Conventional Noble Metal Catalysts Research Articles

Superlative Porous Organic Polymers for Photochemical and Electrochemical CO2 Reduction Applications: From Synthesis to Functionality.

To mimic the carbon cycle at a kinetically rapid pace, the sustainable conversion of omnipresent CO2 to value-added chemical feedstock and hydrocarbon fuels implies a remarkable prototype for utilizing released CO2. Porous organic polymers (POPs) have been recognized as remarkable catalytic systems for achieving large-scale applicability in energy-driven processes. POPs offer mesoporous characteristics, higher surface area, and superior optoelectronic properties that lead to their relatively advanced activity and selectivity for CO2 conversion. In comparison to the metal organic frameworks, POPs exhibit an enhanced tendency toward membrane formation, which governs their excellent stability with regard to remarkable ultrathinness and tailored pore channels. The structural ascendancy of POPs can be effectively utilized to develop cost-effective catalytic supports for energy conversion processes to leapfrog over conventional noble metal catalysts that have nonlinear techno-economic equilibrium. Herein, we precisely surveyed the functionality of POPs from scratch, classified it, and provided a critical commentary of its current methodological advancements and photo/electrochemical achievements in the CO2 reduction reaction.

Expedient alkyne semi-hydrogenation by using a bimetallic AgCu-C3N4 single atom catalyst.

Metal-catalyzed semi-hydrogenation of alkynes is an important step in organic synthesis to produce diverse chemical compounds. However, conventional noble metal catalysts often suffer from poor selectivity owing to over-hydrogenation. Here, we demonstrate a high-loading bimetallic AgCu-C3N4 single-atom catalyst (SAC) for alkyne semi-hydrogenation. The AgCu-C3N4 SACs exhibit higher activity and selectivity (99%) than their low-loading variants due to the synergistic interaction of heteronuclear Ag-Cu sites at small inter-site distances. Using a combination of techniques such as phenylacetylene-DRIFTS, H2-temperature programmed desorption and DFT calculations, we showed that the cooperative bimetallic interaction during alkyne semi-hydrogenation was achieved by isolated Ag centers as hydrogen activation sites and isolated Cu centers as alkyne activation sites. Our work highlights the importance of achieving high catalyst loading to reduce the inter-site distance in bimetallic SACs for cooperative interactions, which can potentially open new catalytic pathways for synthesizing fine chemicals and pharmaceuticals.

Value addition of MXenes as photo-/electrocatalysts in water splitting for sustainable hydrogen production.

The energy transition from fossil fuel-based to renewable energy is a global agenda. At present, a major concern in the green hydrogen economy is the demand for clean fuels and non-noble materials to produce hydrogen through water splitting. Researchers are focusing on addressing this concern with the help of the development of appropriate non-noble-based photo-/electrocatalytic materials. A new class of two-dimensional materials, MXenes, have recently shown tremendous potential for water splitting to produce H2via a photoelectrochemical process. The unique properties of emerging 2D MXene materials, such as hydrophilic surface functionalities, higher surface-to-volume ratios, and inherent flexibility, present these materials as appropriate photo-/electrocatalytic materials. Unique value addition and innovative strategies such as the introduction of end-group modification, heterojunctions, and nanostructure engineering have shown the potential of MXene materials as emerging photo-/electrocatalysts for water splitting. When integrated with conventional noble metal catalysts, MXene-based catalysts demonstrated a lower overpotential for hydrogen and oxygen evolution reactions and a remarkable boost in performance for enhanced H2 production rates surpassing those of pristine noble metal-based catalysts. These promote future perspectives for the utilization of chemically synthesized MXenes as alternative photo-/electrocatalysts. Future research direction should focus on MXene synthesis and utilization for surface modification, composite formation, stabilization, and optimization in synthesis methods and post-synthesis treatments. This review highlights the progress in the understanding of fundamental mechanisms and issues associated with water splitting, influencing factors of MXenes, their value addition role, and application strategies for water splitting, including performance, challenges, and outlook of MXene-based photo-/electrocatalysts, in the last five years.

