.03% min-1 . In-situ monitoring shows that CoFe-PBA can accelerate the formation of NO and NO2 . The calculation of reaction kinetics proved that catalytic process was realized by increasing the nucleation factor. On this basis, the catalytic mechanism of CoFe-PBA on the thermal decomposition of AP was discussed, and the possible interaction process between AP and CoFe-PBA during heating was proposed. At the same time, another interesting functional behavior to prevent AP from caking was discussed.
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To improve the stability and bioavailability of the delivered hydrophobic nutrients, the zein-based delivery system was modified by alginate oligosaccharide (AOS), cold plasma (CP) treatments, and synergistically. The digestive behavior of each was investigated in an INFOGEST static in vitro digestion model. The results showed that AOS and CP treatments and their synergistic effects improved the dispersion and stability of the delivery system, leading to a more concentrated particle size distribution and higher particle surface charge. Both CP treatments and AOS increased the release rate of Curcumin (Cur) at small intestine (11.8 % to 20.5 % and 11.8 % to 24.64 %, respectively), and the synergistic effect was higher (11.8 % to 43.84 %). The wall material modified showed a higher encapsulation efficiency of Cur (52.83 % to 85.17 %). Cur release rate measurements showed that the wall material modified could have a positive effect on the slow release of Cur. SDS-page electrophoresis revealed that the slow release was due to the enhanced resistance of wall material to digestive fluids. Thus, treatment with AOS and CP treatments, and the synergism are suitable for modifying zein-based delivery systems for the encapsulation, stabilization, and slow release of hydrophobic nutrients during digestion in the field of functional foods.
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Curcumina , Nanopartículas , Gases em Plasma , Zeína , Nanopartículas/química , Alginatos/química , Disponibilidade Biológica , Zeína/química , Curcumina/farmacologia , Curcumina/química , Tamanho da PartículaRESUMO
Calcium has limited bioavailability because of the formation of calcium phosphate deposits in the gastrointestinal tract. In this study, we prepared a dextran-casein phosphopeptide (CPP)-Ca2+ delivery system and evaluated for Ca2+ binding mechanism, structure, stability, and sustained release of Ca2+ and assessed inhibition of calcium phosphate precipitation. The results revealed that Ca2+ binds to dextran-CPP through the phosphate, carboxyl, and amino groups and forms crystal clusters. Furthermore, compared with single polymer CPP-Ca2+ conjugates, copolymer dextran-CPP-Ca2+ conjugates exhibited improved stability at various conditions (pH, temperature, and coexisting food), efficiently reduced the calcium phosphate precipitation, and improved sustained-release of Ca2+. Collectively, dextran-CPP-Ca2+ conjugates can be an efficient Ca2+ delivery system.
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Cálcio , Dextranos , Cálcio/química , Caseínas/química , Fosfatos de Cálcio , Fosfopeptídeos/químicaRESUMO
Aqueous zinc-ion batteries (AZIBs) are regarded as attractive candidates for next-generation energy storage devices. Among various cathode materials, V2O5·nH2O (VOH) possesses a high theoretical capacity but poor cycle stability due to the susceptibility of its open structure to damage by the quick shuttling of Zn2+. Herein, the structural stability of VOH is directly improved by wrapping polyaniline (PANI) on the VOH nanobelts (VOH@PANI). As a cathode material for AZIBs, the VOH nanobelts@PANI core-shell structures exhibit an outstanding cycle stability of 98% after 2000 cycles at 2 A g-1. The improved conductivity and additional energy storage contribution of the PANI endow VOH@PANI with a specific capacity as high as 440 mAh g-1 at 0.1 A g-1, substantially higher than pure VOH (291 mAh g-1). At the same time, high energy and power densities of 349 Wh kg-1 and 3347 W kg-1 are achieved. This work not only demonstrates that p-type doped PANI coatings on VOH can boost the Zn2+ storage of VOH, but also provides a novel method to enhance cathode materials for high electrochemical performance.
