Addition Of Bismuth Research Articles

Evropeyskiy registr Helicobacter pylori (Hp-EuReg): analiz dannykh 2360 bol'nykh, poluchavshikh terapiyu pervoy linii v Rossii

European Registry on the management of Helicobacter pylori infection («Hp-EuReg») - a multicenter prospective observational study initiated by the European Helicobacter and Microbiota Study Group, conducted in 27 European countries in order to evaluate the real clinical practice of diagnosis and treatment of H. pylori and its comparison with international recommendations. The analysis of 2360 patients entered in the register by the Russian centres of «Hp-EuReg» in 2013-2017, who were underwent 1st line eradication therapy. The most common methods of primary diagnosis of H. pylori are histological (37.7%), rapid urease test (29.2%) and serology (29.7%). The duration of eradication therapy in 9.4% of cases was 7 days, in 65.3% - 10 days, and in 25.3% - 14 days. To control the effec- tiveness of treatment, H. pylori antigen in feces (31.3%), urea breath test (23.4%) and histological method (23.3%) were used. In 3.6% cases was used serology by mistake. In 17.3% of patients control was not carried out. The effectiveness of triple therapy with a PPI, amoxicillin, clar- ithromycin (per protocol) was 67.6%, with 7-day course, 81.1% at 10-day and 86.7% at 14-day course. Eradication rate of triple therapy with addition of bismuth (per protocol) reached 90,6% in the group receiving 10-day scheme and 93.6% in the group receiving the 14-day treatment. Significant deviations of clinical practice from expert recommendations, most pronounced at the stage of monitoring the effectiveness of therapy, were noted. The suboptimal efficacy of triple therapy is shown.

Role of Bismuth in the Electrokinetics of Silicon Photocathodes for Solar Rechargeable Vanadium Redox Flow Batteries.

The ability of crystalline silicon to photoassist the V3+ /V2+ cathodic reaction under simulated solar irradiation, combined with the effect of bismuth have led to important electrochemical improvements. Besides the photovoltage supplied by the photovoltaics, additional decrease in the onset potentials, high reversibility of the V3+ /V2+ redox pair, and improvement in the electrokinetics were attained thanks to the addition of bismuth. In fact, Bi0 deposition has shown to slightly decrease the photocurrent, but the significant enhancement in the charge transfer, reflected in the overall electrochemical performance clearly justifies its use as additive in a photoassisted system for maximizing the efficiency of solar charge to battery.

Improved microstructure and sintering temperature of bismuth nano-doped GDC powders synthesized by direct sol-gel combustion

To improve the microstructural and electrochemical properties of Gadolinium-doped ceria (GDC) electrolytes, materials co-doped ceria with bismuth oxide (1–5mol%) have been successfully prepared in a one-step sol-gel combustion synthetic route. Sol-gel combustion facilitates molecular mixing of the precursors and substitution of the large Bi3+ cations into the fluorite structure, considerably reducing the sintering temperature. Adding Bi2O3 as a dopant increases the GDC densification to above 99.7% and reduces its traditional sintering temperature by 300°C. Impedance analyses show that the addition of bismuth enhances the conductivity (3.1∙10−2−1.7∙10−1S·cm−1 in the temperature range 600–800°C) and improves the performance of the solid electrolyte in intermediate-temperature solid oxide fuel cells.

Use of electron microprobe analysis to explain metallurgical phenomena and their effect on properties when welding stainless steel