Manganese, iron co-doped Ni2P nanoflowers as a powerful electrocatalyst for oxygen evolution reaction

MnFe-Ni 2 P/NF is synthesized by a simple hydrothermal and subsequent phosphorylation reaction. The prepared material has excellent OER activity with an overpotential of 220 mV at a current density of 10 mA cm −2 . • Trimetallic transition metal phosphide nanoflowers are in-situ synthesized on Ni foam. • The unique flower-like structure provides more active sites for the OER reaction. • MnFe-Ni 2 P/NF shows high catalytic stability for OER in alkaline media. • MnFe-Ni 2 P/NF shows higher catalytic activity than that of bimetallic phosphides. The development of abundant, high-performance electrocatalysts for oxygen evolution reactions (OER) is an ongoing challenge to renewable energy. Herein, we rationally synthesized a manganese (Mn) and iron (Fe) doped Ni 2 P nanosheet (MnFe-Ni 2 P) as a highly efficient electrocatalyst for OER in alkaline solution by a simple hydrothermal method and phosphorylation. The bimetal-doped phosphide nanosheets are directly grown on the conductive nickel foam (NF) to form a 3D structure which facilitates to expose active sites as much as possible. Due to the electron interaction between the Mn, Fe and Ni, which contributes to ion diffusion and gas release, trimetallic MnFe-Ni 2 P/NF delivers an extremely low overpotential of 220 mV at 10 mA cm −2 and a small Tafel slope of 53 mV dec −1 in alkaline electrolyte towards OER. Furthermore, the excellent stability of MnFe-Ni 2 P/NF lasts for at least 24 h at a high current density of 50 mA cm −2 without much deviation. We demonstrate that the trimetallic MnFe-Ni 2 P/NF benefits from the doping of Mn, Fe elements and the unique flower-like structure, exhibits more effective electrocatalytic activity compare to conventional noble metal catalysts and Ni 2 P series materials.

Smart Designs of Mo Based Electrocatalysts for Hydrogen Evolution Reaction

As a sustainable and clean energy source, hydrogen can be generated by electrolytic water splitting (i.e., a hydrogen evolution reaction, HER). Compared with conventional noble metal catalysts (e.g., Pt), Mo based materials have been deemed as a promising alternative, with a relatively low cost and comparable catalytic performances. In this review, we demonstrate a comprehensive summary of various Mo based materials, such as MoO2, MoS2 and Mo2C. Moreover, state of the art designs of the catalyst structures are presented, to improve the activity and stability for hydrogen evolution, including Mo based carbon composites, heteroatom doping and heterostructure construction. The structure–performance relationships relating to the number of active sites, electron/ion conductivity, H/H2O binding and activation energy, as well as hydrophilicity, are discussed in depth. Finally, conclusive remarks and future works are proposed.

Investigation of Synergistic Effects between Co and Fe in Co3-xFexO4 Spinel Catalysts for the Liquid-Phase Oxidation of Aromatic Alcohols and Styrene

Transition metal oxides are attractive catalyst alternatives in liquid-phase oxidation reactions due to their lower cost and higher abundance compared with conventional noble metal catalysts. We investigated the catalytic properties of a systematic series of Co3-xFexO4 spinel catalysts synthesized by a hard-templating method, which were applied in the liquid-phase oxidation of styrene, benzyl alcohol and cinnamyl alcohol. O2 and tert-butyl hydroperoxide (TBHP) were used as the oxidants in a comparative manner. For alcohol oxidation, TBHP leads to similar or slightly higher selectivity to the corresponding aldehydes compared with O2. For the activation of C=C bonds, TBHP favors the oxidative cleavage pathway, while O2 favors the epoxidation pathway. The comparison of the catalytic performance revealed that the activity of Co3O4 does not benefit from Fe doping using O2 as the oxidant, while the substitution of Fe ≤ 10 % in the spinel structure is beneficial when TBHP is used. This is attributed to the different activation mechanisms of the oxidizing agents, being spin transfer in case of O2 and partial decomposition in case of TBHP. Heterogeneity tests and reusability studies demonstrated the stability of the spinel catalysts.

Engineering the activity of CoNx-graphene for hydrogen evolution

The sustainable generation of H2 from water electrolysis is a promising approach to alleviating current energy crisis and environmental pollution. However, the efficiency of such a system is limited by the conventional noble metal catalysts. Herein, using first-principle calculations, we demonstrate the potential of non-precious Co and N-codoped graphene systems (CoNx-N/O-gra, x = 1–4) in efficiently catalyzing the hydrogen evolution reaction (HER). The findings showed that the activity of the Co sites was influenced by the concentration and configuration of N dopants, as well as the coordination environment of Co atom. From the volcano curve, obtained by plotting the exchange current as a function of the adsorption free energy, optimal performance was achieved on CoN4-gra, which was attributed to the moderate adsorption of CoN4-gra towards H. The electronic structures analyses confirmed that the hybridization between Co sp orbital and H s orbital played key role in tuning the interactions between the catalysts and H, which could be regulated by the coordination environment of Co. The present findings highlight the potential of non-precious metal/non-metal-codoped graphene as HER catalysts and offers an effective approach to tune the HER activity by modifying the coordination environment of the metal atoms.

