Platinum decorated mesoporous titanium cobalt nitride nanorods catalyst with promising activity and CO-tolerance for methanol oxidation reaction

In this study, mesoporous titanium cobalt nitride nanorods (Ti_0.9Co_0.1N NRs) hybrid as non-carbon platinum supports is successfully prepared by a solvothermal process and subsequent nitridation process. The highly porous materials can provide abundant binding sites for growing well-dispersed Pt. The X-ray photoelectron spectroscopy results indicate that the cobalt element doping promoted the interaction of platinum and support. Notable, the peak current density of Pt/Ti_0.9Co_0.1N NRs catalyst is 0.85 A mgpt^?1, which 3.4-fold of Pt/C catalyst. What's more, the onset potential (0.34 V) of CO oxidation on Pt/Ti_0.9Co_0.1N NRs is lower than on the Pt/C (0.47 V) and Pt/TiN NRs (0.37 V). The results confirmed the mesoporous Pt/Ti_0.9Co_0.1N NRs catalyst unfolds a much enhanced catalytic activity and CO tolerance for methanol oxidation. The exceptional electrocatalytic properties are achieved for the Pt/Ti_0.9Co_0.1N NRs catalysts due to its unique porous structure and the electronic effect of robust Ti_0.9Co_0.1N NRs introduced by the cobalt element doping.     

High conductivity of novel Ti0.9Ir0.1O2 support for Pt as a promising catalyst for low-temperature fuel cell applications

The novel nanostructured Ti_0.9Ir_0.1O₂ acting as a potential catalyst support for Pt in fuel cell applications was easily synthesized by means of a facile and simple low-temperature hydrothermal process without using any surfactants and further heat treatment. Interestingly, even in low iridium doping concentration, the Ti_0.9Ir_0.1O₂ support possessed the high electronic conductivity of 0.016 S/cm, which was ∼10⁵ times as high as pure TiO₂ (4.15 × 10⁻⁷ S/cm), suggesting the efficient doping of iridium into TiO₂ lattice. Furthermore, the modified chemical reduction route utilized to prepare the 20 wt % Pt/Ti_0.9Ir_0.1O₂ electrocatalyst exhibited the good anchoring and uniform distribution of Pt nanoparticles (NPs) (∼3 nm) over Ti_0.9Ir_0.1O₂ surface and thus eventually resulted in the high electrochemical surface area (∼85.08 m²/gPt) compared to that of the commercial 20 wt % Pt/C (E-TEK) catalyst (∼69.21 m²/gPt). The cyclic voltammetry results in the methanol media revealed that the 20 wt % Pt/Ti_0.9Ir_0.1O₂ displayed the superior electrocatalytic activity compared to the 20 wt % Pt/C (E-TEK) catalyst towards the methanol electro-oxidation. For instance, the 20 wt % Pt/Ti_0.9Ir_0.1O₂ catalyst possessed the higher oxidation current density (∼28.8 mA/cm²), the lower onset potential (∼0.12 V) and the higher I_f/I_b ratio in comparison with the commercial 20 wt % Pt/C (E-TEK) catalysts. It is worth noting that the chronoamperometry results also indicated that the 20 wt % Pt/Ti_0.9Ir_0.1O₂ exhibited higher durability than the commercial 20 wt % Pt/C (E-TEK) catalyst. Beside introducing novel Ti_0.9Ir_0.1O₂ material, these results also offer a pathway of exploring the low dopants content of Ti_xIr_1-xO₂ material to serve as a good catalyst support for many fuel cell applications.     

