Effective ethanol-to-CO_(2) electrocatalysis at iridium-bismuth oxide featuring the impressive negative shifting of the working potential

Since low overpotential for the anodic ethanol oxidation reaction(EOR)can favor the higher output voltage and power of direct ethanol fuel cells(DEFCs),it is critical to design new EOR catalysts with efficient ethanol-to-CO_(2)activity at low applied potentials.Thereby,carbon-supported Ir-Bi_(2)O_(3)(Ir-Bi_(2)O_(3)/C)catalysts with highly dispersive bismuth oxide on the iridium surface are designed and prepared,which can merit splitting the ethanol C–C bond and promoting the oxidation of C1 intermediates at the bifunctional interfaces.The as-obtained Ir-Bi2O3/C catalysts show superior EOR mass activity of up to ca.2250 m A mgIr-1.Moreover,they exhibit the record lowest onset oxidation potentials(0.17–0.22 V vs.RHE)and the peak potential(ca.0.58 V vs.RHE),being 130–300 m V lower than the previous landmark noble metallic catalysts.Furthermore,an apparent C1 pathway faraday efficiency(FEC1)of 28%±5.9%at 0.5 V vs.RHE can be obtained at Ir-Bi_(2)O_(3)/C.This work might provide new insights into the new anodic EOR catalysts for increasing the power of DEFCs.

Conversion of Catalytically Inert 2D Bismuth Oxide Nanosheets for Effective Electrochemical Hydrogen Evolution Reaction Catalysis via Oxygen Vacancy Concentration Modulation

Oxygen vacancies(Vo)in electrocatalysts are closely correlated with the hydrogen evo-lution reaction(HER)activity.The role of vacancy defects and the effect of their concentration,how-ever,yet remains unclear.Herein,Bi2O3,an unfavorable electrocata-lyst for the HER due to a less than ideal hydrogen adsorption Gibbs free energy(ΔGH*),is utilized as a perfect model to explore the func-tion of Vo on HER performance.Through a facile plasma irradia-tion strategy,Bi2O3 nanosheets with different Vo concentrations are fabricated to evaluate the influence of defects on the HER process.Unexpectedly,while the generated oxygen vacancies contribute to the enhanced HER performance,higher Vo concentrations beyond a saturation value result in a significant drop in HER activity.By tunning the Vo concentration in the Bi_(2)O_(3)nanosheets via adjusting the treatment time,the Bi2O3 catalyst with an optimized oxygen vacancy concentration and detectable charge carrier concentration of 1.52×10^(24)cm^(−3)demonstrates enhanced HER performance with an overpotential of 174.2 mV to reach 10 mA cm^(−2),a Tafel slope of 80 mV dec−1,and an exchange current density of 316 mA cm−2 in an alkaline solution,which approaches the top-tier activity among Bi-based HER electrocatalysts.Density-functional theory calculations confirm the preferred adsorption of H*onto Bi2O3 as a function of oxygen chemical potential(ΔμO)and oxygen partial potential(PO2)and reveal that high Vo concentrations result in excessive stability of adsorbed hydrogen and hence the inferior HER activity.This study reveals the oxygen vacancy concentration-HER catalytic activity relationship and provides insights into activating catalytically inert materials into highly efficient electrocatalysts.

Role of Bismuth Oxide in Bi-MCo_2O_4(M=Co,Ni,Cu,Zn) Catalysts for Wet Air Oxidation of Acetic Acid

Two series of cobalt(Ⅲ)\|containing spinel catalysts were prepared by the decomposition of the corresponding nitrates. The catalysts doped with bismuth oxide exhibit a higher activity in the wet air oxidation of acetic acid than those without dopant bismuth oxide. The catalysts were investigated by XRD,TEM,ESR,UV\|DRS and XPS,and the interaction between Co and Bi was studied as well. It has been found that nano\|sized bismuth oxide is paved on the surface of cobalt spinel crystal and the structures of cobalt(Ⅲ)\|containing spinel are still maintained. The shift of the binding energy of Bi\-\{\%4f\%\-\{7/2\}\} is related to the catalytic activity of these catalysts doped with bismuth oxide.