Mild Deoxygenation of Sulfoxides over Plasmonic Molybdenum Oxide Hybrid with Dramatic Activity Enhancement under Visible Light.

Harvesting solar light to boost commercially important organic synthesis still remains a challenge. Coupling of conventional noble metal catalysts with plasmonic oxide materials which exhibit intense plasmon absorption in the visible light region is a promising option for efficient solar energy utilization in catalysis. Herein, we for the first time demonstrate that plasmonic hydrogen molybdenum bronze coupled with Pt nanoparticles (Pt/H xMoO3- y) shows a high catalytic performance in the deoxygenation of sulfoxides with 1 atm of H2 at room temperature, with dramatic activity enhancement under visible light irradiation relative to dark conditions. The plasmonic molybdenum oxide hybrids with strong plasmon resonance peaks pinning at around 556 nm are obtained via a facile H-spillover process. Pt/H xMoO3- y hybrid provides excellent selectivity for the deoxygenation of various sulfoxides as well as pyridine N-oxides, in which drastically improved catalytic efficiencies are obtained under the irradiation of visible light. Comprehensive analyses reveal that oxygen vacancies massively introduced via a H-spillover process are the main active sites, and the reversible redox property of Mo atoms and strong plasmonic absorption play key roles in this reaction. The catalytic system works under extremely mild conditions and can boost the reaction by the assistance of visible light, offering an ultimately greener protocol to produce sulfides from sulfoxides. Our findings may open up a new strategy for designing plasmon-based catalytic systems that can harness visible light efficiently.

Rational Design of Materials for Electrocatalysis Energy Storage and Conversion Technologies

Increasing the global energy demand as well as the carbon dioxide (CO2) level in the atmosphere caused by burning fossil fuel as the main source of energy motivate the development of green energy technologies. However, the real activity improvement for these technologies is mainly impeded by intermittent nature of renewable energy technologies. One smart approach to overcome this issue is to store energy into the chemical bonds1–6 using inexpensive and efficient energy conversion and storage technologies. In these systems, energy can be converted or stored into chemical bonds as a form of fuels or electricity using renewable energy sources, e.g., solar and wind energy7–9. Despite recent progress, the development of these systems is advanced far more slowly due to the expensive and less efficient materials employed in these technologies. Here, I will present my aim to design, synthesis, and characterization of inexpensive earth-abundant transition metal dichalcogenide class of materials suitable for energy conversion and storage systems. I have tested the performance of this class of catalysts for the carbon dioxide (CO2) reduction reaction, oxygen reduction, oxygen evolution reactions. The results indicate (i) 100 times higher turn over frequency- per atom activity- far exceeding the performance of state-of-the-art catalysts for CO2 reduction reaction, and (ii) a highly efficient bi-functional catalyst for oxygen reduction and evolution reactions in the aprotic media compared to conventional noble metal catalysts used for the same application (e.g., Platinum and Gold). I also tested the performance of molybdenum disulfide nanoflakes (MoS2 NFs) -a versatile member of TMDCs- in lithium-air batteries known as a promising alternative to the conventional lithium-ion batteries. The results indicate that MoS2 NFs in the ionic liquid EMIM-BF4 electrolyte performs remarkably well in the actual air environment with a small discharge/charge potential gap as well as good stability and cyclability up to 550 cycles without any evidence of failure. I will discuss these and other results including the potential of our recent discovery to open a new route towards energy efficient, highly active and cost-effective energy storage and conversion systems to replace fossil fuels.

