Activity For Methanol Oxidation Reaction Research Articles

Platinum/Tantalum Carbide Core–Shell Nanoparticles with Sub‐Monolayer Shells for Methanol and Oxygen Electrocatalysis

AbstractCore–shell architectures provide great opportunities to improve catalytic activity, but achieving nanoparticle stability under electrochemical cycling remains challenging. Herein, core–shell nanoparticles comprising atomically thin Pt shells over earth‐abundant TaC cores are synthesized and used as highly durable electrocatalysts for the methanol oxidation reaction (MOR) and the oxygen reduction reaction (ORR) needed to drive direct methanol fuel cells (DMFCs). Characterization data show that a thin oxidic passivation layer protects the TaC core from undergoing dissolution in the fuel cell‐relevant potential range, enabling the use of partially covered Pt/TaC core–shell nanoparticles for MOR and ORR with high stability and enhanced catalytic performance. Specifically, at the anode the surface‐oxidized TaC further enhances MOR activity compared to conventional Pt nanoparticles. At the cathode, the Pt/TaC catalyst feature increases tolerance to methanol crossover. These results show unique synergistic advantages of the core–shell particles and open opportunities to tailor catalytic properties for electrocatalytic reactions.

Rapid one-step aqueous synthesis of porous PtAg wavy nanochains for methanol electrooxidation with a high CO-tolerance

Tailored morphology of porous binary Pt-based nanostructures is a powerful way to improve their catalytic properties. Herein, we develop a facile aqueous solution approach for the rational one-step synthesis of PtAg nanochains via direct nucleation followed by the oriented attachment growth mechanism under sonication at room temperature. This allows the green and simple fabrication of PtAg wavy nanochains (200 nm length and 20 nm width) with spatially interconnected pores (10 nm) and a high surface area (55.02 m2/g). These merits endowed the methanol oxidation reaction (MOR) performance of PtAg nanochains with a mass activity of (1.12 mA/µgPt) that was about 1.83, 2.8, and 3.11 times higher than those of PtAg nanodendrites, Pt nanodendrites, and commercial Pt/C, respectively, owing to porous nanochain morphology and alloying effect. Intriguingly, visible-light irradiation enhances the MOR performance of PtAg nanochain by nearly 1.5 times, owing to its great photoelectric response properties. The MOR activity of PtAg nanochains is among the highest reported Pt-based electrocatalysts. The presented method may open new edges on the rational design of porous Pt-based nanoarchitecture for various catalytic applications.

Cascaded p-d Orbital Hybridization Interaction in Ultrathin High-Entropy Alloy Nanowires Boosts Complete Non-CO Pathway of Methanol Oxidation Reaction.

Designing high efficiency platinum (Pt)-based catalysts for methanol oxidation reaction (MOR) with high "non-CO" pathway selectivity is strongly desired and remains a grand challenge. Herein, PtRuNiCoFeGaPbW HEA ultrathin nanowires (HEA-8 UNWs) are synthesized, featuring unique cascaded p-d orbital hybridization interaction by inducing dual p-block metals (Ga and Pb). In comparison with Pt/C, HEA-8 UNWs exhibit 15.0- and 4.2-times promotion of specific and mass activity for MOR. More importantly, electrochemical in situ FITR spectroscopy reveals that the production/adsorption of CO (CO*) intermediate is effectively avoided on HEA-8 UNWs, leading to the complete "non-CO" pathway for MOR. Theoretical calculations demonstrate the optimized electronic structure of HEA-8 UNWs can facilitates a lower energy barrier for the "non-CO" pathway in the MOR.

Laser-Synthesized Co-Doped CuO Electrocatalyst: Unveiling Boosted Methanol Oxidation Kinetics for Enhanced Hydrogen Production Efficiency by In Situ/Operando Raman and Theoretical Analyses.

