Commercial Platinum Catalyst Research Articles

Nanopartículas de cobalto y cobre sobre óxido de grafeno parcialmente reducido con espaciadores de nanotubos de carbono o carbón vulcano como catalizadores para la reacción de reducción de oxígeno

In this paper, we reported the synthesis of Co and Cu nanoparticles (NPs) supported on partially reduced graphene oxide (M/rGO), with the incorporation of spacers as multi-walled carbon nanotubes (MWCNT) and carbon black (CB) among graphene interlayers to generate carbon nanocomposites. The oxygen reduction reaction (ORR) polarization curves show that the use of MWCNT as spacer improves the current density up to 6.9 times for Co NPs and up to 3.5 times for Cu NPs materials. Also, the charge transfer resistance decreases using CB: 950 times for Co NPs and 68 for Cu NPs materials. All carbon-nanocomposites present upgraded stability comparing to the commercial platinum catalyst (Pt/C).

Two-layer anode electrode with non-noble catalysts as CO tolerant structure for PEM fuel cell

Many studies on platinum-based dual-metal or multi-metal alloys catalysts are underway to strengthen the resistance of the anode catalyst layer against hydrogen fuel contamination, especially carbon monoxide. The change in the structure of the catalyst layer can also be a new and effective way to remove Carbon Monoxide. In the few multi-layer electrode structure reported cases, ruthenium metal is used in the outer layer, for sieving the Carbon Monoxide molecules before reaching to the Pt/C catalyst in the inner layer. In this study, we make two-layer catalyst anode electrode with SnO2/C and Sn20.Co80/C in outer layer and commercial Pt/C in inner layer. The performance of these electrodes for Carbon Monoxide electro-oxidation evaluate by cyclic voltammetry and the results compare with the activity of an electrode with commercial platinum catalyst only. Our two-layer electrodes have the same efficiency as commercial platinum electrodes and even more for pure hydrogen oxidation and much better activity for pure Carbon Monoxide electro-oxidation at low potentials, in half-cell media. These electrodes have better stability for Carbon Monoxide oxidation after 100 cycles along with Carbon Monoxide gas bubbling and electrode with bi-metal catalyst in outer layer has almost no loss in performance.

P-doped mesoporous carbons for high-efficiency electrocatalytic oxygen reduction

Chemically modified carbonaceous materials have attained utmost attention in the fields of renew-able energy storage and conversion, due to the controllable physicochemical properties, tailorable micro-/nanostructures, and respectable stability. Herein, P-doped mesoporous carbons were syn-thesized by using F127 as the soft template, organophosphonic acid as the P source and phenolic resin as the carbon source. Small amounts of iron species were introduced to act as a graphitization catalyst. The synthesized carbons exhibit the well-defined wormhole-like pore structure featuring high specific surface area and homogenously doped P heteroatoms. Notably, introducing iron spe-cies during the synthesis process can optimize the textural properties and the degree of graphitiza-tion of carbon materials. The doping amount of P has an important effect on the porous structure and the defect degree, which correspondingly influence the active sites and the oxygen reduction reaction (ORR) activity. The resultant material presents superior catalytic activity for the ORR, together with remarkably enhanced durability and methanol tolerance in comparison with the commercial Platinum catalyst, demonstrating the possibility for its use in electrode materials and electronic nanodevices for metal-air batteries and fuel cells.