3D Synergistically Active Carbon Nanofibers for Improved Oxygen Evolution

Developing earth‐abundant and active electrocatalysts for the oxygen evolution reaction (OER) as replacements for conventional noble metal catalysts is of scientific and technological importance for achieving cost‐effective and efficient conversion and storage of renewable energy. However, most of the promising candidates thus far are exclusively metal‐based catalysts, which are disadvantaged by relatively restricted electron mobility, corrosion susceptibility, and detrimental environmental influences. Herein, hierarchically porous nitrogen (N) and phosphorus (P) codoped carbon nanofibers directly grown on conductive carbon paper are prepared through an electrochemically induced polymerization process in the presence of aniline monomer and phosphonic acid. The resultant material exhibits robust stability (little activity attenuation after 12 h continuous operation) and high activity with low overpotential (310 mV at 10 mA cm−2) toward electrocatalytic oxygen production, with performance comparable to that of the precious iridium oxide (IrO2) benchmark. Experimental measurements reveal that dual doping of N and P can result in an increased active surface area and abundant active sites in comparison with the single doped and pristine carbon counterparts, and density functional theory calculations indicate that N and P dopants can coactivate the adjacent C atoms, inducing synergistically enhanced activity toward OER.

(Keynote) Enzymatic Biofuel Cell Based on Porous Carbon Materials

Enzymatic biofuel cells (EBFCs) are a type of fuel cells, which employ enzymes instead of conventional noble metal catalysts. The working principle is the same as in conventional polymer electrolyte membrane fuel cells, namely fuel is oxidized at the anode side and the electrons reach the cathode, where they combine with an oxygen to water. EBFCs are promising for sustainable green energy applications; however, they are still at an early stage of development, with many yet-to-be-resolved fundamental scientific and engineering problems. Two critical problems are short lifetime and poor power density, both of which are related to enzyme stability, electron transfer rate, and enzyme loading. To achieve the practical application of EBFCs, a promising approach is to use porous carbon materials. Strategies for the designing of hierarchically structured supports composed of mesoporous and macroporous are considered: the large surface area of mesoporous materials can increase the enzyme loading and electron transfer efficiency, and the macropores enable the efficient fuel transport. Our recent paper demonstrated that Magnesium oxide (MgO)-templated porous carbon forms are promising candidates as electrode materials for the elaboration of efficient bioelectrochemical devices. MgO-templated mesoporous carbon (MgOC, mean pore diameter 10, 20, 40, 80 nm) were used to increase the effective specific surface area for specific enzyme immobilization. MgOC particles were deposited on a current collector by an electrophoretic deposition method to generate micro meter-scale macropores to improve the mass transfer of glucose and electrolyte (buffer) ions. To create a glucose bioanode, the porous-carbon-modified electrode was further coated with a biocatalytic hydrogel composed of a conductive redox polymer, flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH), and a cross-linker. The electrode coated with FAD-GDH and a redox polymer showed a 33-fold increase in glucose oxidation current density (ca. 100 mA cm−2) compared to that of the flat electrode. MgOC-modified electrode can be applied for the biocathode using bilirubin oxidase (BOD) as an oxygen reduction reaction catalysts. Our recent wearable EBFC based on MgOC will be presented. FAD-GDH was used as an anodic catalyst. 1,4-naphtoquinone was modified on the MgOC mesopore surface. Bilirubin oxidase and ABTS mediator were modified on the MgOC surface. Aiming at the application of EBFCs to the wearable power devices, we modified the MgOC on the surface of flexible carbon cloth. The cell operation was initiated after addition of 0.4 mL of 1 M phosphate buffer solution containing various concentrations of glucose, ranging from 0.1 – 3 M. The maximum output power density per geometric surface area was 2 mW cm-2, which was limited by the cathode performance, especially O2 supply from the air. The operation time, i.e. cell capacity, was quantitatively determined by the mole number of applied glucose evaluated by galvanostatic experiments at 0.25 – 4 mA cm-2 of constant current density, indicating that the capacity was determined by the consumption of β-d-glucose. After consumption of the fuel, the cells were able to restart by adding the glucose solution. The operation time linearly depended on the mole number of glucose added. In this presentation, recent developments in EBFCs technology using porous carbon materials are highlighted. The essential properties of the resulting materials with respect to the EBFC application are also discussed. A combination of electron transfer technology and porous carbon material would be helpful in achieving a much higher and stable current output, thus contributing to a practical advance in the sustainable energy field.