The present study details the strategic development of Co-doped CuO nanostructures via sophisticated and expedited pulsed laser ablation in liquids (PLAL) technique. Subsequently, these structures are employed as potent electrocatalysts for the anodic methanol oxidation reaction (MOR), offering an alternative to the sluggish oxygen evolution reaction (OER). Electrochemical assessments indicate that the Co-CuO catalyst exhibits exceptional MOR activity, requiring a reduced potential of 1.42V at 10 mAcm-2 compared to that of pure CuO catalyst (1.57V at 10 mAcm-2). Impressively, the Co-CuO catalyst achieved a nearly 180mV potential reduction in MOR compared to its OER performance (1.60V at 10 mA cm-2). Furthermore, when pairing Co-CuO(+)ǀǀPt/C(-) in methanol electrolysis, the cell voltage required is only 1.51V at 10 mAcm-2, maintaining remarkable stability over 12h. This represents a substantial voltage reduction of ≈160mV relative to conventional water electrolysis (1.67V at 10 mAcm-2). Additionally, both in situ/operando Raman spectroscopy studies and theoretical calculations have confirmed that Co-doping plays a crucial role in enhancing the activity of the Co-CuO catalyst. This research introduces a novel synthetic approach for fabricating high-efficiency electrocatalysts for large-scale hydrogen production while co-synthesizing value-added formic acid.

Research on preparation of high activity and durable carbon-supported platinum catalyst for methanol electro-oxidation by a facile continuous microwave pipeline method

In methanol oxidation reaction (MOR), it is crucial for the catalyst that Pt particles uniformly cover the surface of the carrier and the Pt surface active sites can effectively remove the binding with CO. This article develops a simple and effective continuous microwave technology. Carbon loaded nano platinum was synthesized by rapidly and uniformly heating a ethylene glycol mixture containing carbon black (CB) H2PtCl6 using microwave radiation, with a Pt content of 49.5%. The experimental results indicate that platinum particles are uniformly loaded onto the carbon surface, with uniform shape and size, and an average particle size of 3.02 nm. And the Pt/C catalyst prepared by continuous microwave technology showed enhanced electrocatalytic activity (peak current density of 76.95 mA/cm2) in MOR after heating at appropriate temperature in N2 atmosphere, which exceeded the commercial catalyst TKK (47.07 mA/cm2) by 63.6%. And the catalyst's resistance to CO toxicity and durability; Higher than commercial Pt/C catalysts. Compared with traditional methods, continuous microwave technology exhibits higher energy utilization efficiency and faster reaction speed in the catalyst preparation process. This technology also has the ability to achieve continuous preparation, which is one of the effective technological approaches to achieve large-scale catalysts production.

Oxygen Vacancies Alter Methanol Oxidation Pathways on NiOOH.

A thorough comprehension of the mechanism underlying the methanol oxidation reaction (MOR) on Ni-based catalysts is critical for future electrocatalytic design and development. However, the mechanism of MOR on these materials remains a matter of controversy. Herein, we combine in situ surface-enhanced infrared absorption spectroscopy (SEIRAS) and density functional theory (DFT) calculations to identify the active sites and determine the mechanism of MOR on monometallic Ni-based catalysts in alkaline media. The SEIRAS results show that formate and (bi)carbonate are formed after the commencement of the MOR with potential-dependent relative distributions. These spectroscopic results are in good agreement with the DFT-computed reaction profiles over an oxygen vacancy, suggesting that the MOR mainly proceeds through the formate-involving pathway, in which the early consumption of methanol yields formate as the major product, while increasing potential drives further oxidation of formate to (bi)carbonate. We also find a parallel pathway for the generation of (bi)carbonate at high potentials that bypasses the formation of formate. The two main pathways are thermodynamically more feasible than the one predominantly reported in the literature for MOR on NiOOH that involves CHO and/or CO as key intermediates. These DFT results are supported by spectroscopic evidence showing that no band associated with CHO or CO can be detected by SEIRAS, which is attributed to the nature of the oxygen vacancies as the active sites, suppressing deep dehydrogenation of CH2O to CHO. This work thus shows the promising role of defect engineering in promoting the electrocatalytic MOR activity and selectivity.

TiO2 Nanolayer–Coated Carbon as Pt Support for Enhanced Methanol Oxidation Reaction

Abstract To facilitate the large-scale application of direct methanol fuel cells (DMFCs), the issue of low Pt/C durability due to Pt degradation and carbon corrosion in harsh DMFC operating conditions must be addressed. A promising strategy is to hybridize metal oxides with carbon materials, resulting in a durable and conductive support that exhibits a strong metal-support interaction (SMSI) effect on platinum nanoparticles (Pt NPs). In this study, we introduced a TiO2 coating on carbon black, creating a TiO2 nanolayer between Pt and carbon black. The nanolayer not only protects the carbon black but also activates the SMSI effect on Pt. The resulting Pt/C@TiO2 electrocatalyst exhibits superior durability than commercial Pt/C. After the accelerated durability test, the mass activity loss of the methanol oxidation reaction (MOR) of Pt/C@TiO2 (32%) is significantly lower than that of Pt/C (46.8%). Moreover, the MOR activity of Pt/C@TiO2 is higher than Pt/C as well. It suggests that Pt/C@TiO2 shows great potential as a highly durable and active electrocatalyst for DMFCs.