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Gelation and structure of oat starch significantly affect qualities of whole oat flour noodles. During extrusion, the structure of noodles is loose, resulting in high cooking loss and poor texture. Therefore, oat noodles were treated with high temperature, high humidity (HTH), and cold storage (CS), and their structure and qualities were analyzed. The results showed that compared with CS, HTH could reduce the cooking loss of noodles from 10.12% to 6.13%, increase the hardness (65.59 g) and chewiness (20.67) of noodles, and effectively improve the sensory quality of noodles. The change in texture and sensory of noodles was due to HTH by accelerating the retrogradation of starch in noodles, promoting the cross-linking of starch molecules to form an ordered structure, causing an increase in the ordered degree and crystallinity of starch and making the structure of noodles denser. It made the mobility of water in the noodles decrease, and more tightly bound water was transformed into weakly bound water and free water. HTH can be applied to industrial production of whole oat flour noodles. This study could effectively guide the production of high-quality whole oat flour noodles without any food additives.
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Avena , Farinha , Farinha/análise , Avena/metabolismo , Temperatura , Umidade , Amido/química , Culinária , ÁguaRESUMO
Aqueous ammonium-ion energy storage systems have recently gained continuous attention owing to the advantages of sustainability and environmental-friendliness in the grid-scale application. However, ammonium-ion supercapacitors are still in their infancy, and it is of great challenge in developing suitable materials for application in wearable energy storage devices. Herein, we develop a vanadium oxide hydration (V2O5·nH2O)/reduced graphene oxide (rGO) composite film (denoted as VGF) as a free-standing paper-like electrode for ammonium-ion storage, where V2O5·nH2O shows an expanded interlayer spacing and is sandwiched by rGO through chemical bonds. As a result, the designed VGF exhibits a capacitance of 600F·g-1 at 0.2 A·g-1 and good cyclability of over 10,000 cycles with a retention of 93 % using PVA/NH4Cl gel electrolyte. Meanwhile, the ammonium-ion storage mechanism in VGF electrode is further verified to be dominated by the intercalation pseudocapacitance and electric double-layer capacitance. Furthermore, the quasi-solid-state symmetric supercapacitor (SSC) has been also assembled to assess the feasibility of practical applications in wearable devices. As expected, the SSC possesses an areal capacitance of 241 mF·cm-2 at 0.1 mA·cm-2 (0.82 Wh·m-2 at 0.09 W·m-2) and an excellent cyclability of 20,000 cycles with a retention of 92 %, which is comparable to that achieved in the vanadium oxides powder-made electrodes and the SSC made of. Together with the excellent flexibility and feasibility of parallel/series combination, the VGF SSC devices shows great possibility for the applications in wearable devices, which further proves the great potential of this designed VGF free-standing electrode for ammonium-ion storage.
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In order to investigate the cause of accumulation of the inorganic suspended solid (ISS) in biochemical tank for wastewater treatment plant (WWTP) in recent years, the influent quality of one WWTP in Chongqing was monitored in one year, and the removal efficiency of ISS during the pretreatment process was studied. Results showed that the low removal efficiency of ISS (<7%) was ascribed to the weak removal efficiency of sand in the grit chamber. The primary sedimentation tank showed a good removal efficiency of ISS up to 69% and also had a good removal efficiency of COD up to 70%. The annual variation rule of MLVSS/MLSS for mixed liquor varied in contrast to the influent quality, ranging from 0.24 to 0.57, much lower than the normal value of 0.7. In order to maintain the normal function of activated sludge, it is necessary to retain the primary sedimentation tank to remove ISS.
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Esgotos , Purificação da Água , Reatores Biológicos , Areia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Purificação da Água/métodosRESUMO
Burning rate of solid propellants can be effectively improved by adding catalysts and using smaller size ammonium perchlorate (AP). Although few reports, the exploration of changing the size of AP primary particles by catalysts is of great significance for improving combustion performance. Here, taking Co-bipy as an example, the potential advantages of such materials as AP decomposition catalysts are reported. Due to the existence of NO3 - combined with oxygen rich environment provided by AP, the structural self-transformation from micronrods to nanoparticles can be quickly realized during the heating process. More importantly, when Co-bipy decomposes, it can play the role of "scalpel" and in situ cut AP particles. Results show that high-temperature decomposition of Co-bipy/AP occurs at 305.8 °C, which is 137.5 °C lower than that of pure AP. Catalytic mechanism is discussed by in situ IR and TG-IR, CoO can effectively increase the content of reactive oxygen species and weaken the N-H bond, realizing the rapid oxidation of NH3 . Eventually, the behavior of Co-bipy cutting AP particles is tested. This interesting catalyst structure self-transformation behavior can not only realize the influence on AP, but also perform a positive function in the combustion process of solid propellants, such as opening the adhesive AP interface.