Guayule (Parthenium argentatum) pyrolysis biorefining: Production of hydrocarbon compatible bio-oils from guayule bagasse via tail-gas reactive pyrolysis

Abstract Guayule (Parthenium argentatum) is a woody desert shrub cultivated in the southwestern United States as a source of natural rubber, organic resins, and high energy biofuel feedstock from crop residues. We used guayule bagasse, the residual biomass after latex extraction as feedstock in a pyrolysis process that employs a reactive gas environment to formulate a special intermediate bio-oil product that allows use of conventional hydrotreating with conventional noble metal catalysts and a simple distillation process to synthesize hydrocarbon (drop-in) fuels. The said guayule-bagasse tail gas reactive pyrolysis (TGRP) process comprises pyrolyzing the guayule bagasse in a fluidized-bed reactor in the presence of a reactive and flammable tail gas (comprising CO ∼ 30%, CH4 ∼ 16%, CO2 ∼ 40%, H2 ∼ 10%, C2H4 ∼ traces) generated in the pyrolysis process and without the use of catalyst to produce bio-oil with C/O molar ratio of 14/1 in organic yields of 34–40 wt% having an energy content of 31–37.5 MJ/kg. When we further processed the said bio-oil by centrifugation, we obtained 85 wt% yield and further 50–65 wt% yields following a continuous hydrotreatment over common noble metals (Pt, Ru or Pd) on a carbon support. Distillation of this mixture yielded >95 wt% hydrocarbon liquid fuel mixture comprising 30.4% gasoline (C5–C7), 37% jet (C8–C12) and 24% diesel (C13–C22). Analysis of a composite mixture of the hydrotreated product from the bagasse showed the majority of the sample (66%) was C12 and below, which falls within the gasoline (naphtha) range with the greatest fraction of naphtha falling within the C8–C10 range. Beyond C12, the molecular weights increased through the diesel range (34%), with C37 being the highest observable molecular weight. The product met several ASTM standards for drop-in fuels, but the sulfur content (primarily due to latex extraction additives) was relatively high at around 300 ppm, indicating that hydrodesulfurization may be required to be infrastructure ready.

Novel and Effective Copper–Aluminum Propane Dehydrogenation Catalysts

Novel and Effective Copper–Aluminum Propane Dehydrogenation Catalysts

A Review on Preferential Oxidation of Carbon Monoxide in Hydrogen Rich Gases

In this review, recent works on the preferential oxidation of carbon monoxide in hydrogen rich gases for fuel cell applications are summarized. H2 is used as a fuel for polymer-electrolyte membrane fuel cell (PEMFC). It is produced by reforming of natural gas or liquid fuels followed by water gas shift reaction. The produced gas consists of H2, CO, and CO2. In which CO content is around 1%, which is highly poisonous for the Pt anode of the PEMFC so that further removal of CO is needed. Catalytic preferential oxidation of CO (CO-PROX) is one of the most suitable methods of purification of H2 because of high CO conversion rate at low temperature range, which is preferable for PEMFC operating conditions. Catalysts used for COPROX are mainly noble metal based; gold based and base metal oxide catalysts among them Copper-Ceria based catalysts are the most appropriate due to its low cost, easy availability and result obtained by these catalysts are comparable with the conventional noble metal catalysts. © 2011 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Enthalpy recovery of gases issued from H 2 production processes: Activity and stability of oxide and noble metal catalysts in oxidation reaction under highly severe conditions

Oxidation activity and stability under reaction was investigated for a series of mixed oxide catalysts, doped or not by a precious metal (Pd, Pt). The reaction feedstock, containing CO, H 2, CH 4, CO 2 and H 2O, simulated gases issued from H 2 production processes for fuel cells. Contrarily to conventional noble metal catalysts, mixed oxide samples present generally good stability under reaction at high temperature. The activities measured for the perovskite and hexaaluminate catalysts, are however largely lower than that of the reference Pd/Al 2O 3 catalyst. High activities were obtained after impregnation of 1.1 wt.% Pd or 0.8 wt.% Pt on the hexaaluminates samples. Even if Pd/Al 2O 3 was found to present a high activity, this sample suffered from drastic deactivation at 700 °C. Better stability were obtained on perovskite. Furthermore, doping hexaaluminate by Pt led to samples with good activities and high stability. Even if better activities were obtained by doping the hexaaluminate samples by Pd, the Pd/BaAl 12O 19 strongly deactivated, as it was previously observed for the reference catalyst. Interestingly, this Pd deactivation was not observed when Pd was impregnated on the Mn substituted hexaaluminate, leading to a stable and active catalyst. This suggests that it is possible to stabilize the palladium in its oxidized form at high temperature (700 °C) on the surface of some supports.