Ruthenium-doped Ni(OH)2 to enhance the activity of methanol oxidation reaction and promote the efficiency of hydrogen production.

The coupling of the hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR) to produce clean hydrogen energy with value-added chemicals has attracted substantial attention. However, achieving high selectivity for formate production in the MOR and high faradaic efficiency for H2 evolution remain significant challenges. In light of this, this study constructs an Ru/Ni(OH)2/NF catalyst on nickel foam (NF) and evaluates its electrochemical performance in the MOR and HER under alkaline conditions. The results indicate that the synergistic effect of Ni(OH)2 and Ru can promote the catalytic activity. At an overpotential of only 42 mV, the current density for the HER reaches 10 mA cm-2. Moreover, in a KOH solution containing 1 M methanol, a potential of only 1.36 V vs. RHE is required to achieve an MOR current density of 10 mA cm-2. Using Ru/Ni(OH)2/NF as a bifunctional catalyst, employed as both the anode and cathode, an MOR-coupled HER electrolysis cell can achieve a current density of 10 mA cm-2 with a voltage of only 1.45 V. Importantly, the faradaic efficiency (FE) for the hydrogen production at the cathode and formate (HCOO-) production at the anode approaches 100%. Therefore, this study holds significant practical implications for the development of methanol electro-oxidation for formate-coupled water electrolysis hydrogen production technology.

CuNi sulphidation maximizes MOR activity by expanding the accessibility of active sites!

Sulphidation of a CuNi alloy of Cu : Ni ratio 81 : 19 led to an exponential activity enhancement in the alkaline methanol oxidation reaction (MOR) by four fold due to an order of magnitude increase in the number of active Cu and Ni sites and improved charge transfer properties.

In Situ Pt Migration Enabled Resurrection of Electrocatalyst and Fuel Cell Device.

In direct methanol fuel cells (DMFCs), the poisoning of noble metals is considered to be a major impediment to their commercial development. Here, it is found that the loss of surface Pt is one main reason for the attenuation of catalyst performance during long-time methanol oxidation reaction (MOR). A strategy to realize in situ resurrection of the deactivated catalyst by migrating Pt atoms inside to the surface is innovatively proposed. A high-activity Pt-SnO2 is designed, whose MOR activity is resurrected to 97.4% of the initial value. Based on this, the multiple resurrection of a DMFC device is also achieved for the first time. This work provides a new approach for the solution of catalyst deactivation and the development of sustainable catalysts as well as fuel cells.

The Trade-Off Relationship between Particle Proximity Effect and Low-Pt Loading to Optimize Oxygen Reduction and Methanol Oxidation Reaction Activity