Boosting CO_(2) electroreduction to formate via bismuth oxide clusters

Supported metal(oxide)clusters,with both rich surface sites and high atom utilization efficiency,have shown improved activity and selectivity for many catalytic reactions over nanoparticle and single atom catalysts.Yet,the role of cluster catalysts has been rarely reported in CO_(2)electroreduction reaction(CO_(2)RR),which is a promising route for converting CO_(2)to liquid fuels like formic acid with renewable electricity.Here we develop a bismuth oxide(BiOn)cluster catalyst for highly efficient CO_(2)RR to formate.The BiOn cluster catalyst exhibits excellent activity,selectivity,and stability towards formate production,with a formate Faradaic efficiency of over 90%at a current density up to 500 mA·cm^(−2)in an alkaline membrane electrode assembly electrolyzer,corresponding to a mass activity as high as 3,750 A·gBi−1.The electrolyzer with the BiOn cluster catalyst delivers a remarkable formate production rate of 0.56 mmol·min−1 at a high single-pass CO_(2)conversion of 44%.Density functional theory calculations indicate that Bi4O_(3)cluster is more favorable for stabilizing the HCOO^(*)intermediate than Bi(001)surface and single site BiC_(4)motif,rationalizing the improved formate production over the BiOn cluster catalyst.This work highlights the great importance of cluster catalysts in activity and selectivity control in electrocatalytic CO_(2)conversion.

Visible light photocatalytic bismuth oxide coatings are effective at suppressing aquatic cyanobacteria and degrading free-floating genomic DNA

Access to safe drinking water free from microbial pollution is an issue of global concern. The use of photocatalytic thin films in water treatment has focused on titanium dioxide, which requires UV-activation, proving a potential barrier to upscaling and implementation in the real world. Visible-light-activated photocatalytic thin films, such as bismuth oxide, have recently been shown to have antimicrobial properties. However, more understanding of the photocatalytic effect on the microbial population in water is required. Glass beads coated with bismuth oxide were incubated with either Microcystis aeruginosa, Anabaena sp. or free-floating genomic DNA. The presence of bismuth oxide-coated glass beads was able to rapidly stop a population of cyanobacteria from increasing. The coated beads were also able to degrade genomic DNA. Leachate from the beads showed no increase in toxicity against human liver cells. This data demonstrates the efficacy of bismuth oxide-coated glass beads for controlling potentially dangerous cyanobacterial populations, whilst potentially reducing the amount of free-floating genomic DNA(an essential issue in the face of antimicrobial resistance) – all of which should be essential considerations in emerging water treatment technologies.

Novel environmentally friendly inorganic red pigments based on calcium bismuth oxides

Novel environmentally friendly inorganic red pigments based on calcium bismuth oxide Ca3(Bi1-xREx)8O15(0≤x≤0.09;RE=Sc^(3+),Er^(3+),Y^(3+),Ho^(3+)and Dy^(3+)),were successfully synthesized and the color properties were characterized.The color of these pigments depended on the composition and the synthesis condition,and the most vivid red color was obtained for the Ca3(Bi0.93Y0.07)8O15 sample calcined thrice at 800℃for 2 h.The L*and a*values corresponding to brightness and red chromaticity for this pigment were 45.6 and+30.6,respectively,which were greater than those of a commercially available Fe2O3 pigment(L^(*)=38.4,a^(*)=+29.5).Since the present pigment is composed of nontoxic and safe elements,it should be an attractive alternative to the conventional Fe2O3 pigment.

Research Progress on the Bismuth Containing Complex Oxide in Photocatalystic Technology

The photocatalytic degradation on the bismuth containing complex oxide was revised in detail including the synthesis and classification of photocatalyts, and then the photocatalytic reaction, scavenger, and the mechanism of reaction. In particular, the perspectives of photocatalytic degradation on the bismuth containing oxide were analyzed in detail.