In Situ NMR Spectroscopic Investigations of the Electrocatalytic Ethanol Oxidation Reaction

During the past decades, the development of alternative energy sources became increasingly important because the growing consumption of non-regenerative fossil energy poses a threat to the environment. Hence, the development of fuel cells plays an important role for E-mobility and further portable and stationary applications. Hydrogen is highly efficient as a fuel, in particular in a polymer electrolyte fuel cell. It can, however, only be used to a limited extent because of its expensive and hazardous production and storage. Therefore, the use of hydrogen carriers, such as alcohols, in direct alcohol fuel cells is an approach to tackle this problem. [1] The electrochemical oxidation of such small organic molecules in alkaline media has been much less studied, because membranes, which are stable under these conditions, have not been developed. [2] In the last 20 years the alkaline fuel cells has been studied extensively, because high performance membranes are being developed. Additionally, the faster kinetics of the Oxidation reaction in alkaline medium allows the use of non-noble metal catalysts. [3] Methanol is the smallest alcohol and has already been intensively studied as a fuel due to its less complex oxidation mechanism. [4] In contrast, ethanol shows a significantly more complex reaction at the catalyst surface. Nevertheless, the higher energy density and availability in large quantities by fermentation from renewable resources makes it a highly promising alternative. Breaking the carbon-carbon-bond is the most challenging part of the complete oxidation of ethanol. If this bond cleavage is not complete, a considerable amount of by-products must be expected, depending on the catalyst. Thus, it is essential to elucidate the adsorption and reaction mechanisms on the surface of the catalyst for the development of direct ethanol fuel cells with different catalysts. [5] Identification and quantification of intermediates and products of the electrocatalytic oxidation of ethanol in alkaline medium are desirable in terms of understanding the underlying mechanism. In situ NMR spectroscopic measurements allow to detect and quantify the entire range of oxidation products non-invasively and with high chemical specificity. [6] We have developed methods to follow the electrochemical oxidation of ethanol in situ by NMR spectroscopy. For the implementation of these in situ measurements, special Pouch Cells were constructed and optimized. These Pouch Cells consist of carbon-based electrodes, which have been coated for example with a commercial platinum catalyst. The main products of the ethanol oxidation were detected by in situ NMR spectroscopy. [1] F. Vigier, C. Coutanceau, F. Hahn, E. M. Belgsir, C. Lamy, J. Electroanal. Chem. 2004, 563, 81. [2] S. C. S. Lai, M. T. M. Koper, Phys. Chem. Chem. Phys. 2009, 11, 10446. [3] G. F. McLean, T. Niet, S. Prince-Richard, N. Djilali, Int. J. Hydrogen Energ. 2002, 27, 507. [4] J. W. Gosselink, Int. J. Hydrogen Energ. 2002, 27, 1125. [5] B. Pierozynski, Int. J. Electrochem. Sci. 2012, 7, 4261. [6] E. G. Sorte, Y. Y. J. Tong, J. Electroanal. Chem-, 2016, 769, 1.

Flue Gas Derived Carbon Electrocatalysts for Enhancing Oxygen Reduction Reaction

Flue gas was directly converted into carbon materials with the doping of iron, boron and nitrogen atom. The B-N doping was achieved in a single step with the carbonization of flue gas and subsequently, the Fe atom was incorporated into the material using the iron precursor (FeCl3). The synthesized Fe-N-B co-doped carbon materials showed enhanced electrochemical activity for oxygen reduction reaction (ORR), which is comparable to that of commercial platinum catalysts. The effect of various FeN/C ratios by varying the amount of iron species in the synthesis step was investigated, and the clear correlation between the doping of Fe/N and electrochecmical activity was confirmed. The optimized iron weight ratio was 33 % due to the existence of Fe-N pyridinic bonding in the carbon lattices without agglomeration of Fe species. The high electrocatalytic activity toward ORR and long-term durability for 10,000 cycles of synthesized Fe-N-C composites indicate that flue gas itself can be an effective precursor for efficient carbon-based electrocatalysts.