A modified electron probe microanalysis (EPMA) instrument containing six wavelength dispersive spectrometers has been used for mapping cross-sections of stainless steel base material and welds. It made it possible to measure the composition in specific small areas and to illustrate element partitioning; ranging from centerline segregation to concealed sub-microstructure. Examples from industrial research are given to demonstrate the versatile application field for this established technology. EPMA was used to study the chemical composition of gas tungsten arc welds in the lean duplex grade UNS S32101 performed with and without nitrogen additions to the argon-based shielding gas. The level of nitrogen in the shielding gas not only determined the weld metal nitrogen content, but also affected evaporation of other elements from the weld metal. Mapping could also be used to reveal detailed information about the dendritic substructure in welds and the fusion line that could not be seen with conventional microscopy as the weld metal microstructure is controlled by nitrogen. With the measured local composition, it was possible to calculate the pitting resistance equivalent number, PRE = Cr + 3.3 × Mo + 16 × N (wt%) and thereby visualize the local variation in the microstructure. Nitrogen is strongly concentrated in the austenite and has the largest impact on the PRE. Pitting corrosion testing confirmed that the ferrite phase was most susceptible to pitting attack and that a higher average PRE does not significantly increase the critical pitting temperature. The EPMA instrument was also applied to study all-weld metal of E347T0 type flux-cored wire with and without bismuth additions. Bismuth can have a negative effect on weld metal ductility after post-weld heat treatment and/or applications at high temperature. It has been suggested that this is due to grain boundary bismuth segregation, and it has been debated whether it occurs as bismuth or bismuth oxide Bi2O3. Hot tensile testing confirmed that the bismuth content affects the weld metal ductility at 700 °C and EPMA proved that bismuth segregates as round particles after post-weld heat treatment and not as bismuth oxide.

Improving the standard sequential treatment of Helicobacter pylori with either extended treatment or by adding bismuth

Background and study aimsStandard sequential treatment for Helicobacter pylori (H. pylori) eradication has less success because of increasing clarithromycin resistance. Extended treatment and bismuth containing regimens were, therefore, investigated. Patients and methodsConsecutive H. pylori-positive patients with dyspepsia were randomly allocated to one of the three sequential regimens: The first group was given lansoprazole 30mg b.i.d. plus amoxicillin 1g b.i.d. for the first 5days, followed by lansoprazole 30mg b.i.d., clarithromycin 500mg b.i.d., and metronidazole 500mg t.i.d. for the second 5days (standard sequential, SS). The second group was given the same regimen but for 7+7days instead of 5+5days (extended sequential, ES). In the third group, colloidal bismuth 600mg b.i.d. was added to the second regimen for 14days (extended sequential+bismuth subcitrate, ES+B). Urea breath test or histology was performed before enrolment and 6weeks after the end of treatment to detect H. pylori. ResultsA total of 280 patients were included in the study. Per-protocol eradication rates were 62% (56/90), 72% (56/78), and 75% (54/72) in patients who received SS, ES, and ES+B regimens, respectively. Moreover, intention-to-treat eradication rates were 53% (56/104), 62% (56/90) and 62% (54/86), respectively. The differences in eradication rates between the groups were not statistically significant. ConclusionAlthough prolonging of the sequential treatment to 14days may be considered, addition of bismuth to the regimen is of no avail.

The diagnosis and management of H. pylori infection in Singapore.

Helicobacter pylori (H. pylori) is an infection that has a role in causing dyspepsia and complications such as peptic ulcer disease and gastric malignancies. In the primary care setting, one can adopt a stepwise approach with the 'test-and-treat' strategy to manage H. pylori-associated dyspepsia in young patients without alarm symptoms. Empiric first-line therapies should be for a two-week duration; options include clarithromycin-containing triple therapy alone or with the addition of bismuth, concomitant therapy and bismuth quadruple therapy. Post-treatment carbon urea breath test must be performed at least four weeks after the end of treatment to confirm the cure. Options for empiric second-line treatment include bismuth quadruple therapy and levofloxacin-containing triple therapy. Patients with persistent or alarm symptoms should be referred for further evaluation. Patients with persistent infection should be referred for gastroscopy so that gastric biopsies can be obtained for H. pylori culture and antibiotic susceptibility testing.

Ageing and Degradation Effects Observed in Carbon Felts Used As Electrodes in Vanadium Redox Flow Batteries