Composite Cathode Bi_(1.14)Sr_(0.43)O_(2.14)-Ag for Intermediate-temperature Solid Oxide Fuel Cells

Composites consisting of strontium stabilized bismuth oxide （Bi1.14Sr0.43O2.14, SSB） and silver were investigated as cathodes for intermediate-temperature solid oxide fuel cells with doped ceria electrolyte. There were no chemical reactions between the two components. The microstructure of the interfaces between composite cathodes and Ce0.8Sm0.2O1.9 （SDC） electrolytes was examined by scanning electron microscopy （SEM）. Impedance spectroscopy measurements show that the performance of cathode fired at 700 ℃ is the best. When the content of Ag2O is 70 wt%, polarization resistance values for the SSB-Ag cathodes are as low as 0.2 Ωcm^2 at 700℃ and 0.29 Ωcm^2 at 650℃. These results are much smaller than some of other reported composite cathodes on doped ceria electrolyte and indicate that SSB-Ag composite is a potential cathode material for intermediate temperature SOFCs.

Metal-organic-frameworks passivated CuBi_(2)O_(4)photocathodes boost CO_(2)reduction kinetics

Photoelectrochemical reduction of CO_(2)to produce CO with metal-organic frameworks(MOFs)is recognized as a desirable technology to mitigate CO_(2)emission and generate sustainable energy.To achieve highly efficient electrocatalyst,it is essential to design a new material interface and uncover new reaction mechanisms or kinetics.Herein,we developed two metal-organic Cu-MOF and Bi-MOF layers using benzene tricarboxylic acid(H_(3)BTC)ligands on CuBi_(2)O_(4) photocathodes.Both MOF layers drastically improved the photoelectrochemical stability by suppressing the photo-corrosion through conformal surface passivation.The Cu-MOF modified CuBi_(2)O_(4) showed more significant charge separation and transfer efficiencies than the Bi-MOF modified control.Based on the transient photocurrent curves under the applied potential of 0.6 V vs.RHE,the rate-law analysis showed the CO_(2)photoreduction took place through a first-order reaction.Further,the photoelectrochemical impedance spectra(PEIS)revealed this reaction order,representing an“operando”analysis.Moreover,the reaction rate constant on Cu-MOF modified sample was higher than that on Bi-MOF modified one and bare CuBi_(2)O_(4).Combined with the density functional theory calculation,the surface absorption of CO_(2)and CO molecules and the higher energy barrier for*COOH intermediates could significantly determine the first order reaction.

A Decisive Study on Dielectric Response of Bi2O3/Polystyrene &Bi2O3/PVDF Composite as Flexible Electrodes for Energy Storage

In this manuscript a comparative study on Bi2O3/polystyrene and Bi2O3/PVDF composites has been executed via analysis of structural, bonding, surface morphology and dielectric response of composites for energy storage. The composites have been synthesized using solution cast method by varying concentrations of Bi2O3 (BO = 1 - 5 mw%) into polystyrene (PS) and polyvinylidene fluoride (PVDF) polymers respectively. X-ray diffraction confirms the generation of crystallinity, Fourier transform infrared (FT-IR) spectroscopy confirms bonding behavior and scanning electron microscopy (SEM) confirms uniform distribution of Bi2O3 (BO) in PS and PVDF polymers. Impedance spectroscopy has been employed for determination of dielectric response of the fabricated composites. The dielectric constant has been found to be increased as 1.4 times of pristine PS to BO5%PS95% composites and 1.8 times of pristine PVDF to BO5%PVDF95% composites respectively. These high dielectric composite electrodes are useful for flexible energy storage devices.

High-capacity Bi_(2)O_(3) anode for 2.4 V neutral aqueous sodium-ion battery-supercapacitor hybrid device through phase conversion mechanism

Aqueous battery-supercapacitor hybrid devices(BSHs)are of great importance to enrich electrochemical energy storage systems with both high energy and power densities.However,further improvement of BSHs in aqueous electrolytes is greatly hampered by operating voltage and capacity limits.Different from the conventional intercalation/de-intercalation mechanism,Bi_(2)O_(3) implements charge storage by a reversible phase conversion mechanism.Herein,taking Bi_(2)O_(3) electrode with wide potential window(from-1.2 to 1 V vs.saturated calomel electrode)and high capacity as battery-type anode,we propose that the overall performance of aqueous BSHs can be greatly upgraded under neutral condition.By paring with stable layer-structuredδ-MnO_(2) cathode,a sodium-ion Bi_(2)O_(3)//MnO_(2) BSH with an ultrahigh voltage of 2.4 V in neutral sodium sulfate electrolyte is developed for the first time.This hybrid device exhibits high capacity(~215 C g^(-1) at 1 mA cm^(-2)),relatively long lifespan(~77.2%capacity retention after 1500 cycles),remarkable energy density(71.7 Wh kg^(-1)@400.5 W kg^(-1))and power density(3204.3 W kg^(-1)@18.8 Wh kg^(-1)).Electrochemical measurements combining a set of spectroscopic techniques reveal the reversible phase conversion between bismuth oxide and metallic bismuth(Bi_(2)O_(3)?Bi0)through Bi^(2+) transition phase in neutral sodium sulfate solution,which can deliver multielectron transfer up to 6,leading to the high-energy BSHs.Our work sheds light on the feasibility of using Bi_(2)O_(3) electrode under neutral condition to address the issue of narrow voltage and low capacity for aqueous BSHs.