Encapsulated laccase electrodes for fuel cell cathodes

Biocatalysts are an attractive alternative to conventional noble metal catalysts for fuel cell cathodes. In principle, they combine the possibility of more efficient operation (lower intrinsic overpotential) with the benefits of renewability, selectivity and low temperature operation. In order for these benefits to be realized in a practical cathode design, however, both improved sources of suitable oxygen-reducing oxidoreductases, and improved electrode designs are required. In this paper, we discuss the preparation and performance of cathodes based on the “encapsulation” of a laccase enzyme with silica or organic polymer binders on porous carbon paper supports. We show that these electrodes are both electrochemically efficient and stable to leaching or degradation over millions of turnovers. We also show that these electrodes can be used with conventional Pt-based anodes in a direct methanol fuel cell structure.

Current densities from electrocatalytic oxygen reduction in laccase/ABTS solutions

Biocatalysts are an attractive alternative to conventional noble metal catalysts for fuel cell cathodes. In principle, they combine the possibility of more efficient operation (lower intrinsic overpotential) with the benefits of renewability and low temperature operation. In this paper we discuss some fundamental biochemistry and electrochemistry of one cathode system that has attracted some interest in the biofuel cell community, laccase as catalyst with 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as mediator. We focus on one laccase preparation from Trametes versicolor, and demonstrate that steady state electrocatalytic oxygen reduction currents can be modeled using the measured intrinsic properties of the enzyme ( k cat, K M) and mediator ( D M). We then discuss some of the implications of this modeling for practical electrode design.

98/02128 Results of laboratory and industrial tests of pitch coke in the manufacture of carbon structural materials

Guayule (Parthenium argentatum) is a woody desert shrub cultivated in the southwestern United States as a source of natural rubber, organic resins, and high energy biofuel feedstock from crop residues. We used guayule bagasse, the residual biomass after latex extraction as feedstock in a pyrolysis process that employs a reactive gas environment to formulate a special intermediate bio-oil product that allows use of conventional hydrotreating with conventional noble metal catalysts and a simple distillation process to synthesize hydrocarbon (drop-in) fuels. The said guayule-bagasse tail gas reactive pyrolysis (TGRP) process comprises pyrolyzing the guayule bagasse in a fluidized-bed reactor in the presence of a reactive and flammable tail gas (comprising CO ∼ 30%, CH4 ∼ 16%, CO2 ∼ 40%, H2 ∼ 10%, C2H4 ∼ traces) generated in the pyrolysis process and without the use of catalyst to produce bio-oil with C/O molar ratio of 14/1 in organic yields of 34–40 wt% having an energy content of 31–37.5 MJ/kg. When we further processed the said bio-oil by centrifugation, we obtained 85 wt% yield and further 50–65 wt% yields following a continuous hydrotreatment over common noble metals (Pt, Ru or Pd) on a carbon support. Distillation of this mixture yielded >95 wt% hydrocarbon liquid fuel mixture comprising 30.4% gasoline (C5–C7), 37% jet (C8–C12) and 24% diesel (C13–C22). Analysis of a composite mixture of the hydrotreated product from the bagasse showed the majority of the sample (66%) was C12 and below, which falls within the gasoline (naphtha) range with the greatest fraction of naphtha falling within the C8–C10 range. Beyond C12, the molecular weights increased through the diesel range (34%), with C37 being the highest observable molecular weight. The product met several ASTM standards for drop-in fuels, but the sulfur content (primarily due to latex extraction additives) was relatively high at around 300 ppm, indicating that hydrodesulfurization may be required to be infrastructure ready.

Electrolytes for methanol-air fuel cells. 11. The electro-oxidation of methanol in trifluoromethane-sulphonic acid monohydrate and aqueous solutions of trifluoromethane-sulphonic acid

Trifluoromethanesulphonic acid monohydrate CF3SO3H.H2O and its aqueous solutions have been evaluated as an electrolyte for methanol electro-oxidation. The performances of conventional noble metal catalysts in the pure monohydrate are very poor compared with those in 3 M sulphuric acid. This is contrary to previously published literature data, and possible reasons for the discrepancy are given. In aqueous solutions of CF3SO3H at concentrations between 10 and 50%wt. considerably improved performance is obtained and at 60° C the activities of the catalysts are in most cases slightly higher than in 3 M H2SO4. In addition the poisoning effect of acid radicals is considerably less in CF3SO3H than in H2SO4 solutions. Above 60° C, however, the aqueous CF3SO3 anion decomposes to produce sulphur, which poisons the noble metal catalysts.