Nanoscale Catalysts of Oxygen Reduction Based on Bimetallic Clusters in Hydrogen–Air Fuel Cell Operating Conditions

The electrochemical and power characteristics of the membrane electrode assemblies with PtCo/C, PtMn/C, PtZn/C, and PtNi/C cathode bimetallic catalysts, prepared from PtCo(CH3СO2)4(СH3СOОН), PtNi(CH3СO2)4(СH3СOОН), PtMn(CH3СO2)4(H2O), and PtZn(CH3СO2)4(СH3СOОН) bimetallic clusters, as a component of hydrogen–oxygen and hydrogen–air fuel cells, were studied. It is shown that various types of platinum-metal alloys with the ratio Pt : M = 1 : 1 (where M = Co, Ni, Mn, Zn) uniformly distributed over the surface of the support are formed after thermal degradation of the bimetallic clusters deposited on carbon black, and the catalyst grain size is 2–5 nm. The synthesized PtCo/C, PtMn/C, and PtZn/C catalysts are superior to a commercial platinum catalyst in terms of their high specific activity and, therefore, are promising for application in hydrogen–air fuel cells.

Ruthenium atomically dispersed in carbon outperforms platinum toward hydrogen evolution in alkaline media

Hydrogen evolution reaction is an important process in electrochemical energy technologies. Herein, ruthenium and nitrogen codoped carbon nanowires are prepared as effective hydrogen evolution catalysts. The catalytic performance is markedly better than that of commercial platinum catalyst, with an overpotential of only −12 mV to reach the current density of 10 mV cm-2 in 1 M KOH and −47 mV in 0.1 M KOH. Comparisons with control experiments suggest that the remarkable activity is mainly ascribed to individual ruthenium atoms embedded within the carbon matrix, with minimal contributions from ruthenium nanoparticles. Consistent results are obtained in first-principles calculations, where RuCxNy moieties are found to show a much lower hydrogen binding energy than ruthenium nanoparticles, and a lower kinetic barrier for water dissociation than platinum. Among these, RuC2N2 stands out as the most active catalytic center, where both ruthenium and adjacent carbon atoms are the possible active sites.

Platinum-trimer decorated cobalt-palladium core-shell nanocatalyst with promising performance for oxygen reduction reaction

Advanced electrocatalysts with low platinum content, high activity and durability for the oxygen reduction reaction can benefit the widespread commercial use of fuel cell technology. Here, we report a platinum-trimer decorated cobalt-palladium core-shell nanocatalyst with a low platinum loading of only 2.4 wt% for the use in alkaline fuel cell cathodes. This ternary catalyst shows a mass activity that is enhanced by a factor of 30.6 relative to a commercial platinum catalyst, which is attributed to the unique charge localization induced by platinum-trimer decoration. The high stability of the decorated trimers endows the catalyst with an outstanding durability, maintaining decent electrocatalytic activity with no degradation for more than 322,000 potential cycles in alkaline electrolyte. These findings are expected to be useful for surface engineering and design of advanced fuel cell catalysts with atomic-scale platinum decoration.

Controllable active sites and facile synthesis of cobalt nanoparticle embedded in nitrogen and sulfur co-doped carbon nanotubes as efficient bifunctional electrocatalysts for oxygen reduction and evolution reactions

Abstract Development of efficient and promising bifunctional electrocatalysts for oxygen reduction and evolution reactions is desirable. Herein, cobalt nanoparticles embedded in nitrogen and sulfur co-doped carbon nanotubes (Co@NSCNT) were prepared by a facile pyrolytic treatment. The cobalt nanoparticles and co-doping of nitrogen and sulfur can improve the electron donor-acceptor characteristics of the carbon nanotubes and provide more active sites for catalytic oxygen reduction and evolution reactions. The prepared Co@NSCNT, annealed at 900 °C, showed excellent electrocatalytic performance and better durability than commercial platinum catalysts. Additionally, Co@NSCNT-900 catalysts exhibited comparable onset potentials and Tafel slopes to ruthenium oxide. Overall, Co@NSCNT showed high activity and improved durability for both oxygen evolution and reduction reactions.

