Boosting low-temperature selective catalytic reduction of NO_(x)with NH_(3)of V_(2)O_(5)/TiO_(2)catalyst via B-doping

A series of B-doped V_(2)O_(5)/TiO_(2) catalysts has been prepared the by sol-gel and impregnation methods to investigate the influence of B-doping on the selective catalytic reduction(SCR)of NOxwith NH_(3).X-ray diffraction,Brunauer-Emmett-Teller specific surface area,scanning electron microscope,X-ray photoelectron spectroscopy,temperature-programmed reduction of H_(2) and temperature-programmed desorption of NH_(3)technology were used to study the effect of the B-doping on the structure and NH_(3)-SCR activity of V_(2)O_(5)/TiO_(2) catalysts.The experimental results demonstrated that the introduction of B not only improved the low-temperature SCR activity of the catalysts,but also broadened the activity temperature window.The best SCR activity in the entire test temperature range is obtained for VTiB_(2.0) with 2.0%doping amount of B and the NO_(x) conversion rate is up to 94.3%at 210℃.The crystal phase,specific surface area,valence state reducibility and surface acidity of the active components for the as-prepared catalysts are significantly affected by the B-doping,resulting in an improved NH_(3)-SCR performance.These results suggest that the V_(2)O_(5)/TiO_(2) catalysts with an appropriate B content afford good candidates for SCR in the low temperature window.

Study of the response of 10B-doped MCP to wide-energy range neutrons from eV to MeV

Neutron-sensitive microchannel plates(nMCPs)have applications in neutron detection,including energy spectrum measurements,neutron-induced cross sections,and neutron imaging.10B-doped MCPs(B-MCPs)have attracted significant attention owing to their potential for exhibiting a high neutron detection efficiency over a large neutron energy range.Good spatial and temporal resolutions are useful for neutron energy-resolved imaging.However,their practical applications still face many technical challenges.In this study,a B-MCP with 10 mol%10B was tested for its response to wide-energy neutrons from eV to MeV at the Back-n white neutron source at the China Spallation Neutron Source.The neutron detection efficiency was calibrated at 1 eV,which is approximately 300 times that of an ordinary MCP and indicates the success of 10 B doping.The factors that caused the reduction in the detection efficiency were simulated and discussed.The neutron energy spectrum obtained using B-MCP was compared with that obtained by other measurement methods,and showed very good consistency for neutron energies below tens of keV.The response is more complicated at higher neutron energy,at which point the elastic and nonelastic reactions of all nuclides of B-MCP gradually become dominant.This is beneficial for the detection of neutrons,as it compensates for the detection efficiency of B-MCP for high-energy neutrons.

CO_(2)methanation boosted by support-size-dependent strong metal-support interaction and B-O-Ti component

Strong metal-support interaction(SMSI)has a great impact on the activity and selectivity of heterogeneous catalysts,which was usually adjusted by changing reduction temperature or processing catalyst in different atmosphere.However,few researches concentrate on modulating SMSI through regulating the structure of the support.Herein,we show how changing the surface environment of the anatase TiO_(2)(B–TiO_(2))can be used to modulate the SMSI.The moderate TiOx overlayer makes the Ni metal highly dispersed on the high specific surface area of support,resulting in a substantially enhanced CO_(2)methanation rate.Besides,a novel phenomenon was observed that boron dopants promote the for-mation of the B–O–Ti interface site,enhancing the catalytic performance of CO_(2)hydrogenation.DFT calculations confirm that the B–O–Ti structure facilitates the activation of CO_(2)and further hydrogenation to methane.