Electrooxidation of ethanol and glycerol on carbon supported PtCu nanoparticles

Four carbon supported PtCu nanostructured catalysts with Pt:Cu atomic ratios of 1:3.20, 1:2.23, 1:0.61 and 1:0.35 were synthesized by a two-step route, involving the chemical reduction of Cu ions on the carbon support, followed by the partial galvanic replacement of Cu atoms by Pt. Bimetallic nanostructured particles with average sizes in the range of 2.3–3.2 nm were obtained. The bimetallic catalysts with surface Pt contents between 20 and 55 at. % were formed by a Cu-rich core surrounded by a Pt-Cu shell, while that with the highest Pt content presented a uniform alloy structure instead of a core-shell arrangement. The electrocatalytic performance of the as-prepared materials toward ethanol electrooxidation in acid and alkaline media and glycerol oxidation in alkaline environment was investigated by cyclic voltammetry and chronoamperometry. It was observed that the electrocatalytic activity of PtCu nanoparticles was found to depend on the surface composition, platinum utilization efficiency, structure and Pt ensemble. Among the as-prepared catalysts, Pt_0·62Cu_0·38/C core-shell material showed the best performance for ethanol oxidation in both acid and alkaline environments, while Pt_0·24Cu_0·76/C and Pt_0·31Cu_0·69/C core-shell catalysts exhibited the highest activity for glycerol oxidation in alkaline medium. The electrochemical results showed that the catalytic activity of the bimetallic Cu@PtCu core-shell nanostructured nanoparticles is between four and ten times higher than that of a commercial Pt_0·51Ru_0·49/C catalyst.     

Platinum supported on hydroxyl-grafted poly (3,4-ethylenedioxythiophene)-modified RuCo,N-tridoped bamboo-like carbon nanotubes for direct methanol fuel cell

The development of highly active and efficient heterogeneous catalytic oxidation system has become an attractive research field. In this paper, a catalyst (RuCo/N-CNT@PEDOT-OH/Pt) from platinum nanoparticles (Pt NPs) supported on hydroxyl-grafted poly(3,4-ethylenedioxythiophene) (PEDOT–OH)-modified RuCo, N-tridoped bamboo-like carbon nanotubes (RuCo/N-CNT) are used for direct methanol fuel cell (DMFC). The electrocatalytic activity of RuCo/N-CNT@PEDOT-OH/Pt is systematically compared with RuCo/N-CNT/Pt (Pt NPs supported on RuCo/N-CNT without PEDOT-OH) in the methanol oxidation reaction (MOR). The growth mechanism of carbon nanotubes and the role of heteroatom doping in the electrocatalytic process is explored. The catalysts show excellent electrocatalytic performance with high stability for MOR. It is found that the mass activity (MA) of the RuCo/N-CNT@PEDOT-OH/Pt (1961.3 mA mg^?1_Pt) for MOR was higher than that of RuCo/N-CNT/Pt (1470.1 mA mg^?1_Pt) and the commercial Pt/C catalysts (281.0 mA mg^?1_Pt), indicating the positive effect of the PEDOT-OH in the electrocatalytic MOR. In addition, density functional theory (DFT) calculations verify the possible mechanism pathways of the obtained RuCo/N-CNT@PEDOT-OH/Pt catalyst. This presented catalyst offers new inspiration for designing efficient electrocatalysts for methanol oxidation.     

Enhanced Electro-catalytic Activity of Nitrogen-doped Reduced Graphene Oxide Supported PdCu Nanoparticles for Formic Acid Electro-oxidation

Successful commercialization of direct formic acid fuel cells (DFAFCs) is restricted because of its apparent instability in acidic medium and high cost of typically noble metal based anode catalyst. To adequately address these key issues, in this work, a series of palladium-copper alloy catalyst supported on nitrogen-doped reduced graphene oxide (N-rGO) were synthesized via wet chemical reduction process. Several microscopic and spectroscopic techniques were employed to determine the crystal pattern, particle size, composition and morphology of the synthesized material. Electro-catalytic performance of the synthesized catalysts was carefully verified with respect to formic acid oxidation. All N-doped reduced graphene oxide (N-rGO) supported catalyst show enhanced catalytic activity in comparison to commercial Pd/C catalyst. Electrochemical study reveals precisely that Pd₇₅Cu₂₅/N-rGO catalysts have highest electro catalytic activity 1738 mA mg⁻¹_pd among all synthesized catalyst which is 3.67 times higher than commercial Pd/C catalyst. Pd₇₅Cu₂₅/N-rGO catalyst show lowest Tafel slope (119 mV dec⁻¹) and excellent stability after 250 potential cycles. These extensive studies signify that N-rGO support material can remarkably improve the catalytic activity and stability of the catalysts which may be due to outstanding electron transfer capability and synergy between PdCu metallic and N-rGO support. This work helps further design of alloy nanoparticles on N-rGO support as a highly active and stable catalyst for application in the fuel cell.     