Promoted activity of nitrogen-doped activated carbon as a highly efficient oxygen reduction catalyst in microbial fuel cells

Despite the wide application of activated carbon (AC) as cathode electrocatalyst in microbial fuel cell (MFC), the enhancement of its catalytic activity is crucial to reduce its high loading on air-cathode. Herein, we synthesize nitrogen-doped activated carbon (NAC) by pyrolyzing phthalocyanine (Pc) adsorbed on AC to develop an efficient oxygen reduction reaction (ORR) electrocatalyst. The optimized mass ratio of AC to Pc improves the crystalline structure and porous structure of the NAC. Elemental analysis indicates that this material contains appropriate content of pyrrolic and pyridinic types of nitrogen and oxygen species. The NAC shows an ORR onset potential of 0.468 V (vs. Standard hydrogen electrode), an electron transfer number of 3.90, and high electrochemically accessible surface area, thereby illustrating enhanced electrocatalytic activity in the neutral medium relative to alkali-treated activated carbon (b-AC) and commercial platinum catalyst. Owing to the high activity, a small amount of NAC with a loading of 15 mg cm− 2 on the air-cathode of MFC is sufficient to achieve the maximum power density of 1026.07 ± 10.83 mW m− 2, which is higher than that of b-AC and comparable to platinum catalyst. The reduced loading of NAC indicates that the material can be used as cathode electrocatalyst for the ongoing effort to scale up MFC in the future.

MnOx–CeO2 mixed oxides for diesel soot oxidation: a review

Catalytic diesel particulate filter is an efficient equipment for particulate matters control downstream of a diesel engine. MnOx–CeO2 mixed oxides are a potential alternative of the high cost commercial platinum catalyst. However, the poor thermal stability and sulfur resistance are two issues challenging its application. Additionally, the mechanism of synergistic effect between manganese oxide and ceria still remained debatable. Here, the catalysis mechanisms in the presence/absence of NOx were reviewed. The origins of synergistic effects were discussed based on whether the solid solutions formed or not. Meanwhile, different kinds of metal modifications were summarized and their promotion influences on the thermal stability and sulfur resistance were clarified in detail.

Phosphor and Nitrogen Codoped Rutile TiO2 on TiN for Oxygen Reduction Reaction in Acidic Media