Point-defect engineering of nanoporous CuBi_(2)O_(4) photocathode via rapid thermal processing for enhanced photoelectrochemical activity

Engineering point defects such as metal and oxygen vacancies play a crucial role in manipulating the electrical,optical,and catalytic properties of oxide semiconductors for solar water splitting.Herein,we synthesized nanoporous CuBi_(2)O_(4)(np-CBO)photocathodes and engineered their surface point defects via rapid thermal processing(RTP)in controlled atmospheres(O_(2),N_(2),and vacuum).We found that the O_(2)-RTP treatment of np-CBO increased the charge carrier density effectively without hampering the nanoporous morphology,which was attributed to the formation of copper vacancies(VCu).Further analyses revealed that the amounts of oxygen vacancies(Vo)and Cu^(1+)were reduced simultaneously,and the relative electrochemical active surface area increased after the O_(2)-RTP treatment.Notably,the point defects(VC_(u),Cu^(1+),and Vo)regulated np-CBO achieved a superb water-splitting photocurrent density of-1.81 m A cm^(-2) under simulated sunlight illumination,which is attributed to the enhanced charge transport and transfer properties resulting from the regulated surface point defects.Finally,the reversibility of the formation of the point defects was checked by sequential RTP treatments(O_(2)-N_(2)-O_(2)-N_(2)),demonstrating the strong dependence of photocurrent response on the RTP cycles.Conclusively,the surface point defect engineering via RTP treatment in a controlled atmosphere is a rapid and facile strategy to promote charge transport and transfer properties of photoelectrodes for efficient solar water-splitting.

Nonlinear Optical Properties in Bi_2O_3-B_2O_3-SiO_2 Glasses

A series of bismuth borate silica glasses were prepared and their densities, linear refractive indices and transmission spectra were measured. The optical gaps Eopt were obtained from the extrapolation of the linear portions to zero absorption. A decrease in the value of Eopt with increasing bismuth content may be explained by suggesting that the non-bridging oxygen ion content increases .It was found that high refractive index and narrow bandgap could lead into high third-order optical nonlinearity.

Pressureless reactive sintering mechanism of nanocrystalline Bi_2O_3-Y_2O_3 solid electrolyte

The nanocrystalline Bi2O3-Y2O3 solid electrolyte material was synthesized by pressureless reactive sintering process with Bi2O3 and Y2O3 nano mixed powder as raw materials, which was prepared by a chemical coprecipitation process. The study on the behavior of nano δ-Bi2O3 formation and its grain growth showed that the solid solution reaction of Y2O3 and δ-Bi2O3 to form δ-Bi2O3 occurs mainly in the initial stage of sintering process, and nano δ-Bi2O3 crystal grains grow approximately following the rule of paracurve （（D-D0）^2=K.t） during sintering process. After sintered at 600℃ for 2 h, the samples could reach above 96% in relative density and have dense microstructure with few remaining pores, the δ-Bi2O3 grains are less than 100 nm in size.