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Layered vanadium-based materials are considered to be great potential electrode materials for aqueous Zn-ion batteries (AZIBs). The improvement of the electrochemical properties of vanadium-based materials is a hot research topic but still a challenge. Herein, a composite of Zn-ion pre-intercalated V2O5·nH2O combined with reduced graphene oxide (ZnVOH/rGO) is synthesized by a facile hydrothermal method and it shows improved Zn-ion storage. ZnVOH/rGO delivers a capacity of 325 mAh·g-1 at 0.1 A·g-1, and this value can still reach 210 mAh·g-1 after 100 cycles. Additionally, it exhibits 196 mAh·g-1 and keeps 161 mAh·g-1 after 1200 cycles at 4 A·g-1. The achieved performances are much higher than that of ZnVOH and VOH. All results reveal that Zn2+ as "pillars" expands the interlayer distance of VOH and facilitates the fast kinetics, and rGO improves the electron flow. They both stabilize the structure and enhance efficient Zn2+ migration. All findings demonstrate ZnVOH/rGO's potential as a perspective cathode material for AZIBs.
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A kind of cadmium sulfide (CdS) nanocomposite with different crystalline phases was grown on the surface of H-mordenite zeolite (HMOR) by a chemical liquid-phase co-precipitation method. In this work, 2 wt% CdS@HMOR photocatalytic material with the coexistence phase (hexagonal phase and cubic phase) of cadmium sulfide was grown on the surface of HMOR by controlling the reaction temperature and ammonia concentration. Photocatalytic degradation of methylene blue (MB) was used as an index to detect the photocatalytic performance of materials. The results indicated that the photocatalytic degradation efficiency of the system with HMOR was significantly improved in comparison to that without HMOR (CdS, 40.34%, 0.2578 h-1). It was found that 2 wt% CdS@HMOR had the best photocatalytic activity. The degradation rate of MB was 84.15% in 2 h, and the degradation rate constant was 0.8884 h-1. When 1.5 ml H2O2 was introduced into the system, the degradation rate of MB was increased to 98.98%, and the degradation rate constant was 1.9976 h-1. SEM, HRTEM, PL, EIS and photocurrent showed that the cubic and hexagonal phases of CdS were in contact with each other on the HMOR surface, forming a good electron transport. By XRD, XPS and SEM tests, the results of materials after four cycles of reactions showed that the structure of the 2 wt% CdS@HMOR was still stable. Therefore, HMOR may provide a good support for CdS, and the synergistic effect between them is beneficial for the occurrence of photocatalytic reactions. HMOR can act as an electron receptor to inhibit the recombination of carriers. The homo-junction between different phases of CdS on the surface of HMOR is beneficial to the separation of photo-induced carriers. These results indicate that the construction of phase heterojunctions on zeolites and the synergism among them are a method for improving the photocatalytic activity.
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Possessing a 2D zinc-ion transport channel, layered vanadium oxides have become good candidates as cathode materials for aqueous rechargeable zinc-ion batteries (ARZIBs). Tuning the lamellar structure of vanadium oxides to enhance their zinc-ion storage is a great challenge. In the present study, we proposed and investigated a "co-intercalation mechanism" in which Mg2+ and polyaniline (PANI) were simultaneously intercalated into the layers of hydrated V2O5 (MgVOH/PANI) by a one-step hydrothermal method. Inorganic-organic co-intercalation could tune the layer spacing of VOH, and this combination played a synergistic role in enhancing the zinc-ion storage in MgVOH/PANI. It showed an extremely large layer spacing of 14.2 Å, specific capacity of up to 412 mA h g-1 at 0.1 A g-1, and the capacity retention rate could reach 98% after 1000 cycles. PANI itself has a zinc-storage capacity, and Mg2+ intercalated with PANI can improve the conductivity of the material and enhance its stability. Further first-principles calculations clearly revealed the structural changes and improved electrochemical performance of vanadium oxides. This method of inorganic and organic co-regulation of the VOH structure opens a new strategy for tuning the lamellar structure of layered materials to boost their electrochemical performances.