Pt-based electrocatalysts have long been considered as the most effective oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) catalysts due to their excellent intrinsic activity. For supported catalysts, Pt loading, particle size, interparticle distance (ipd), and interaction with support are identified as key contributors for high activity and selectivity. The proximity effect is a relatively new topic in catalysis research. There is a contradiction between the traditional view which induces the electronic interaction to reduce the activity and the new view which causes the electrical double-layer overlap of adjacent nanoclusters, changes the potential distribution and improves the specific activity. [1, 2]To this end, we have developed the nitrogen-doped graphite-like carbon sheets supporting low-Pt loading (Pt@N-GC) with uniform sizes and controllable ipd, and disentangled the main effect of ipd on ORR activity/selectivity and MOR activity/CO tolerance. Combining electrochemical tests and the trade-off mechanism between proximity effect and low-Pt loading, the following trends were obtained:1) 10.0 wt% Pt@N-GC with highest Pt loading and lowest ipd inhibits 2e- ORR by strong adsorption and reabsorption of *OOH due to the presence of closer Pt sites, and improves 4e- ORR selectivity. However, the mass activity/specific activity reached the maximum under the optimal low-Pt loading of 5.0 wt%.2) Similarly, 10.0 wt% Pt@N-GC weakened the adsorption of the -OH group of oxidized COads intermediates, led to the strong adsorption of COads on the catalyst surface, inactivated of Pt sites and reduced the CO resistance. Considering the need to improve CO tolerance while increasing MOR activity, the 5.0 wt% low-Pt loading catalyst exhibiting the best MOR performance under the optimal ipd.3) Benefiting by the synergistic effect of Pt nanoparticles and N-GC support, all Pt@N-GCs exhibit bifunctional electrocatalytic activity and durability.We attribute these findings to the underlying mechanism trade-off between the particle proximity effect and low-Pt loading under the uniform particle size and controlled ipd (Figure. 1). We believe the proximity effect has positive and negative effects, how to maximize the advantages of proximity effect can provide valuable guidance for the design and optimization of low-Pt loading bifunctional electrocatalysts in the future.[1] M. Nesselberger, M. Roefzaad, R.F. Hamou, P.U. Biedermann, F.F. Schweinberger, S. Kunz, K. Schloegl, G.K. Wiberg, S. Ashton, U. Heiz, K.J. Mayrhofer, M. Arenz, Nat. Mater., 12 (2013) 919-924.[2] M. Watanabe, H. Sei, P. Stonehart, J. Eelectroanal. Chem., 261 (1989) 375-387. Figure 1. The trade-off mechanism analysis between proximity effect and low-Pt loading. Figure 1

Mixed-Dimensional Partial Dealloyed PtCuBi/C as High-Performance Electrocatalysts for Methanol Oxidation with Enhanced CO Tolerance.

Developing efficient electrocatalysts for methanol oxidation reaction (MOR) is crucial in advancing the commercialization of direct methanol fuel cells (DMFCs). Herein, carbon-supported 0D/2D PtCuBi/C (0D/2D PtCuBi/C) catalysts are fabricated through a solvothermal method, followed by a partial electrochemical dealloying process to form a novel mixed-dimensional electrochemically dealloyed PtCuBi/C (0D/2D D-PtCuBi/C) catalysts. Benefiting from distinctive mixed-dimensional structure and composition, the as-obtained 0D/2D D-PtCuBi/C catalysts possess abundant accessible active sites. The introduction of Cu as a water-activating element weakens the COads, and oxophilic metal Bi facilitates the OHads, thereby enhancing its tolerance to CO poisoning and promoting MOR activity. The X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure spectroscopy (XAFS) collectively reveal the electron transfer from Cu and Bi to Pt, the electron-enrichment effect induced by dealloying, and the strong interactions among Pt-M (Cu, Pt, and Bi) multi-active sites, which improve the tuning of the electronic structure and enhancement of electron transfer ability. Impressively, the optimized 0D/2D D-PtCuBi/C catalysts exhibit the superior mass activity (MA) of 17.68 A mgPt -1 for MOR, which is 14.86 times higher than that of commercial Pt/C. This study offers a proposed strategy for Pt-based alloy catalysts, enabling their use as efficient anodic materials in fuel cell applications.

Design and catalytic performance of Cu/γ-Al2O3 for electrocatalytic methanol oxidation reaction by using density functional theory and molecular dynamics

The electrocatalytic activity of methanol oxidation reaction (MOR) on Cu/γ-Al2O3 and the growth behavior of Cu on γ-Al2O3 are investigated by using density functional theory and molecular dynamics. It is found that the interaction between the Cu3 cluster and γ-Al2O3(110) is stronger than that between the Cu4 cluster and γ-Al2O3(110). Consequently, the d-band center of the Cu3 cluster locates close to the Fermi level compared to the d-band center of the Cu4 cluster, resulting in high electrocatalytic MOR activity on Cu3/γ-Al2O3(110). The electrocatalytic MOR pathway is non-CO pathway on Cu3/γ-Al2O3(110). The highest Gibbs free energy pathway is CH3O* → CH2O*, which the Gibbs free energy is 0.53 eV. To achieve a high proportion of 2D Cu cluster on γ-Al2O3, it is recommended to prepare the catalyst at temperatures below 500 K with Cu loading below 21.78 wt%. These findings provide valuable insights into the design of MOR catalysts.