B-doped and La_(4)NiLiO_(8)-coated Ni-rich cathode with enhanced structural and interfacial stability for lithium-ion batteries

Ni-rich layered oxides are considered promising cathodes for advanced lithium-ion batteries(LIBs)in the future,owing to their high capacity and low cost.However,the issues on structural and interfacial stability of Ni-rich cathodes still pose substantial obstacles in the practical application of advanced LIBs.Here,we employ a one-step method to synthesize a B-doped and La_(4)NiLiO_(8)-coated LiNi_(0.82)5Co_(0.115)Mn_(0.06)O_(2)(BL-1)cathode with reliable structure and interface,for the first time.The La_(4)NiLiO_(8)coating layer can prevent cathodes from electrolyte assault and facilitate Li+diffusion kinetics.Moreover,B-doping can effectively restrain the pernicious H_(2)-H_(3) phase transition and adjust the orientation of primary particles to a radial alignment,which is obstructive to the arise of microcracks induced by the change of anisotropic volume.Specifically,when tested in pouch cells,the BL-1 cathode exhibits outstanding capacity retention of 93.49%after 500 cycles at 1 C.This dual-modification strategy dramatically enhances the stability of the structure and interface for Ni-rich cathode materials,consequently accelerating the commercialization process of high-energy–density LIBs.

Effective enhancement of the electrochemical properties for Na_(2)FeP_(2)O_(7)/C cathode materials by boron doping

In recent years,the composite materials based on polyanionic frameworks as secondary sodium ion battery electrode material have been developed in large-scale energy storage applications due to its safety and stability.The Na_(2)FeP_(2)O_(7)/C(theoretical capacity 97 mA·h·g^(-1))is recognized as optimum Na-storage cathode materials with a trade-off between electrode performance and cost.In the present work,The Na_(2)FeP_(2)O_(7)/C and boron-doped Na_(2)FeP_(2-x)BxO_(7)/C composites were synthesized via a novel method of liquid phase combined with high temperature solid phase.The non-metallic element B doping not only had positive influence on the crystal structure stability,Na+diffusion and electrical conductivity of Na_(2)FeP_(2)O_(7)/C,but also contributed to the high-value recycling of B element in waste borax.The structure and electrochemical properties of the cathode material were investigated via X-ray diffraction(XRD),scanning electron microscopy(SEM),The X-ray photoelectron spectroscopy(XPS),electrochemical impedance spectroscopy(EIS),cyclic voltammetry(CV),and charge/discharge cycling.The results showed that different amounts of boron doping had positive effects on the structure and electrochemical properties of the material.The initial charge/discharge performances of born doped materials were improved in comparison to the bare Na_(2)FeP_(2)O_(7)/C.The cycle performance of the Na_(2)FeP_(1.95)B_(0.05)O_(7)/C showed an initial reversible capacity of 74.8 mA·h·g^(-1) and the high capacity retention of 91.8%after 100 cycles at 1.0 C,while the initial reversible capacity of the bare Na_(2)FeP_(2)O_(7)/C was only 66.2 mA·h·g^(-1).The improvement of apparent Na+diffusion and electrical conductivity due to B doping were verified by the EIS test and CVs at various scan rate.The experimental results from present work is useful for opening new insight into the contrivance and creation of applicable sodium polyanionic cathode materials for high-performance.

Boron modulating electronic structure of FeN4C to initiate high-efficiency oxygen reduction reaction and high-performance zinc-air battery

The biggest challenge is to develop a low cost and readily available catalyst to replace expensive commercial Pt/C for efficient electrochemical oxygen reduction reaction(ORR).In this research,closo-[B_(12)H_(12)]^(2−)and 1,10-phenanthroline-iron complexes were introduced into the porous metal-organic framework by impregnation method,and further annealing treatment achieved the successful anchoring of single-atom-Fe in B-doped CN Matrix(FeN4CB).The ORR activity of FeN4CB is comparable to the widely used commercial 20 wt%Pt/C.Where the half-wave potential(E_(1/2))in alkaline medium up to 0.84 V,and even in the face of challenging ORR in acidic medium,the E_(1/2)of ORR driven by FeN4CB is still as high as 0.81 V.When FeN4CB was used as air cathode,the open circuit voltage of Zn-air battery reaches 1.435 V,and the power density and specific capacity are as high as 177 mW cm^(−2)and 800 mAh g_(Zn)^(−1)(theoretical value:820 mAh g_(Zn)^(−1)),respectively.The dazzling point of FeN4CB also appears in the high ORR stability,whether in alkaline or acidic media,E_(1/2)and limiting current density are still close to the initial value after 5000 times cycles.After continuously running the charge-discharge test for 220 h,the charge voltage and discharge voltage of the rechargeable zinc-air battery with FeN4CB as the air cathode maintained the initial state.Density functional theory calculations reveals that introducing B atom to Fe–N4–C can adjust the electronic structure to easily break O=O bond and significantly reduce the energy barrier of the rate-determining step resulting in an improved ORR activity.