With dwindling fossil resources and growing environmental concerns, clean and efficient energy conversion and storage technologies are getting more and more attention from the public. Lithium ion batteries, redox flow batteries as well as fuel cells hold the promise and burden to sustain our energy-demanding society. In recent years, several efforts have been addressed to vanadium redox flow batteries (VRFB) which show great promise for the economical storage of electrical energy intermittently available from wind and solar. The excess energy is stored in liquid electrolytes using the four oxidation states of Vanadium, V2+/3+ at the negative, V4+/5+at the positive side. The liquid electrolytes flow through porous carbon felt electrodes, which provide a heterogeneous reaction surface. The main reasons to use carbon felts are their corrosion resistance in acidic electrolyte, high overpotential towards the unwanted hydrogen evolution reaction (HER) and low material costs. In addition, their activity towards the positive and negative reaction, respectively, can be modified using thermal oxidation in air atmosphere, acid treatment, heteroatom doping, and others. With respect to stationary applications with projected system runtimes of 10˙000 hours and more, not only activity, but also durability of the electrode materials moves into the focus of current research. It has been reported [1] that the carbon felts undergo significant degradation when cycled for a certain number of times. However, already the electro-less contact with the highly acidic electrolytes seems to affect the felts properties. In this study, static electro-less ageing and dynamic degradation of heat-treated carbon felt electrodes were investigated by combining different electrochemical and analytical methods. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to monitor the performance loss of the carbon-based electrodes, whereas scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were applied to study cause and effects of material’s degradation. In this respect, oxygen functional groups, electron conductivity, wettability, accessible surface area and other characteristics play an important role. In general, the HER is a parasitic reaction, which should be hindered in favor of the V3+ reduction. It has been reported that bismuth additions to the electrolyte enhance the activity of the felt for the negative reaction without enhancing the HER [2]. However, the competition between HER and V3+reduction can also be used as an indicator of the felt’s state of health when probed at different temperatures and in different electrolyte concentrations. We will discuss this for differently degraded felts. Furthermore, we use our battery tester with implemented reference electrodes to compare the individual half-cell potentials with full cell potentials and to study the effect of different cut-off voltages on the projected electrode degradation. Higher cut-off potentials might prove effective for the system’s operation strategy, if they do not lead to the expected increased degradation phenomena. [1] I. Derr, M. Bruns, J. Langner, A. Fetyan, J. Melke, C. Roth „Degradation of all-vanadium redox flow batteries (VRFB) investigated by electrochemical impedance and X-ray photoelectron spectroscopy: Part 2 electrochemical degradation, Journal of Power Sources 325 (2016) 351-359. [2] B. Li, M. Gu, Z. Nie, Y. Shao, Q. Luo, X. Wei, X. Li, J. Xiao, C. Wang, V. Sprenkle, W. Wang Nano Letters. 13 (2013) 1330-1335.

Microstructure, In Vitro Corrosion Behavior and Cytotoxicity of Biodegradable Mg-Ca-Zn and Mg-Ca-Zn-Bi Alloys

The effects of bismuth (Bi) addition on the microstructure and corrosion behavior of the Mg-Ca-Zn-Bi alloys were evaluated using electron microscopy, electrochemical test and electrochemical impedance spectroscopy. Microstructural observations showed that Mg-1.2Ca-1Zn-xBi (x = 0.5, 1.5, 3 wt.%) are composed of Mg2Ca, Ca2Mg6Zn3 and Mg3Bi2 phases while a new phase Mg2Bi2Ca appeared after the addition of 5 and 12 wt.% Bi to the Mg-1.2Ca-1Zn alloy. Furthermore, the additions of 0.5 wt.% Bi to the Mg-1.2Ca-1Zn alloy slightly improved the corrosion behavior of the alloy, while further increase in Bi amount from 1.5 to 12 wt.% has a deleterious effect on the corrosion behavior of the ternary Mg-1.2Ca-1Zn alloy which is driven by galvanic coupling effect. Cytotoxicity tests indicate that the Mg-1.2Ca-1Zn presents higher cell viability compared to Mg-1.2Ca-1Zn-0.5Bi alloy. In addition, the cell viability of both alloys increased with increasing incubation time while diluting the extracts to 50% and 10% improved the cell viabilities. The present results suggest that the Mg-1.2Ca-1Zn-0.5Bi can be interesting candidate for the development of degradable biomaterials and it is worthwhile for further investigation in an in vivo environment.

Influence of bismuth on the solidification of Sn-0.7Cu-0.05Ni-xBi/Cu joints

The improvement of solder joint mechanical performance due to bismuth additions is of ongoing interest. This paper investigates the influence of 0–14 wt% Bi on microstructure formation in Sn-0.7 wt%Cu-0.05 wt%Ni-xBi solder balls on Cu substrates. It is shown that Bi additions reduce the Ni content of (Cu,Ni)6Sn5, increase the size of primary (Cu,Ni)6Sn5 rods and reduce the thickness of the Cu6Sn5 reaction layer, although these effects are subtle until the Bi content reaches ∼5 wt%Bi and Bi additions of ≤5 wt% did not significantly affect the positive effects of Ni. Higher Bi additions (≥8 wt% Bi) caused a transition of the tin growth texture from columnar grains with a <110> fibre texture towards a single grain with subgrains. Bi additions increased the non-equilibrium freezing range and caused a nonequilibrium ternary eutectic reaction in joints containing ≥2 wt% Bi. Bi contents less than 2 wt% are required to prevent (Bi) phase formation during solidification.