Electronic structure engineering of Pt3Co nanoparticles via B, N co-doping of the carbon support boosts electrocatalytic methanol oxidation

Developing highly efficient and durable catalysts for the methanol oxidation reaction (MOR) is crucial to the commercialization and widespread uptake of direct methanol fuel cells (DMFCs). Carbon-supported Pt nanoparticle (NP) catalysts demonstrate high initial activities for MOR, but suffer from electrochemical instability. Herein, nanoalloying and heteroatom-doping strategies were adopted to prepare well-ordered intermetallic Pt3Co NPs anchored on B, N co-doped multiwalled carbon nanotubes, with the developed Pt3Co/BN-MWCNTs electrocatalyst offering high stability for MOR in 0.1 M HClO4. Benefiting from the optimal electronic structure of the ordered Pt3Co NPs and asymmetric electron transfer (B → C → N) in the support, the activity, stability and CO poisoning resistance of Pt3Co/BN-MWCNTs electrocatalyst were significantly enhanced compared to a commercial Pt/C catalyst. Density functional theory (DFT) calculations revealed that electronegativity differences between Pt and Co enable significant charge redistribution, lowering the energy barriers and potentials for the oxidation of the *CO intermediate by OH* species, greatly enhancing MOR kinetics under acid conditions. Further, B, N co-doping of the MWCNTs strengthened the interaction with the Pt3Co NPs, further boosting MOR performance by suppressing Pt3Co dissolution into the electrolyte. The findings of this work are expected to be applied in catalyst design for a wide range of energy conversion devices.

Enhanced Hydroxyl Adsorption in Ultrathin NiO/Cr2 O3 In-Plane Heterostructures for Efficient Alkaline Methanol Oxidation Reaction.

The exploration of advanced nickel-based electrocatalysts for alkaline methanol oxidation reaction (MOR) holds immense promise for value-added organic products coupled with hydrogen production, but still remain challenging. Herein, we construct ultrathin NiO/Cr2 O3 in-plane heterostructures to promote the alkaline MOR process. Experimental and theoretical studies reveal that NiO/Cr2 O3 in-plane heterostructures enable a favorable upshift of the d-band center and enhanced adsorption of hydroxyl species, leading to accelerated generation of active NiO(OH)ads species. Furthermore, ultrathin in-plane heterostructures endow the catalyst with good charge transfer ability and adsorption behavior of methanol molecules onto catalytic sites, contributing to the improvement of alkaline MOR kinetics. As a result, ultrathin NiO/Cr2 O3 in-plane heterostructures exhibit a remarkable MOR activity with a high current density of 221 mA cm-2 at 0.6 V vs Ag/AgCl, which is 7.1-fold larger than that of pure NiO nanosheets and comparable with other highly active catalysts reported so far. This work provides an effectual strategy to optimize the activity of nickel-based catalysts and highlights the dominate efficacy of ultrathin in-plane heterostructures in alkaline MOR.

Hybrid Acid/Base Electrolytic Cell for Hydrogen Generation and Methanol Conversion Implemented by Bifunctional Ni/MoN Nanorod Electrocatalyst.

Combining the methanol oxidation reaction (MOR) and hydrogen evolution reaction (HER) within an integrated electrolytic system may offer the advantages of enhanced kinetics of the anode, reduced energy consumption, and the production of high-purity hydrogen. Herein, it is reported the construction of Ni─MoN nanorod arrays supported on a nickel foam substrate (Ni─MoN/NF) as a bifunctional electrocatalyst for electrocatalytic hydrogen production and selective methanol oxidation to formate. Remarkably, The optimal Ni─MoN/NF catalyst displays exceptional HER performance with an overpotential of only 49mV to attain 10mAcm-2 in acid, and exhibits a high activity for MOR to achieve 100mAcm-2 at 1.48V in alkali. A hybrid acid/base electrolytic cell with Ni─MoN/NF electrode as anode and cathode is further developed for an integrated HER-MOR cell, which only requires a voltage of 0.56V at 10mAcm-2 , significantly lower than that of the HER-OER system (0.70V). The density functional theory studies reveal that the incorporation of Ni effectively modulates the electronic structure of MoN, thereby resulting in enhanced catalytic activity. The unique combination of high electrocatalytic activity and excellent stability make the Ni─MoN/NF catalyst a promising candidate for practical applications in electrocatalytic hydrogen production and methanol oxidation.