Boron-doping induced lithophilic transition of graphene for dendrite-free lithium growth

Li metal,possessing advantages of high theoretical specific capacity and low electrochemical potential,is regarded as the most promising anode material for next-generation batteries.However,despite decades of intensive research,its practical application is still hindered by safety hazard and low Coulombic efficiency,which is primarily caused by dendritic Li deposition.To address this issue,restraining dendrite growth at the nucleation stage is deemed as the most effective method.By utilizing the difference of electronegativity between boron atoms and carbon atoms,carbon atoms around boron atoms in boron-doped graphene(BG)turn into lithiophilic sites,which can enhance the adsorption capacity to Li^(+)at the nucleation stage.Consequently,an ultralow overpotential of 10 mV at a current density of 0.5 mA/cm^(2) and a high average Coulombic efficiency of 98.54%over more than 140 cycles with an areal capacity of 2 mAh/cm^(2) at a current density of 1 m A/cm^(2) were achieved.BG-Li|LiFePO_(4) full cells delivered a long lifespan of480 cycles at 0.5 C and excellent rate capability.This work provides a novel method for rational design of dendrite-free Li metal batteries by regulating nucleation process.

Hazy Backside Gettering with a-Si: H Film

Hazy backside gettering of boron-doped <111> siljcon wafer with a-Si: H film deposited by rf glow discharge technique (rf-GD) has been investigated by SEM, optical microscope and preferential etching tech- lique. lt is evident that the deposited film can effectively getter the haze after annealing at l l00℃in wet oxy- len ambient for 120 min. The pre-crystallization annealing at 650℃ in argon ambient for 10 min enhances the gettering effectiveness. The low temperature(200～300℃) process of growing extrinsic gettering film reduces the processing contamination.

Facile synthesis and superior photocatalytic and electrocatalytic performances of porous B-doped g-C_3N_4 nanosheets

As a low-cost visible-light-driven metal-free catalyst, graphitic carbon nitride(g-CN) has attracted increasing attention due to its wide applications for solar energy conversion, environmental purification,and organic photosynthesis. In particular, the catalytic performance of g-CNcan be easily modulated by modifying morphology, doping, and copolymerization. Simultaneous optimization, however, has little been achieved. Herein, a facile one-pot strategy is developed to synthesize porous B-doped g-CNnanosheets by using HBOand urea as the precursor during thermal polymerization. The resultant B-doped g-CNnanosheets retain the original framework of bulk g-CN, while induce prominently enhanced visible light harvesting and narrowing band gap by 0.32 eV compared to pure g-CN. Moreover, the adsorption capacity and photodegradation kinetics of methylene blue(MB) under visible light irradiation over B-doped g-CNnanosheets can be improved by 20.5 and 17 times, respectively. The synthesized porous B-doped g-CNnanosheets also exhibit higher activities than pure g-CNas bifunctional electrocatalyst for both oxygen evolution reaction(OER) and oxygen reduction reaction(ORR). The enhanced catalyst performance of porous B-doped g-CNnanosheets stems from the strong synergistic effect originating from the larger exposed active sites generated by the exfoliation of g-CNinto nanosheets and the porous structure, as well as the better conductivity owing to B-doping. This work provides a simple, effective, and robust method for the synthesis of g-CN-based nanomaterial with superior properties to meet the needs of various applications.