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A facile novel method of alkali etching was proposed to enhance the application of metal-silicates in supercapacitors. First, 3D N, S, P-doped C-zinc-silicate (C-ZnSi), and C-manganese-silicate (C-MnSi) were derived from calcined green algaes (GAs) in a N2 atmosphere. Second, the synthesized products were soaked in a 3.0 M NaOH aqueous solution for alkali etching (soaked for 6, 12 and 24 h) to obtain the etching metal silicates (e-C-ZnSi and e-C-MnSi). This method can yield a higher specific surface area and more pores, and this in turn can improve the electrochemical performance. In the three-electrode system, e-C-ZnSi and e-C-MnSi, which were soaked in NaOH solution for 12 h, exhibited the highest specific capacitances and cycling performance. Solid-state hybrid supercapacitor (HSC) devices were manufactured using C-MSi, e-C-MSi (M = Zn and Mn), and activated carbon (AC) (denoted as C-MSi//AC and e-C-MSi//AC). In the two-electrode system, the e-C-MSi//AC HSC devices exhibited higher areal specific capacitances and energy densities and better cycle performance than those of C-MSi//AC, especially e-C-MSi//AC-12 h HSC devices, which exhibited the best electrochemical properties. This study demonstrated that the naturally polluted GAs can be used as a reusable silica source for the synthesis of supercapacitors. Furthermore, alkali etching can enhance the electrochemical performance of metal silicates and can be used to prepare electrode materials applied for high-performance supercapacitors.
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To study the influence of different confining pressures on the pore structure and connectivity of high-rank coal, the high-rank raw coal of the Shanxi Xinjing Mine No. 9 coal seam was studied. A low-field nuclear magnetic resonance (LNMR) test system and a vacuum pressurized water saturation system were used to analyze the samples. The T 2 spectra of samples, saturated with water under different confining pressures and containing residual water after centrifugation, were tested. The coal sample pore size distributions, permeabilities, free fluid values, bound fluid values, and other parameters were obtained, and a calculation model of the coal pore connectivity ratio was established. The results were as follows. When the saturated pressures were 5, 10, 15, 20, 25, and 30 MPa, the pore diameters of the coal samples were mainly concentrated in the ranges of 0.00023-0.069 and 1.29-24.09 µm. Among them, micropores (<10 nm) and small pores (10 < 100 nm) account for the main part, mesopores (100 < 1000 nm) were underdeveloped, and relatively few macropores (>1000 nm) and fissures developed. As the confining pressure increased, the coal porosity and connectivity showed a trend of decreasing, then increasing, and finally remaining basically unchanged. The total pore connectivity rates of the coal samples were 37.0-62.6%. The interconnection rates of the micropores, small holes, mesopores, and macropores are 2.90-34.55, 89.09-99.03, 97.09-100, and 100%, respectively. The total pore connectivity followed an exponential functional relationship with permeability, and the critical confining pressure of high-rank coal was 25 MPa. These results provide a scientific basis for the high-pressure water injection of high-rank coal seams.
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We present VoxelTrack for multi-person 3D pose estimation and tracking from a few cameras which are separated by wide baselines. It employs a multi-branch network to jointly estimate 3D poses and re-identification (Re-ID) features for all people in the environment. In contrast to previous efforts which require to establish cross-view correspondence based on noisy 2D pose estimates, it directly estimates and tracks 3D poses from a 3D voxel-based representation constructed from multi-view images. We first discretize the 3D space by regular voxels and compute a feature vector for each voxel by averaging the body joint heatmaps that are inversely projected from all views. We estimate 3D poses from the voxel representation by predicting whether each voxel contains a particular body joint. Similarly, a Re-ID feature is computed for each voxel which is used to track the estimated 3D poses over time. The main advantage of the approach is that it avoids making any hard decisions based on individual images. The approach can robustly estimate and track 3D poses even when people are severely occluded in some cameras. It outperforms the state-of-the-art methods by a large margin on four public datasets including Shelf, Campus, Human3.6M and CMU Panoptic.