Oxidative environments of acidic polymer electrolyte fuel cell (PEFC) cathodes have been a barrier to the development of active and stable platinum group metal (PGM)-free catalysts. In an alkaline environment, many non-PGM catalysts have exhibited higher oxygen reduction reaction (ORR) activity in comparison with commercial carbon-supported platinum (Pt/C) catalysts. In most cases, the higher activity of non-PGM catalysts has been reported at higher non-PGM catalyst loading than Pt/C. But in some recent reports, non-PGM catalysts displayed higher activity at catalyst loading identical to that of Pt/C.1,2 Due to the difference in reaction mechanism, such high ORR activity has not been reported in acidic PEFC cathodes. Thus scarce and high cost carbon supported platinum cobalt catalyst has been used in automotive PEFCs and the reduction of the usage is still needed for the widespread use.3 Stability is another critical factor to introduce PEFCs into global automotive markets as corrosion of carbon supports during startup/shutdown of vehicles has been more serious than platinum dissolution.4 We therefore recently developed a non-PGM catalyst free from carbon supports using titanium. The bulk of the catalyst is TiN whereas the surface was oxidized naturally to form so-called titanium oxynitride (TiO x N y ).5,6 The optimization of the synthesis conditions enhanced the ORR activity to the level of the best carbon-supported oxide-based catalyst, zirconium oxynitride on multiwalled carbon nanotube7 in 0.1 mol dm–3 H2SO4 solution.6 The activity did not change after 20 000 potential cycles between 0.6 and 1.0 V versus reversible hydrogen electrode, and the aforementioned stability was significantly improved from the previously reported carbon-supported TiO x N y .8 The disadvantage of the TiO x N y catalyst is small surface area to require high loading of 2.0 mg cm–2 for evaluating the ORR activity.5,6 For the reduction of catalyst loading via increasing the surface area, phosphor atoms were doped into the TiO x N y catalyst in this study. Phosphor doping has been utilized to reduce the size of PtRu nanoparticles,9 TiO2 photocatalysts,10 etc. and thus increase their surface area. The X-ray diffraction and Raman spectroscopy analyses revealed that crystal structure of the bulk was TiN and the surface was rutile TiO2 with oxygen vacancy. The effect of phosphor to titanium molar ratio on the ORR activity, stability and the reaction mechanism will be presented at the meeting. Acknowledgments The author acknowledges Dr Kohei Okitsu, Prof Hojun Im and Mr Yusei Tsushima for providing assistance in obtaining the X-ray photoelectron (XP) spectra, Raman spectra and microscopy images, respectively. This work was partially supported by a Grant-in-Aid for Scientific Research (C) (17K06180) from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan; a research grant from Nippon Sheet Glass Foundation for Materials Science and Engineering in Japan; a research grant from Yashima Environment Technology Foundation and a research grant from Suzuki Foundation in Japan. The XP spectra were acquired with the support by Nanotechnology Platform of the MEXT of Japan. References A. Ferrero, K. Preuss, A. Marinovic, A. B. Jorge, N. Mansor, D. J. L. Brett, A. B. Fuertes, M. Sevilla and Maria-M. Titirici, ACS Nano, 10, 5922 (2016).Li, Q. Gao, W. Qian, W. Tian, H. Zhang, Q. Zhang and Z. Liu, Sci. Rep., 8, 2863 (2018).Yoshida and K. Kojima, ECS Interface 24, 45 (2015).Parrondo, T. Han, E. Niangar, C. Wang, N. Dale, K. Adjemian and V. Ramani, Proc. Natl Acad. Sci., 111, 45 (2014).Chisaka, Y. Ando, Y. Yamamoto and N. Itagaki, Electrochim. Acta, 214, 165 (2016).Chisaka, Y. Yamamoto, N. Itagaki and Y. Hattori, ACS Appl. Energy Mater., 1, 211 (2018).Chisaka, A. Ishihara, H. Morioka, T. Nagai, S. Yin, Y. Ohgi, K. Matsuzawa, S. Mitsushima and K. Ota, ACS Omega, 2, 678 (2017).Chisaka, Y. Ando and N. Itagaki, J. Mater Chem. A, 4, 2501 (2016).Daimon and Y. Kurobe, Catal. Today, 111, 182 (2006).C. Yu, L. Zhang, Z. Zheng and J. Zhao, Chem. Mater., 15, 2280 (2003).

Highly efficient electrocatalyst of N-doped graphene-encapsulated cobalt-iron carbides towards oxygen reduction reaction

Development of highly functional and durable catalysts in a cost-effective way is a promising approach for practical energy conversion applications. In this study, a novel catalyst, cobalt iron carbide nanoparticles encapsulated by nitrogen doped graphene nanosheets, is successfully synthesized through a simple refluxing strategy followed by a post annealing process. It is found that the catalyst exhibits excellent catalytic activity for oxygen reduction reaction in alkaline medium. The oxygen reduction reaction kinetics of the catalyst mainly follow a 4-electron transferred pathway along with good diffusion limit current density, highly positive onset potential (−0.04 V) and half-wave potential (−0.11 V). In addition to catalytic activity, the catalyst demonstrates advanced superior stability, and excellent methanol tolerance in comparison with commercial platinum catalyst. The impressive catalytic performance of the catalyst is attributed to the unique mesoporous metal-core/graphene-shell architecture in which high interactions between two transition metals and transition metal-carbon synergistically provide enhanced catalytically active sites, accelerate interfacial charge transfer, and optimize oxygen adsorption energy. The results demonstrate that such catalyst can be an alternative low-cost and efficient catalyst for oxygen reduction reaction in energy conversion applications.