Enlightening the performance-boosting effect of electroactivation approaches on the electrooxidation of methanol reaction in acidic media catalyzed by cobalt-tin bimetallic nanocatalysts

This research investigates the impact of electrochemical activation on cobalt-tin (Cox-Sn100-x) bimetallic nanocatalysts for the methanol oxidation reaction (MOR) in acidic conditions. Two electroactivation protocols, namely activation in a phosphate buffer (PB) solution and in-situ activation, using chronoamperometry, were developed. The electrochemical performance of the MOR electrocatalyst was evaluated through cyclic voltammetry analysis within a specific electrode potential range. Optimal activation conditions for the PB solution were achieved at a pH of 3.0 and an activation potential of −1.3 V (vs. Ag/AgCl), while the in-situ activation process showed the best results at an activation potential of −0.7 V (vs. Ag/AgCl). Both the in-situ and PB electroactivated Co65–Sn35 catalysts exhibited significant enhancements in MOR activity, with the in-situ activation resulting in a 10-fold increase and the PB activation leading to an 8.5-fold increase. The proposed mechanism for this substantial enhancement involves simultaneous hydrogen evolution and water electrolysis during the electroactivation treatments of the Co65–Sn35 electrocatalyst. In fact, the formation of OHads species during the electroactivation treatment could provide a fraction of OHads which was essential for the MOR. These findings might present opportunities for the engineering and design of bimetallic noble metal-free nanocatalysts for efficient utilization in high-performance acidic direct methanol fuel cells (DMFCs).

Precision tuning of highly efficient Pt-based ternary alloys on nitrogen-doped multi-wall carbon nanotubes for methanol oxidation reaction

The electrochemical methanol oxidation is a crucial reaction in the conversion of renewable energy. To enable the widespread adoption of direct methanol fuel cells (DMFCs), it is essential to create and engineer catalysts that are both highly effective and robust for conducting the methanol oxidation reaction (MOR). In this work, trimetallic PtCoRu electrocatalysts on nitrogen-doped carbon and multi-wall carbon nanotubes (PtCoRu@NC/MWCNTs) were prepared through a two-pot synthetic strategy. The acceleration of CO oxidation to CO2 and the blocking of CO reduction on adjacent Pt active sites were attributed to the crucial role played by cobalt atoms in the as-prepared electrocatalysts. The precise control of Co atoms loading was achieved through precursor stoichiometry. Various physicochemical techniques were employed to analyze the morphology, element composition, and electronic state of the catalyst. Electrochemical investigations and theoretical calculations confirmed that the Pt1Co3Ru1@NC/MWCNTs exhibit excellent electrocatalytic performance and durability for the process of MOR. The enhanced MOR activity can be attributed to the synergistic effect between the multiple elements resulting from precisely controlled Co loading content on surface of the electrocatalyst, which facilitates efficient charge transfer. This interaction between the multiple components also modifies the electronic structures of active sites, thereby promoting the conversion of intermediates and accelerating the MOR process. Thus, achieving precise control over Co loading in PtCoRu@NC/MWCNTs would enable the development of high-performance catalysts for DMFCs.

Ultra-Small Ceria Nanocrystals at Carbon Surface Synthesized by Ultrasound Sonication: A Study of Highly Active Platinum-Cerium Bifunctional Catalysts for Methanol Oxidation and Oxygen Reduction