Syntheses，Structures and Properties of Some New Composition Perovskite Compounds：Sr0．6Bi0．4FeO2．7，Sr1－xBixFeO3－y and Ba1．5Pt0．5Mn2O6

New composition perovskite-type compounds with formula Sr0.6Bi0.4FeO2.7,Sr1-xBixFeO3-y(x=0.1 to 0. 9 in interveral of 0.1),and Ba1.5Pt0.5Mn2O6 have been synthsized and structurally characterized.The crystal structure of Sr0.6Bi0.4FeO2.7has been determined by X-ray single crystal diffraction,and the data of neutron powder diffraction collected at both room temperature and elevated temperature(380℃).The compound Sr0.6Bi0.4FeO2.7 crystallizes in the cubic space group of Pm3m with Z=1,a=3.9330(6) at room temperature,a=3.9498(6)A at 380℃.The magnetic structure from the neutron powder diffraction data collected at room temperature is consistent with a simple G-type antiferromagnetism and has a magnetic moment of 4.98 μB per Fe atom.The structures of Sr1-xBixFeO3-y with x other than 0.4 were also refined from the X-ray powder diffraction data.The data were consistent with a tetragonal cell when x=0.1,a rhombohedral cell when x= 0.9,and a cubic cell for x=0.2～0.8.From single crystal X-ray diffraction data,Ba1.5Pt0.5Mn2O6 crystallizes in hexagonal space group of P63mc with a= 5.7722 (6),c=4.4504(9),V=128.42(2),Z=1.The Sr(1-x)BixFeO(3-y)are found to be a good electronic and ionic conductor.

Reduced graphene oxide decorated with Bi2O2.33 nanodots for superior lithium storage

Bismuth oxides are important battery materials owing to their ability to electrochemically react and alloy with Li,which results in a high capacity level,which substantially exceeds that of graphite anodes.However,this high Li-storage capability is often compromised by the poor electrochemical cyclability and rate capability of bismuth oxides.To address these challenges,in this study,we design a hybrid architecture composed of reduced graphene oxide （rGO） nanosheets decorated with ultrafine Bi2O2.33 nanodots （denoted as Bi2O2.33/rGO）,based on the selective and controlled hydrolysis of a Bi precursor on graphene oxide and subsequent crystallization via solvothermal treatment.Because of its high conductivity,large accessible area,and inherent flexibility,the Bi2O2.33/rGO hybrid exhibits stable and robust Li storage （346 mA＆#183;h＆#183;g-1 over 600 cycles at 10 C）,significantly outperforming previously reported Bi-based materials.This superb performance indicates that decorating rGO nanosheets with ultrafine nanodots may introduce new possibilities for the development of stable and robust metal-oxide electrodes.

Construction of charge transfer chain in Bi_(12)TiO_(20)-Bi_(4)Ti_(3)O_(12)/α-Bi_(2)O_(3)composites to accelerate photogenerated charge separation

Photogenerated charge separation and transfer is one of the bottleneck steps in photocatalysis,and efficient charge separation strategies are strongly desired.Here,mimicking the electron transport chain in natural photosynthesis,we report the design and fabrication of a charge transfer chain using bismuth-based semiconductor as a proof-of-concept.In view of the thermodynamic energy band positions and structural similarity based on the density functional theory(DFT)analysis,heterostructured combination ofα-Bi_(2)O_(3),perovskite-like Bi_(4)Ti_(3)O_(12),and sillenite Bi12TiO20 was designed for fabrication of charge transfer chain.By tuning the molar ratio of Bi and Ti precursors,the Bi_(4)Ti_(3)O_(12)and Bi12TiO20 particles were formed on the surface ofα-Bi_(2)O_(3)by an insitu transformation process,giving rise to Bi_(12)TiO_(20)-Bi_(4)Ti_(3)O_(12)/α-Bi_(2)O_(3)composites with charge transfer chain.We propose that the effective charge transfer is accomplished amongα-Bi_(2)O_(3),Bi12TiO20,and Bi_(4)Ti_(3)O_(12),which significantly improves the photogenerated charge separation and transfer,as indicated by photoluminescene,time-resolved photoluminescene,and electrochemical impedance spectra results.As expected,the Bi_(12)TiO_(20)-Bi_(4)Ti_(3)O_(12)/α-Bi_(2)O_(3)shows the superior photocatalytic activity for the degradation of environmental pollutants with high concentration.Even for the refractory pollutants like 4-chlorophenol,the optimal Bi_(12)TiO_(20)-Bi_(4)Ti_(3)O_(12)/α-Bi_(2)O_(3)composite shows 28 times higher than that ofα-Bi_(2)O_(3)for photocatalytic degradation,verifying the superiority of photogenerated charge transfer chain in photocatalysis.This work demonstrates the feasibility of the charge transfer chain strategy to boost the photogenerated charge separation,which is of great significance for designing energy and environmental-related materials in heterogonous photocatalysis.