Enhanced electrocatalytic reduction of oxygen at CO2-derived Fe[sbnd]N[sbnd]B-doped porous carbon

FeNB doped carbon catalysts are synthesized directly from flue gas containing CO2. They showed enhanced activity for oxygen reduction reaction in an alkaline electrolyte (1 M NaOH), which is comparable activity of commercial platinum catalysts. The amorphous carbon contains nitrogen species derived from nitrogen gas in flue gas and boron atoms which were originated from the reducing agent of sodium borohydride for the flue gas conversion. The amounts of iron species was controlled from 5% to 55% of synthesized amorphous carbon from flue gas. The sample with 33% of Fe precursor species shows the highest oxygen reduction reaction activity. This is due to the existence of pyridinic nitrogen doping and FeN bonding in the carbon network verified by X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS) analyses. Also, from the microscopic images, the degradation of oxygen reduction reaction activity comes from agglomeration of Fe species. The FeNBC catalyst shows the promise of stability in acidic conditions and long-term durability for 10,000 cyclic voltammetric cycles.

TePtFe Nanotubes as High-Performing Bifunctional Electrocatalysts for the Oxygen Reduction Reaction and Hydrogen Evolution Reaction.

Currently, a multicomponent platinum-based alloy has been applied as a promising electrocatalyst to improve catalysis and lower the usage of the noble metal platinum. Herein, a tellurium nanowire (NW)-derived ternary TePtFe nanotube (NT) electrocatalyst has been prepared by the Kirkendall effect. The TePtFe NT formed consists of small single-crystal nanoparticles and voids with an open-end and hollow structure. The TePtFe NT electrocatalyst presents an impressive catalytic activity and stability for both the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). Its ORR specific activity and mass activity are 8.5 and 2.4 times, respectively, improved relative to those of commercial platinum catalysts. It is also impressive that, for the HER, a very low overpotential of 28.1 mV at 10 mA cm-2 can be achieved; this is lower than that of platinum (51.8 mV) catalysts in 0.1 m HClO4 , and the activity is improved, even after 5000 cycles. This work reveals that TePtFe NTs can be employed as nanocatalysts with an impressive catalytic activity and stability for application in fuel cells and hydrogen production.

Co9S8-porous carbon spheres as bifunctional electrocatalysts with high activity and stability for oxygen reduction and evolution reactions

The oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) of multi-electron transfer are footstone and crucial reactions for energy conversion and storage technologies. The catalysts play the important roles in both ORR and OER. It is particularly desirable but difficult to use cheap raw materials and facile way to prepare non-noble metal bifunctional electrocatalysts with high activity and stability for both ORR and OER. Here, a simple and effective method is reported for synthesizing cobalt sulfide (Co9S8)-porous carbon spheres composite catalyst (Co9S8/CS) with thiourea, glucose and cobalt nitrate. The material structures of N, S co-doped carbon combined with Co9S8 have been evidenced by high-resolution transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Under the thermal treatment temperature of 800 °C, the prepared catalyst exhibits an analogous oxygen reduction dynamics behavior to the commercial platinum catalyst with a four-electron pathway, and a superior oxygen evolution performance with the small reversible potential gap of 0.78 V (ΔE = Ej=10 – E1/2) to most of the bifunctional electrocatalysts reported to date, such as metal-free carbon hybrids and transition metal doped carbon materials. Due to the interaction between Co9S8 and N, S co-doping carbon, Co9S8/CS-800 exhibits exceptionally good durability and excellent activity compared with the commercial Pt/C for ORR and OER, predicting a promising application in metal-air batteries and fuel cells.