Electrochemically synthesized Cu/Pt core-shell catalysts on a porous carbon electrode for polymer electrolyte membrane fuel cells

A novel two-step method has been developed to efficiently prepare Cu/Pt core-shell structured catalysts for the first time. The Cu is first electrodeposited on the surface of the porous carbon electrode (PCE) and the deposited Cu is then partially replaced by Pt spontaneously. The addition of the thiourea (TU) along with the pH adjustment can tremendously reduce the self-dissolution of Cu due to dissolved oxygen. The results show that Cu/Pt core-shell structured catalysts display very good activities even at very low Pt loadings. The peak power density of a single cell using Cu/Pt core-shell structured catalysts is over 0.9 W cm⁻² at Pt loadings as low as 0.24 mg cm⁻² on each cathode and anode. This study shows that it is possible to apply this method for fabrication various core-shell structured functional materials.     

Composite‐supported Pt catalyst and electrosprayed cathode catalyst layer for polymer electrolyte membrane fuel cell

A major limitation of the conventional polymer electrolyte membrane fuel cell (PEMFC) catalysts is the fast oxidative degradation of their carbon black supports. Complete replacement of carbon black is difficult because of its low‐cost and high electrical conductivity. Reported here are the development and optimization of composite‐supported Pt catalysts and the electrosprayed cathode catalyst layer with these catalysts for PEMFC. These catalysts are supported by a composite of carbon black (Vulcan XC‐72R) and the electrochemically much more stable carbon‐embedded niobium‐doped titanium dioxide nanofibers (C/Nb_0.1Ti_0.9O₂). Four different catalyst supports with 20 wt.% Pt were prepared by air spraying and electrospraying to compare their activity and stability. Vulcan XC‐72R and C/Nb_0.1Ti_0.9O₂ were tested as pristine support materials for comparison as well as 1:3 and 3:1 mixtures by weight of the two pristine support materials (composite supports). The amount of Nafion in the catalyst ink was optimized for each catalyst layer by a volumetric method. An increase in carbon black content of the support layer from 0% to 100% increases the performance of these catalysts in H₂/air PEMFCs but also increases the loss of oxygen reduction reaction mass activity. The best balance between PEMFC performance and durability was obtained for the Pt catalyst with 25% carbon black in the support layer, while the highest initial oxygen reduction reaction mass activity was obtained for the catalyst with 75% carbon black content. Copyright © 2017 John Wiley & Sons, Ltd.     

Pt nanoparticles supported on titanium iron nitride nanotubes prepared as a superior electrocatalysts for methanol electrooxidation

Titanium iron nitride (Ti_0.95Fe_0.05N) supports with one-dimensional (1D) hollow and porous nanotubes(Ti_0.95Fe_0.05N NTs)are prepared by a two-step method, including hydrothermal method followed post-nitriding treatment. Pt nanoparticles (NPs) are further supported on Ti_0.95Fe_0.05N NTs for methanol electrooxidation. The experimental results reveal that the prepared material is Ti_0.95Fe_0.05N NTs with high purity, and this support is characterized by a porous tubular structure with hollow walls and large specific surface area. The X-ray photoelectron spectroscopy (XPS) pattern shows the strong interaction between the robust Ti_0.95Fe_0.05N NTs support and uniform Pt NPs catalyst. In addition, the electrochemical data demonstrate that Ti_0.95Fe_0.05N NTs loaded Pt NPs (Pt/Ti_0.95Fe_0.05N) display greatly improved activity and stability than that of Pt/C catalyst. The significantly enhanced durability of the hybrid electrocatalysts and electrochemical surface area (ECSA) preservation of the catalyst are observed after the accelerated durability test (ADT). The experimental data verify that the introducing of Fe can tune the electronic structure of Pt atoms, which contributes to the strengthened activity and stability of the Pt catalyst for the methanol oxidation reaction.     