Bimetallic oxide coupled with B-doped graphene as highly efficient electrocatalyst for oxygen evolution reaction

Developing electrocatalysts with high performance and low cost for the oxygen evolution reaction(OER)is of great importance for fabricating renewable energy storage and conversion devices.Here,a series of boron-doped graphene(BG)-supported bimetallic oxides of Co and Ni were obtained and served as OER electrocatalysts.Surprisingly,the annealed Co-Ni-Ox/BG with a Co/Ni ratio of 1:1 exhibits high performance toward oxygen evolution in alkaline electrolyte.The overpotential is only 310 mV at the current density of 10 mA cm-2,superior to many mono-metallic oxides reported before,and even comparable to the commercial RuO2.The regulation of charge distribution in bimetallic oxides and the strong synergistic coupling effects together contribute to the superior electrocatalytic performance of the Co-Ni-Ox/BG toward OER.This study also offers several effective ways to design high-performance OER electrocatalysts for water splitting.

Highly exposed NiFeO_(x) nanoclusters supported on boron doped carbon nanotubes for electrocatalytic oxygen evolution reaction

The development of efficient and cost-effective electrocatalysts for oxygen evolution reaction(OER) is crucial for the overall water splitting. Herein, we prepared a highly exposed NiFeO_(x) ultra-small nanoclusters supported on boron-doped carbon nonotubes catalyst, which achieves a 10 mA/cm^(2) anodic current density at a low overpotential of 213 mV and the Tafel slope of 52 mV/dec in 1.0 mol/L KOH, superior to the pristine NiFeO_(x)-CNTs and other state-of-the-art OER catalysts in alkaline media. A combination study(XPS, sXAS and XAFS) verifies that the local atomic structure of Ni and Fe atoms in the nanoclusters are similar to NiO and Fe_(2)O_(3), respectively, and the B atoms which are doped into the crystal lattice of CNTs leads to the optimization of Ni 3d egorbitals. Furthermore, in-situ X-ray absorption spectroscopies reveal that the high valence state of Ni atoms are served as the real active sites. This work highlights that the precise control of highly exposed multicomponent nanocluster catalysts paves a new way for designing highly efficient catalysts at the atomic scale.

Boron-doped Covalent Triazine Framework for Efficient CO_(2) Electroreduction

Converting CO_(2) into chemicals with electricity generated by renewable energy is a promising way to achieve the goal of carbon neutrality. Carbon-based materials have the advantages of low cost, wide sources and environmental friendliness. In this work, we prepared a series of boron-doped covalent triazine frameworks and found that boron doping can significantly improve the CO selectivity up to 91.2% in the CO_(2) electroreduction reactions(CO_(2)RR). The effect of different doping ratios on the activity by adjusting the proportion of doped atoms was systematically investigated. This work proves that the doping modification of non-metallic materials is a very effective way to improve their activity, and also lays a foundation for the study of other element doping in the coming future.

Electronic structure and optical property of boron doped semiconducting graphene nanoribbons

We present a system study on the electronic structure and optical property of boron doped semiconducting graphene nanoribbons using the density functional theory. Energy band structure, density of states, deformation density, Mulliken popular and optical spectra are considered to show the special electronic structure of boron doped semiconducting graphene nanoribbons. The C-B bond form is discussed in detail. From our analysis it is concluded that the Fermi energy of boron doped semiconducting graphene nanoribbons gets lower than that of intrinsic semiconducting graphene nanoribbons. Our results also show that the boron doped semiconducting graphene nanoribbons behave as p-type semiconducting and that the absorption coefficient of boron doped armchair graphene nanoribbons is generally enhanced between 2.0 eV and 3.3 eV. Therefore, our results have a great significance in developing nano-material for fabricating the nano-photovoltaic devices.