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The development of robust, low-cost and efficient oxygen evolution reaction (OER) electrocatalysts, especially non-noble-metal-based OER catalysts, is of great significance and imperative to address the energy crisis, but remain challenging. Herein, a biomass-derived three-dimensional (3D) porous carbon/cobalt silicate (C/Co2SiO4) architecture is developed as a support for loading nickel oxide (NiOx) species to prepare an earth-abundant and non-noble-metal-based NiOx/C/Co2SiO4 electrocatalyst. The NiOx nanoparticles are dispersed on 3D C/Co2SiO4 support and the introduction of NiOx species improves the OER active sites and shows the bimetal (Co, Ni) synergetic effect. The NiOx/C/Co2SiO4 electrocatalyst exhibits the overpotential with 355 mV at 10 mA cm-2, Tafel slope with 40 mV dec-1 and large electrochemical active surface areas (ECSA), which are superior to C/Co2SiO4 support and NiOx. The catalytic properties achieved herein are superior or comparable to most transition metal oxides/hydroxides. The findings reveal that the introduction of NiOx nanoparticles can greatly boost the OER property of C/Co2SiO4 support. This work not only develops a non-noble-metal-based NiOx/C/Co2SiO4 catalyst, but also verifies that the introduction of metal oxide species on biomass-derived 3D C/Co2SiO4 provides a new horizon to explore economical, high-efficient and robust OER catalysts.
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Cobalto , Nanopartículas , Biomassa , Carbono , Níquel , Óxidos , Oxigênio/química , SilicatosRESUMO
Cobalt silicate (CoSi) is a promising electrode material for supercapacitors (SCs) and an electrocatalytic material for the oxygen evolution reaction (OER). How to synthesize cobalt silicate with excellent energy storage and OER properties has not been reported and it is a great challenge for researchers to accomplish it. In this work, we find that the electrochemical properties of CoSi are particularly affected by critical factors during the synthesis process. Three types of CoSi compounds are synthesized using Stöber SiO2 as the self-sacrificing template via a hydrothermal reaction. The CoSi compounds generated from different reaction systems have obvious differences in the macrostate, microscopic morphology, composition and valence, leading to different electrochemical performances for energy storage and OER properties. The findings reveal that the differences (especially valence) among CoSi are determined by the formation of the metal source in the reaction system. The specific capacitance of CoSi-3 obtained from the system with basic salts as the metal source is eight times higher than that of CoSi-1 obtained from the system with coordination compounds as the metal source, whereas CoSi-1 has a greater advantage in electrocatalytic activity. This work provides insight for the synthesis of cobalt silicates applied to energy storage and conversion.
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Oxygen evolution reaction (OER) has drawn ever-increasing attention because of its essential role in various renewable-energy technologies. In spite of tremendous research efforts, developing high-performance OER catalysts at low cost remains a great challenge. Inspired by two earth-abundant elements Fe and Si, herein, we report a Fe-Co2SiO4 composite consisting of well dispersed iron oxide (FeOx) decorated Co2SiO4 hollow nanospheres as an economical and promising OER catalyst. Although Co2SiO4 or FeOx alone has little OER activity, their composite exhibits satisfied performance, that is highly related to geometric effect and bimetal component electronic interactions. The Fe-Co2SiO4 composite exhibits comparable catalytic activity to most of transition mental oxide/hydroxide relevant composites at 10 mA cm-2. It is even 1.6 times higher than commercial RuO2 electrocatalyst at high current density 100 mA cm-2 in alkaline solution. In this work, surface decoration of transition metal silicate provides a new horizon to design high-performance and economical OER catalysts.