Facile fabrication and electrocatalytic activity of Pt0.9Pd0.1 alloy film catalysts

A nano-thickness porous Pt_0.9Pd_0.1 alloy film with a greatly enhanced surface area were firstly synthesized at a glassy carbon electrode (GCE) using a facile cyclic voltammetry (CV) method. The atomic ratio of the alloy can be controlled by controlling the composition of the electrodeposition solution. We found that small amount of alloying Pd is an excellent catalytically enhancing agent for the Pt catalyst, and 10% Pd is the optimal. The structures of the Pt_0.9Pd_0.1 alloy film were characterized by FE-SEM, XPS, XRD and electrochemical techniques. It was found that the Pt_0.9Pd_0.1 film was in nanoporous structure and consisted of crystallites of 10.1 nm on average, leading to the modified electrode (Pt_0.9Pd_0.1/GCE) has an effective surface area as large as 790 times that of a corresponding bare Pt disk electrode. The Pt_0.9Pd_0.1/GCE exhibited significantly higher stability and catalytic activity for both of the methanol electro-oxidation reaction (MOR) and the oxygen electro-reduction reaction (ORR) than the correspondingly electrodeposited Pt modified GCE. The advantage can be attributed to the CV-prepared nano-porous structure on the electrode surface. This method and the prepared electrode can be expected to have promising applications in biosensors and fuel cells, etc.     

Mechanism of heteroatom-doped Cu5 catalysis for hydrogen evolution reaction

Developing high-performance hydrogen evolution reaction (HER) electrocatalysts is of great significance for solving the global energy crisis. Cluster has great application potential in the field of catalysis due to their unique quantum size effect and high specific surface area. Herein, the HER catalytic performance of Cu₅ cluster were regulated and optimized by doping heteroatoms. The Gibbs free energy calculation shows that the catalytic activity of Cu₅Ni and Cu₅Pt is comparable to that of Pt-based catalysts, and the Gibbs free energy value of Cu₅C can even reach 0.005 eV, indicating its much higher catalytic performance than that of other catalysts. Thus, the catalytic activity of Cu₅ clusters is optimized by doping non-metal and transition metal atoms to regulate the geometric and electronic structure of Cu₅. It was found that Cu₅Ni, Cu₅Pt and Cu₅C are potential catalysts to replace Pt-based catalysts for reducing the cost and achieving large-scale hydrogen production. This work provides a new avenue to regulate the catalytic performance of clusters, which is helpful for the further development and application of clusters in the field of catalysis.     

Lattice-strained Pt nanoparticles anchored on petroleum vacuum residue derived N-doped porous carbon as highly active and durable cathode catalysts for PEMFCs

High cost and poor durability of Pt-based cathode catalysts for oxygen reduction reaction (ORR) severely hamper the popularization of proton exchange membrane fuel cells (PEMFCs). Tailoring carbon support is one of effective strategies for improving the performance of Pt-based catalysts. Herein, petroleum vacuum residue was used as carbon source, and nitrogen-doped porous carbon (N-PPC) was synthesized using a simple template-assisted and secondary calcination method. Small Pt nanoparticles (Pt NPs) with an average particles size of 1.8 nm were in-situ prepared and spread evenly on the N-PPC. Interestingly, the lattice compression (1.08%) of Pt NPs on the N-PPC (Pt/N-PPC) was clearly observed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), which was also verified by the shift of (111) crystal plane of Pt on N-PPC to higher angles. The X-ray photoelectron spectroscopy (XPS) results suggest that the N-PPC support had a strong effect on anchoring Pt NPs and endowing surface Pt NPs with lowered d band center. Thus, the Pt/N-PPC as a catalyst simultaneously boosted the ORR activity and durability. The specific activity (SA) and mass activity (MA) of the Pt/N-PPC at 0.9 V reached 0.83 mA cm⁻² and 0.37 A mg_Pt⁻¹, respectively, much higher than those of the commercial Pt/C (0.21 mA cm⁻² and 0.11 A mg_Pt⁻¹) in 0.1 M HClO₄. The half-wave potential (E_1/2) of Pt/N-PPC exhibited only a minimal negative shift of 7 mV after 30,000 accelerated durability tests (ADT) cycles. More importantly, an H₂–O₂ fuel cell with a Pt/N-PPC cathode achieved a power density of 866 mW cm⁻², demonstrating that the prepared catalyst has a promising application potential in working environment of PEMFCs.     