Unsupported Pt3Ni Aerogels as Corrosion Resistant PEFC Anode Catalysts under Gross Fuel Starvation Conditions

Mitigating catalyst corrosion is crucial for the commercial success of polymer electrolyte fuel cells (PEFCs). Novel catalysts that can withstand the harsh conditions in case of gross fuel (i.e. H2) starvation events at the PEFC anode are needed to increase the fuel cell stack's service life and to meet the durability targets set for automotive applications. To make progress in this respect, we have tested an unsupported, bimetallic Pt3Ni alloy (aerogel) catalyst at the PEFC anode and subjected it to a stress test that mimics the high potentials (≥ 1.5 V vs. the reversible hydrogen electrode) encountered upon fuel starvation. In contrast to commercial carbon-supported platinum catalysts (Pt/C), the Pt3Ni aerogel displays excellent durability and performance retention in end-of-life fuel cell polarization curves. Additionally, the aerogel catalyst shows ≈35% higher surface-specific activity for the hydrogen oxidation/evolution reaction than Pt/C. These results highlight the great potential of using novel unsupported catalysts at the anode of PEFCs.

Cu@C nanoporous composites containing little copper oxides derived from dimethyl imidazole modified MOF199 as electrocatalysts for hydrogen evolution reaction

It remains a huge challenge to develop non precious electrocatalysts with high activity to substitute commercial Pt catalysts for hydrogen evolution reactions (HER). Here, the C-Cu-DI and C-Cu materials with the copper based nanoporous carbon structures were synthesized by carbonizing MOF199 and DI-MOF199. The composite structure and HER electrocatalytic properties of the C-Cu-DI and C-Cu materials are studied. The results show that C-Cu-DI and C-Cu samples exhibit good catalytic activity. And C-Cu-DI sample through the addition of Dimethyl imidazole(DI) in the DI-MOF199 precursor has higher electrocatalytic activity than the C-Cu sample. The superior catalytic activity is attributed to the special composite structure of nanoscale deposition particles on the framework with plenty of nano pores and nano copper and few copper oxidation particles distributed or wrapped into the amorphous porous carbon phase. The nano copper and few copper oxidation particles in the C-Cu and C-Cu-DI catalysts maybe provide the more effective catalytic activity sites. The C-Cu-DI composite with large size spherical hollow deposition particles has higher conductivity, better BET surface area and reasonable micro-meso-macro porous distribution, so the overpotentials at the current density of 1mAcm−2 and 10mAcm−2 are respectively 270mV and 390mV vs. RHE. Although the HER activity has a big gap with commercial platinum catalyst, this study can provide an important experimental exploration for the design of copper based non noble metal/nano porous carbon composite HER electrocatalyst.

Towards industrial furfural conversion: Selectivity and stability of palladium and platinum catalysts under continuous flow regime

Furfural is an important biorefinery platform chemical, derived from hemicelluloses which represent an import fraction of lignocellulosic biomass feedstocks and waste streams originating from them. Recently, promising results have been reported on the hydrogenation of furfural, although the selectivity still may be improved. Most of these studies dealt with batch hydrogenation, however, hydrogenation in continuous flow is preferable for industrial applications. In this work, we compare the conversion, selectivity and stability on-stream in continuous flow regime of lab-synthesized and commercial palladium and platinum catalysts.

Nitrogen and sulfur co-doped mesoporous hollow carbon microspheres for highly efficient oxygen reduction electrocatalysts

Heteroatom-doped porous carbons are considered as one of the most promising metal-free electrocatalysts for highly efficient electrocatalytic reactions. Herein, nitrogen and sulfur co-doped mesoporous hollow carbon microspheres are fabricated using a feasible process involving the pyrolysis of polydopamine in the presence of sodium 1,5-naphthalenedisulfonate (1,5-NDSNa) and the use of mesoporous silica SBA-15 as hard template. The resultant carbon microspheres have a well-developed hierarchical porosity with large surface area, showing high-efficiency electrochemical oxygen reduction activity in alkaline media, along with much enhanced stability and methanol tolerance, as compared with those of commercial platinum catalysts. The superior electrocatalytic performance and stability of the catalyst might be due to the synergistic effect between N and S elements and the well-defined meso- and macroporosity, presenting great potential in the fields of fuel cells and metal-air batteries.