Theoretical prediction of thermodynamic activities of liquid Au-Sn-X (X=Bi, Sb, Zn) solder systems

Molecular interaction volume model has been theoretically used to predict the thermodynamic activities of tin in Au-Sn-Bi and Au-Sn-Sb and the thermodynamic activity of zinc in Au-Sn-Zn at experimental temperatures 800K, 873K and 973K, respectively. On the premise of agreement between the predicted and experimental values, we predicted the activities of the remaining two components in each of the three systems. This prediction was extended from three cross-sections to five cross-sections, and to temperature range 400–600K, relevant for applications. Iso-activities were plotted. Results show that addition of tin reduces the tendency for chemical short range order in both Au-Sb and Au-Zn systems, while addition of gold and bismuth, respectively, reduce the tendency for chemical short range order in Sn-Sb and Au-Sn systems. Also, we found that, in the desired high-temperature region for applications, while a combination of chemical order and miscibility of components exist in both Au-Sn-Bi and Au-Sn-Zn systems, only chemical order exist in the Au-Sn-Sb system. Results, further show that increase in temperature reduces the phase separation tendency in Au-Sn-Bi system.

EXTREME PRESSURE SYNERGISTIC MECHANISM OF BISMUTH NAPHTHENATE AND SULFURIZED ISOBUTENE ADDITIVES

A four-ball tester was used to evaluate the tribological performances of bismuth naphthenate (BiNap), sulfurized isobutene (VSB), and their combinations. The results show that the antiwear properties of BiNap and VSB are not very visible, but they possess good extreme pressure (EP) properties, particularly sulfur containing bismuth additives. Synergistic EP properties of BiNap with various sulfur-containing additives were investigated. The results indicate that BiNap exhibits good EP synergism with sulfur-containing additives. The surface analytical tools, such as X-ray photoelectron spectrometer (XPS) scanning electron microscope (SEM) and energy dispersive X-ray (EDX), were used to investigate the topography, composition contents, and depth profile of some typical elements on the rubbing surface. Smooth topography of wear scar further confirms that the additive showed good EP capacities, and XPS and EDX analyzes indicate that tribochemical mixed protective films composed of bismuth, bismuth oxides, sulfides, and sulfates are formed on the rubbing surface, which improves the tribological properties of lubricants. In particular, a large number of bismuth atoms and bismuth sulfides play an important role in improving the EP properties of oils.

Polycrystalline Bi substituted YIG ferrite processed via low temperature sintering

Polycrystalline Bi substituted YIG ferrite (i.e., Y3-xBixFe5O12) has been widely studied due to its high electrical resistivity, moderate to high magnetization and permeability, and relatively low processing cost. Furthermore, it is suitable for large-scale industrial production making it a viable material for mass-produced filters, inductors, isolators, and other rf components. However, low temperature co-fired ceramic technology requires sintering temperatures below ∼960 °C (i.e., the approximate melting point of the silver electrodes are ∼961 °C) while maintaining a low ferromagnetic resonance linewidth (ΔH) and other desirable properties. This work reports the effect of bismuth addition on the ferromagnetic properties of low-temperature sintered Y3-xBixFe5O12 (x = 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2) garnet ferrites. The microstructure, magnetic properties, and gyromagnetic properties of the Bi-YIG samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and ferromagnetic resonance (FMR). Results support the processing of pure phase garnet, with moderate values of saturation magnetization and FMR linewidth for x = 0.9. Moreover, the Fano algorithm was shown to provide superior fitting to asymmetric FMR spectra allowing for very accurate measurement of ΔH.