ZrO2 anchored core-shell Pt–Co alloy particles through direct pyrolysis of mixed Pt–Co–Zr salts for improving activity and durability in proton exchange membrane fuel cells

Highly active and durable Pt-based catalysts for oxygen reduction reaction (ORR) are very important and necessary for the proton exchange membrane fuel cells (PEMFCs). In this paper, we report the preparation and performance study of ORR catalysts composed of core-shell Pt–Co alloy nanoparticles (NPs) on multi-walled carbon nanotubes (MWCNTs) anchored with ZrO₂ NPs (denoted as Pt–Co–ZrO₂/MWCNTs). Thanks to the unique three-phase structure, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR at 0.9 V versus reversible hydrogen electrode (RHE) is1577 mA mg_Pt^?1, which is ～6.6-fold higher than that of the commercial Pt/C (238 mA mg_Pt^?1). After 50,000 cycles for durability test, the mass activity of Pt–Co–ZrO₂/MWCNTs for ORR remained 88% of its initial value. In stark contrast, that of Pt/C kept only about 56.3% of its initial value. More importantly, its catalytic performance was fully observed/verified in a H₂-air PEMFC single cell test. When the Pt loading of Pt–Co–ZrO₂/MWCNTs loaded cathode was one fourth of that with commercial Pt/C as the cathode catalyst, comparable cell performance was achieved. More impressively, the MEA with Pt–Co–ZrO₂/MWCNTs underwent only 24.5% degradation in maximum power density after 30,000 accelerated durability tests (ADTs). However, the MEA with Pt/C after 30,000 ADTs exhibited 39.6% performance loss in maximum power density. The enhanced mass activity and catalytic durability of Pt–Co–ZrO₂/MWCNTs could be attributed to the core-shell Pt–Co alloy NPs with Pt-rich surface and the interface effect between Pt–Co alloy NPs and oxygen vacancy-rich ZrO₂ NPs. In addition, this research also provided a solution to the durability issue of cathodes without sacrificing ORR mass activity, which would promote practical application of PEMFCs.     

Properties of Pt-based electrocatalysts containing selectively deposited Sn as the anode for polymer electrolyte membrane fuel cells

Sn-promoted Pt-based catalysts were prepared by the chemical vapor deposition (CVD) of Sn on commercial Pt/C and PtRu/C catalysts using Sn(CH₃)₄ as an Sn precursor. The prepared catalysts showed higher CO tolerance than those prepared by adding Sn using an impregnation (IMP) method. This result was obtained because Sn added by CVD was selectively deposited on the Pt and Ru surfaces, instead of on a carbon support, such that the interfacial contact between Pt and Sn was greater in the Sn-CVD catalyst than in the others, as confirmed by in-situ infrared and X-ray photoelectron spectroscopic observations of the catalysts.     