Enhanced catalytic oxidation of 2,4-dichlorophenol via singlet oxygen dominated peroxymonosulfate activation on CoOOH@Bi_(2)O_(3)composite

Cobalt oxyhydroxide(CoOOH)has been turned out to be a high-efficiency catalyst for peroxymonosulfate(PMS)activation.In this study,CoOOH was loaded on bismuth oxide(Bi_(2)O_(3))using a facile chemical precipitation process to improve its catalytic activity and stability.The result showed that the catalytic performance on the 2,4-dichlorophenol(2,4-DCP)degradation was significantly enhanced with only 11 wt%Bi_(2)O_(3)loading.The degradation rate in the CoOOH@Bi_(2)O_(3)/PMS system(0.2011 min−1)was nearly 6.0 times higher than that in the CoOOH/PMS system(0.0337 min−1).Furthermore,CoOOH@Bi_(2)O_(3)displayed better stability with less Co ions leaching(16.4%lower than CoOOH)in the PMS system.These phenomena were attributed to the Bi_(2)O_(3)loading which significantly increased the conductivity and specific surface area of the CoOOH@Bi_(2)O_(3)composite.Faster electron transfer facilitated the redox reaction of Co(III)/Co(II)and thus was more favorable for reactive oxygen species(ROS)generation.Meanwhile,larger specific surface area furnished more active sites for PMS activation.More importantly,there were both non-radical(^(1)O_(2))and radicals(SO_(4)^(−)•,O_(2)^(−)•,and OH•)in the CoOOH@Bi_(2)O_(3)/PMS system and^(1)O_(2)was the dominant one.In general,this study provided a simple and practical strategy to enhance the catalytic activity and stability of cobalt oxyhydroxide in the PMS system.

Solvothermal synthesis of Bi_2O_3/BiVO_4 heterojunction with enhanced visible-light photocatalytic performances

Novel, three-dimensional, flower-like Bi203/BiVO4 heterojunction photocatalysts have been prepared by the combination of homogeneous precipitation and two-step solvothermal method followed by thermal solu- tion of NaOH etching process. The as-obtained samples were fully characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Brunauer-Emmett-Teller surface area, and UV-vis diffuse- reflectance spectroscopy in detail. The crystallinity, microstructure, specific surface area, optical property and photocatalytic activity of samples greatly changed depending on solvothermal reaction time. The photocatalytic activities of samples were evaluated on the degradation of methyl orange （MO） under visible-light irradiation. The Bi203/BiVO4 exhibited much higher photocatalytic activities than pure BiVO4 and conventional TiO2 （P25）. The result revealed that the three-dimensional heterojunction played a critical role in the separation of the electron and hole pairs and enhancement of the interfacial charge transfer efficiency, which was responsible for the enhanced photocatalytic activity.

Facile autoreduction synthesis of core-shell Bi-Bi2O3/CNT with 3-dimensional neural network structure for high-rate performance supercapacitor

Core-shell Bi-Bi2 O3/CNT(carbon nanotube) with 3-dimensional neural network structure where Bi-Bi2O3 nanospheres act as cell bodies supported by a 3-dimensional network of CNTs acting as synapses is designed and prepared by simple solvothermal method and subsequent annealing autoreduction treatment,and this structure facilitates the efficient transport of electrons.It can provide two electron transfer paths due to the double contact of Bi2O3 shell with CNT and metal Bi core which enhances the efficiency of the electrochemical reaction.The Bi-Bi2 O3/CNT electrode shows a high gravimetric capacitance of 850 F g-1(1 A g-1),and the specific capacitance of Bi-Bi2O3/CNT can be still 714 F g-1 at 30 A g-1 indicating excellent rate performance.The asymmetric supercapacitor is assembled with Bi-Bi2 O3/CNT as the negative electrode and Ni(OH)2/CNT as the positive electrode,delivering a high energy density of 36.7 Wh kg-1 and a maximum power density of 8000 W kg-1.Therefore,the core-shell Bi-Bi2O3/CNT with 3-dimensional neural network structure as the negative electrode of supercapacitor shows great potential in the field of energy storage in the future.