Corrosion Behavior of Sn-1Ag-0.5Cu Solder Alloy with the Addition of Fe and Bi

The needs for lead free solders have risen over concerns about the toxicity of Pb particularly to the public health and the environment. In line with current technological developments, the use of electronics has expanded to various applications such as industrial and automotive applications. This demands a higher reliability and durability of the device in more challenging operating environments that includes corrosive medium and moisture. In this work, we prepared Sn-1Ag-0.5Cu (SAC105) lead-free solder alloys with the addition of iron (Fe) and bismuth (Bi) and extensively investigated their corrosion behavior and microstructures. To characterize the corrosion behavior, combinations of physical (weight loss) and electrochemical tests (potentiodynamic polarization and impedance spectroscopy) were carried out in 0.1M NaCl solution, for various periods of time. In order to mechanistically understand the corrosion behavior of the solder alloys, an understanding of the microstructure is important as the alloying elements dictate the type of microstructure that is present within an alloy. The microstructural characterization and damage accumulation were executed by means of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The correlation between electrochemical measurements and microstructural characterizations were made to clarify and quantify the overall performance of the SAC105 with addition of Fe and Bi.

Creep Characteristic of Sn1.0Ag0.7Cu Lead-Free Solders with Element Addition

In this study, creep properties of lead-free solders based on Sn1.0Ag0.7Cu were investigated. In the solders, germanium, nickel and bismuth were added to improve their mechanical properties. The effect of element addition on their microstructure and creep properties were studied. Creep properties were improved with the element addition. Creep rupture lifetime was the longest for SnAgCuBiNiGe, and that of SnAgCuBi was the second longest. It was made clear that a minimum creep strain rate is useful for lifetime prediction of the solders. An observation of microstructure was performed and coarsening of intermetallics after creep test was identified, resulting in creep rupture. It was found that the addition of bismuth hinders the coarsening of intermetallics and is effective to improve the creep properties of the solders.

High-Temperature Dielectrics in BNT-BT-Based Solid Solution.

Bi0.5Na0.5TiO3-BaTiO3 (BNT-BT)-based ternary solid solutions were investigated for high-temperature capacitor applications. Through a comprehensive investigation of the (1 - x )(0.92Bi0.5Na0.5TiO3-0.08BaTiO3)- x NaNbO3 [(1 - x )(BNT-BT)- x NN, x = 0 -0.45] system, 0.85(BNT-BT)-0.15NN was selected as the parent matrix due to its relatively high permittivity (>1800) and favorable energy-storage density (0.56 J/cm3 at 7 kV/mm). The effect of bismuth substitution on the dielectric properties of the matrix was further characterized. The introduction of bismuth greatly broadened the operational temperature range of 0.85(BNT-BT)-0.15Na1-3yBiyNbO3 ceramics to over 327 °C for a ±15% tolerance. The dc resistivities were of the order of 108 - [Formula: see text] magnitude from room temperature to 300 °C. An activation energy of 1.1-1.2 eV in 200-350 °C was obtained from dc resistivity data, suggesting that the conduction process in this temperature range may be associated with oxygen vacancy migration. Furthermore, the energy-storage properties were largely improved by the addition of bismuth. When the substitution of Bi over Na achieved was up to 7%, the energy-storage density and efficiency reached 0.62 J/cm3 and 88% at 7 kV/mm, respectively. These results confirm that a BNT-BT-based solid solution is a promising candidate for lead-free high-temperature capacitor applications.

Eradication of Helicobacter pylori Infection.

Helicobacter pylori infects about 50% of the world's population, causing at a minimum chronic gastritis. A subset of infected patients will ultimately develop gastric or duodenal ulcer disease, gastric adenocarcinoma, or MALT (mucosa-associated lymphoid tissue) lymphoma. Eradication of H. pylori requires complex regimens that include acid suppression and multiple antibiotics. The efficacy of treatment using what were once considered standard regimens have declined in recent years, mainly due to widespread development of antibiotic resistance. Addition of bismuth to standard triple therapy regimens, use of alternate antibiotics, or development of alternative regimens using known therapies in novel combinations have improved treatment efficacy in specific populations, but overall success of eradication remains less than ideal. Novel regimens under investigation either in vivo or in vitro, involving increased acid suppression ideally with fewer antibiotics or development of non-antibiotic treatment targets, show promise for future therapy.