Synthesis and characterization the multifunctional nanostructures TixW1-xO2 (x = 0.5; 0.6; 0.7; 0.8) supports as robust non-carbon support for Pt nanoparticles for direct ethanol fuel cells

In the present study, various mesoporous Ti_xW_1-xO₂ (x = 0.5; 0.6; 0.7; 0.8) supports were fabricated via a facile solvothermal approach and explored the effect of doping tungsten concentration on electrochemical properties of Ti_xW_1-xO₂-supported Pt electrocatalysts toward ethanol electrochemical reaction. Interestingly, the incorporation of tungsten into TiO₂ lattices with the doping tungsten amounts (20 and 30 at %) resulted in boosting both the surface area and electrical conductivity, however, a reverse trend was observed when increasing the doped tungsten content more than 40 at %. Additionally, the relatively well-distributed Pt nanoparticles with the small particle size (ca. 3 nm) anchored on supports were achieved using a microwave-assisted polyol route. Electrochemical results indicated that various Ti_xW_1-xO₂-supported Pt catalysts exhibited the catalytic performance greater than that of the commercial carbon-supported Pt (E-TEK) catalyst for ethanol electro-oxidation reaction (EOR). For as-obtained electrocatalysts, the Ti_0.7W_0.3O₂-supported Pt catalyst showed the highest mass activity (~260.23 mA/mg_Pt) and greatest I_f/I_b ratio (~1.34), which ~2.0-fold and ~1.57-time higher than that of carbon-supported Pt (E-TEK) catalyst (~130.62 mA/mg_Pt for mass activity and ~0.85 for I_f/I_b ratio, respectively). After 5000 cycling tests, the mass activity loss of Ti_xW_1-xO₂-supported Pt catalysts was around twice lower than that of the commercial Pt/C (E-TEK) catalysts, suggesting that the Ti_xW_1-xO₂-supported Pt catalysts exhibited the superior stability toward ethanol electrochemical oxidation. The outstanding electrochemical activity and stability of Ti_xW_1-xO₂-supported Pt electrocatalysts were owing to the synergetic effect between Pt nanocatalyst and non-carbon Ti_xW_1-xO₂ supports as well as superior natural durability of TiO₂-based materials.     

Synthesis and characterization of Pt on novel catalyst supports for the H2 production in the Westinghouse cycle

This work shows the preparation and physicochemical and electrochemical characterization of Pt based catalysts supported on two different catalyst supports (Vulcan carbon and SiC/TiC) with a 40 wt% Pt content for the depolarized SO₂ electro-oxidation in the hybrid sulfur process, which is a promising approach for the hydrogen production. The Pt based catalysts supported on carbon showed the lowest Pt crystallite size, but the electrochemical surface area of the Pt deposited on the Si_0.9CTi_0.1C was the highest of the three catalysts prepared in the lab under the same operation conditions. The Pt catalysts supported on the novel SiC/TiC based material are promising catalysts for this technology as they showed high catalyst activity and durability in sulfuric acid conditions.     

Electrochemical synthesis and characterization of carbon-supported Pt and Pt–Ru nanoparticles with Cu cores for CO and methanol oxidation in polymer electrolyte fuel cells

Pt and Pt–Ru shells on Cu cores supported on Vulcan carbon XC72R have been synthesized and tested as possible anode electrocatalysts for polymer electrolyte fuel cells. Pt(Cu)/C was prepared by Cu electrodeposition on the black carbon support at constant potential followed by Pt deposition on Cu by galvanic exchange, whereas Pt–Ru(Cu)/C was prepared by spontaneous deposition of Ru species on Pt(Cu)/C. The corresponding cyclic voltammograms in 0.5 M H₂SO₄ solution showed the hydrogen adsorption/desorption peaks and no Cu oxidation. The respective CO stripping peak potentials of Pt(Cu)/C and Pt–Ru(Cu)/C were about 0.1 and 0.2 V more negative than those corresponding to Pt/C and Ru-decorated Pt/C. The best conditions for CO oxidation were found for Cu deposition potentials between −0.2 and −0.4 V vs. Ag/AgCl/KCl(sat). The Pt economy of the Pt–Ru(Cu)/C system was proved for the methanol oxidation, with specific currents more than twice those obtained on the Ru-decorated commercial Pt/C catalysts.     