ABSTRACT Cerium (IV) oxide (called ceria) has gained a lot of interest from researchers due to its high oxygen storage capacity (1) and high tolerance toward CO-like intermediates of methanol oxidation reaction (MOR) (2,3). In our previous study (4), the ceria crystals were synthesized by the modified solvothermal synthesis with urea (5) and grain size of ceria was around 30 µm, even if the crystallite size was only 11 nm. However, even this huge grain-size CeOx particles contributed insignificantly to the catalytic synergetic effect of ceria at the PtCe catalysts toward MOR.The parameters influencing the deposition of Pt nanoparticles (NPs) on the ceria-carbon support by the ethylene glycol (EG) reduction method were investigated in previous study (4). It was found that the influence of energy supply methods on the reaction system needs to be simplified to control the nucleation and growth of Pt NPs better.Although the role of catalytically active components (Pt and CeOx) in catalyst is important, the structure of carbon support affects the catalytic behaviour of the catalyst significantly. The chromium carbide-derived carbon, noted as C(Cr-CDC), synthesized in our previous study (6) is active materials toward oxygen reduction reaction in 0.1 mol dm─3 KOH due to its high number of the active sites at the surface, large specific surface area, and unique micro-mesoporous structure. Therefore, it is a good support material for this study.The purpose of this study was to synthesize a ceria with small grain size, improve the activity of Pt NPs synthesized by tuning the parameters of EG reduction method, and compare the activity of the novel PtCe/C(Cr-CDC) materials and PtCe/C (commercial Ketjenblack carbon) materials.In detail, the ceria-carbon materials were synthesized firstly by ultrasound sonication method in the mixture of EG and sodium hydroxide solutions, called sonochemical method. Later, the Pt NPs were deposited onto the ceria-carbon materials by EG reduction method using the refluxing system. All the materials were characterized with thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy with energy dispersive X-ray (SEM-EDX) methods. All the PtCe/C materials were measured in the 3-electrode system in 0.5 mol dm─3 H2SO4 and in a mixture of 0.5 mol dm─3 H2SO4 + 1 mol dm─3 CH3OH to investigate the electrochemical behaviour and MOR activity, respectively.The results of XRD and SEM-EDX revealed that it was possible to synthesize the ultra-small ceria NPs by the sonochemical method. The crystallite size is smaller than 2 nm. EDX confirmed the presence of cerium in measuring areas, however, the grain size of ceria in ceria-carbon was too small to be revealed with SEM. The TGA confirmed that all cerium was deposited onto carbon with approximately 11 wt. % of the total ceria-carbon weight. Besides, XRD and TGA also confirmed the success of Pt deposition method. The electrochemical activity at PtCe/C materials revealed high electrochemically active surface area value (55-80 mPt 2 gPt −1). ACKNOWLEDGEMENT This work was supported by the EU through the European Regional Development Fund TK141 “Advanced materials and high-technology devices for energy recuperation systems” (2014-2020.4.01.15-0011) and Personal Research Grant PRG676. The SEM-EDX measurements were conducted using the NAMUR+ core facility funded by the Estonian Research Council (TT 13). REFERENCES E. Antolini and J. Perez, Int. J. Hydrog. Energy, 36, 15752–15765 (2011).S. Dai, J. Zhang, Y. Fu, and W. Li, New J. Chem., 42, 18159–18165 (2018).D. Y. Chung, K.-J. Lee, and Y.-E. Sung, J. Phys. Chem. C, 120, 9028–9035 (2016).H. Q. V. Nguyen, J. Nerut, H. Kasuk, M. Härmas, P. Valk, T. Romann, M. Koppel, P. Teppor, J. Aruväli, O. Korjus, O. Volobujeva, and E. Lust, J. Solid State Electrochem. (2022).S. B. Atla, M.-N. Wu, W. Pan, Y. T. Hsiao, A.-C. Sun, M.-J. Tseng, Y.-J. Chen, and C.-Y. Chen, Mater. Charact., 98, 202–208 (2014).H. Q. V. Nguyen, J. Nerut, H. Kasuk, V. Grozovski, T. Thomberg, I. Tallo, R. Palm, M. Koppel, T. Romann, R. Härmas, J. Aruväli, M. Külaviir, and E. Lust, Russ. J. Electrochem., 58, 781–797 (2022).

Enhanced Methanol Oxidation Using Polymer-Incorporated Ultra Rough Pt Electrodes

We report on the methanol oxidation reaction (MOR) on very rough Pt surfaces. Numerous previous studies show that the cyclic voltammetry of MOR on Pt exhibits hysteretic behavior due to Pt oxide poisoning during the anodic scan at higher potentials. Only after the Pt oxide is removed during the cathodic scan is the Pt surface reactivated and MOR activity resumed (Fig. 1). We developed an electrodeposition method yielding Pt electrodes with high roughness factors (Rf > 80) controlled by varying deposition time. These rough electrodes exhibit linear MOR without hysteresis (Fig. 1), indicating the rougher Pt surface is resistant to poisoning during MOR up to potentials of 1.4 V vs. RHE. The effect is found in either acidic or basic electrolyte. Further studies show the roughness effect is related effective increase in the surface concentration of methanol and effective decrease in the surface concentration of water. The lower water activity inhibits Pt surface oxidation and facilitates methanol oxidation. Treatments to artificially decrease surface water concentration have a similar effect. This study provides methods to increase the rate of organic molecule oxidation at electrode surfaces and is relevant to both electro synthesis and direct methanol fuel cell applications. Figure 1