Mechanical Properties of Parts with Tin Coating Obtained by Hot-Dip Method

Hot-dip process leading to creation of protective coating is one of the effective ways to protect metals from corrosion. It provides the way to obtain the coating with required physical, mechanical and chemical properties. However, contact of solid metal part with the liquid metal bath during this process may lead to changes in mechanical properties or, in extreme cases, to premature failure of the part. This is mainly due to the effect called LME. The author has researched the likelihood of occurrence of this phenomenon in parts subjected to metallization in zinc bath or in zinc bath with additions of tin or bismuth. The presented results are a continuation of these research and include an assessment of the possibility of LME occurrence in parts metallized in tin bath and subjected to external stress.

Reduction of the coefficient of friction of niobium nitride coatings by the addition of bismuth

Composite coatings of niobium nitride containing bismuth inclusions were deposited using a dual magnetron sputtering system with independent power suppliers for each targets; Bi and Nb. The deposition was performed under and Ar/N2 atmosphere at a 2.3 flow rate ratio, which allows the stoichiometric NbN phase to be obtained. The aim of this work was to evaluate the effect of increasing concentrations of Bi, proposed as a lubricous second phase, in the structural, mechanical and tribological properties of niobium nitride (NbN) coatings, searching for a reduction in the coefficient of friction but trying to keep hardness values larger than the tool steels (>10 GPa). The power applied to the Nb target was fixed, while the power on the Bi target was increased; obtaining Bi atomic percentage values of 1.7, 4.9 and 8.4 at%. The Bi inclusions showed different sizes and distribution in the volume and surface of the coatings. The results indicated a reduction in the hardness from 30 GPa of the NbN coating to 13.9 GPa for the highest Bi concentration. However, a more significant reduction was observed for the coefficient of friction (CoF) from 0.8 of the NbN to 0.3 for Bi concentrations between 4.9 and 8.4 at%.

The impact of bismuth addition to sequential treatment on Helicobacter pylori eradication: A pilot study.

The success of the current anti-Helicobacter pylori (H. pylori) treatment protocols is reported to decrease by years, and research is needed to strengthen the H. pylori eradication treatment. Sequential treatment (ST), one of the treatment modalities for H. pylori eradication, includes amoxicillin 1 gr b.i.d and proton pump inhibitor b.i.d for first 5 days and then includes clarithromycin 500 mg b.i.d, metronidazole 500 mg b.i.d and a proton pump inhibitor b.i.d for remaining 5 days. In this study, we investigated efficacy and tolerability of bismuth addition in to ST. We included patients that underwent upper gastrointestinal endoscopy in which H. pylori infection was diagnosed by histological examination of antral and corporal gastric mucosa biopsy. Participants were randomly administered ST or bismuth containing ST (BST) protocols for the first-line H. pylori eradication therapy. Participants have been tested by urea breath test for eradication success 6 weeks after the completion of treatment. One hundred and fifty patients (93 female, 57 male) were enrolled. There were no significant differences in eradication rates for both intention to treat population (70.2%, 95% confidence interval [CI]: 66.3-74.1% vs. 71.8%, 95% CI: 61.8-81.7%, for ST and BST, respectively, p>0.05) and per protocol population (74.6%, 95% CI: 63.2-85.8% vs. 73.7%, 95% CI: 63.9-83.5% for ST and BST, respectively, p>0.05). Despite the undeniable effect of bismuth, there may be several possible reasons of unsatisfactory eradication success. Drug administration time, coadministration of other drugs, possible H. pylori resistance to bismuth may affect the eradication success. The addition of bismuth subcitrate to ST regimen does not provide significant increase in eradication rates.

Catalytic Deoxygenation of Guaiacol Using Methane

Guaiacol, produced by thermal degradation of lignin, represents a model compound for upgrading of fast pyrolysis bio-oils by deoxygenation. In our prior work, with Pt/C catalyst, such a process using H2 was studied. To overcome the high cost of H2, methane is used in this work to deoxygenate guaiacol. On Pt/C catalyst, in terms of guaiacol conversion and product distribution, methane is found to exhibit as good deoxygenation performance as H2. The lifetime of this catalyst, however, is short (<3 h). The lifetime of Pt–Bi/C catalyst is extended (no significant deactivation in 5 h), by addition of bismuth as a promoter. This work provides a new approach for bio-oil upgrading using methane as a reductant instead of hydrogen.