Synthesis and characterisation of platinum–cobalt–manganese ternary alloy catalysts supported on carbon nanofibers: An alternative catalyst for hydrogen evolution reaction

A systematic method for obtaining a novel electrode structure based on PtCoMn ternary alloy catalyst supported on graphitic carbon nanofibers (CNF) for hydrogen evolution reaction (HER) in acidic media is proposed. Ternary alloy nanoparticles (Co0.6Mn0.4 Pt), with a mean crystallite diameter under 10 nm, were electrodeposited onto a graphitic support material using a two-step pulsed deposition technique. Initially, a surface functionalisation of the carbon nanofibers is performed with the aid of oxygen plasma. Subsequently, a short galvanostatic pulse electrodeposition technique is applied. It has been demonstrated that, if pulsing current is employed, compositionally controlled PtCoMn catalysts can be achieved. Variations of metal concentration ratios in the electrolyte and main deposition parameters, such as current density and pulse shape, led to electrodes with relevant catalytic activity towards HER. The samples were further characterised using several physico-chemical methods to reveal their morphology, structure, chemical and electrochemical properties. X-ray diffraction confirms the PtCoMn alloy formation on the graphitic support and energy dispersive X-ray spectroscopy highlights the presence of the three metallic components from the alloy structure. The preliminary tests regarding the electrocatalytic activity of the developed electrodes display promising results compared to commercial Pt/C catalysts. The PtCoMn/CNF electrode exhibits a decrease in hydrogen evolution overpotential of about 250 mV at 40 mA cm⁻² in acidic solution (0.5 M H₂SO₄) when compared to similar platinum based electrodes (Pt/CNF) and a Tafel slope of around 120 mV dec⁻¹, indicating that HER takes place under the Volmer-Heyrovsky mechanism.     

Pt catalyst supported on titanium suboxide for formic acid electrooxidation reaction

Pt catalysts supported on titanium suboxide (Ti₄O₇), commercial TiO₂ and carbon black were prepared by a borohydride reduction method, respectively, and used as electrocatalysts for direct formic acid fuel cells (DFAFCs). Transmission electron microscopy (TEM) images show that Pt nanoparticles have a poorer dispersion on Ti₄O₇ compared to that on TiO₂ and carbon black due to the hydrophobicity and high density of Ti₄O₇. Nevertheless, according to cyclic voltammetry (CV) and chronoamperometry (CA) results, it is found that the Pt/Ti₄O₇ catalyst possesses better catalytic activity and stability. Besides the high electrical conductivity, it is suggested from X-ray photoelectron spectroscopy (XPS) analyses that the higher content of metallic Pt caused by the Ti₄O₇ support material also contributes to the better catalytic performance of Pt/Ti₄O₇.     

Cost-effective Co3O4 nanospheres on nitrogen-doped graphene used as highly efficient catalyst for oxygen reduction reaction

Developing low-cost, efficient and stable catalyst for the oxygen reduction reaction is meaningful and necessary for the industrialization of fuel cells. In this work, we report the controllable synthesis of Co₃O₄ nanospheres uniformly anchored on N-doped reduced graphene oxide (N-rGO) sheets with significant catalytic activity for the oxygen reduction reaction via a simple two-step approach. Results show that there is an interaction between Co₃O₄ nanospheres and N-rGO after riveting on N-rGO, which is beneficial to the electron transfer between them. The Co₃O₄ NS/N-rGO hybrid has excellent catalytic activity, comparable to commercial Pt/C catalyst. The transferred electron number of the oxygen reduction reaction on Co₃O₄ NS/N-rGO is around 3.95. The hybrid has more excellent durability and methanol resistance than commercial Pt/C. The Co₃O₄ NS/N-rGO catalyst in our work provides a cost-effective the oxygen reduction reaction catalyst alternative to the precious metal Pt in fuel cell.     

Methanol,ethanol and ethylene glycol electro-oxidation at Pt and Pt–Ru catalysts electrodeposited over oxidized carbon nanotubes

Pt and Pt–Ru catalysts supported on oxidized multi-walled carbon nanotubes with different ruthenium content ranging from 19 to 30 at.% were prepared by pulse electrodeposition and tested for methanol, ethanol and ethylene glycol oxidation in H₂SO₄ electrolyte. The catalysts were mainly composed by small 3D irregular-shaped agglomerates of nano-sized particles.