Electrocatalytic Oxidation Reaction Research Articles

0D/2D Co3O4/Ti3C2 MXene Composite: A Dual-Functional Electrocatalyst for Energy-Saving Hydrogen Production and Urea Oxidation

Electrocatalytic water splitting to produce hydrogen (H2) is a sustainable way of meeting energy demands at no environmental cost. However, the sluggish anodic reaction imposes a considerable overpotential requirement. By contrast, the electrocatalytic urea oxidation reaction offers the prospect of energy-saving H2 production together with urea-rich wastewater purification. In this work, a 0D/2D Co3O4/Ti3C2 MXene composite was synthesized by a simple solution reaction approach under mild conditions and applied as an efficient and stable electrocatalyst for hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) in basic medium (1 M KOH+0.5 M urea). The Co3O4/Ti3C2 MXene electrodes delivered a current density of 10 mA cm–2 at an overpotential of 124 mV for HER and required 1.40 V to reach 10 mA cm–2 for UOR. The hybrid catalyst could maintain high activity after 40 h continuous catalytic reaction for both UOR and HER. Its catalytic performance was significantly improved compared to that of pure Ti3C2 MXene and Co3O4 solving the problem of insufficient exposure of active sites caused by too large particle size and agglomeration of Co3O4 particles. Notably, Co3O4/Ti3C2 MXene was applied as a bifunctional catalyst for overall urea-containing water splitting, and showed certain energy saving advantages compared with other reported Co-based catalysts. This work provides a strategy for application other than noble metal-based electrode materials for urea-containing wastewater purification coupled with H2 production.

Laccase mediated electrosynthesis of heliotropin on mango-kernel derived carbon nanosphere composite: A sustainable approach

Facile fabrication of enzyme immobilized carbon nanospheres (CNS) based catalysts with high electrical conductivity and catalytic efficiency are of decisive importance for their electrocatalysis. Herein, we report a novel, green and highly efficient synthesis route for the development of an electrode surface with enhanced electrical conductivity and better catalytic activity for the electrochemical synthesis of heliotropin. An important organic intermediate, heliotropin is widely employed in organic synthetic chemistry, perfume, pharmaceutical and dye industries. To design an efficient electrocatalyst, the obtained biowaste (mango seed kernels) was pyrolyzed and subjected to acid treatment to form functionalised CNS (f-CNS). The functionalised CFP electrode was employed as a template for laccase immobilization. This was further treated with free laccase resulting in the formation of Lac-fCNS/CFP electrode. The enzyme based catalytic effect of the developed electrode exhibited excellent electrooxidation of piperonyl alcohol in the presence of TEMPO, which served as the mediator. A high yield (72%) of heliotropin was achieved during the electrooxidation at 0.78 V via bulk electrolysis. The obtained product (heliotropin aka piperonal) was confirmed via 1 H NMR and 13 C NMR. Additionally, computational molecular docking analysis of f-CNS:laccase composite showed strong binding affinity (-6.2 kcal/mol) with TEMPO in comparison with free laccase (-5.1 kcal/mol). The excellent selectivity and efficiency of the developed electrocatalyst aims to surpass all other reported laccase-TEMPO mediated based electrocatalytic oxidation reactions. Effect of porosity obtained from carbon nanospheres might be the reason for the present investigations. • Facile synthesis of mango-seed kernel derived carbon nanospheres (CNS) via pyrolysis. • Laccase immobilization onto functionalized CNS, an effective carbon substrate for electrochemical synthesis. • Laccase-TEMPO mediated electrochemical oxidation of piperonyl alcohol to form heliotropin or piperonal. • A higher binding affinity observed in the interactions between the fabricated composite (Lac-fCNS) and TEMPO was studied by Molecular docking analysis.

Plasmon-Enhanced C-C Bond Cleavage toward Efficient Ethanol Electrooxidation.

Ethanol, as a sustainable biomass fuel, is endowed with the merits of theoretically high energy density and environmental friendliness yet suffers from sluggish kinetics and low selectivity toward the desired complete electrooxidation (C1 pathway). Here, the localized surface plasmon resonance (LSPR) effect is explored as a manipulating knob to boost electrocatalytic ethanol oxidation reaction in alkaline media under ambient conditions by appropriate visible light. Under illumination, Au@Pt nanoparticles with plasmonic core and active shell exhibit concurrently higher activity (from 2.30 to 4.05 A mgPt-1 at 0.8 V vs RHE) and C1 selectivity (from 9 to 38% at 0.8 V). In situ attenuated total reflection-surface enhanced infrared absorption spectroscopy (ATR-SEIRAS) provides a molecular level insight into the LSPR promoted C-C bond cleavage and the subsequent CO oxidation. This work not only extends the methodology hyphenating plasmonic electrocatalysis and in situ surface IR spectroscopy but also presents a promising approach for tuning complex reaction pathways.

Microwave-assisted growth of spherical core-shell NiFe LDH@CuxO nanostructures for electrocatalytic water oxidation reaction

The high energy demand for electrochemical water splitting arises from sluggish oxygen evolution reaction (OER) kinetics. In this regard, Layered double hydroxide (LDH) has been introduced as an outstanding catalyst for the OER due to its exceptional physiochemical and 2D infrastructure properties. Herein, we report the design and synthesiss of core-shell nanostructured electrocatalyst by rationally decorating vertically oriented NiFe LDH ultrathin nanosheets on CuxO support (NiFe LDH@CuxO) via microwave-assisted hydrothermal reaction. For OER, the NiFe LDH@CuxO core-shell nanostructured catalyst demonstrated promising electrocatalytic performance, requiring only 1.43 V onset potential and 270 mV overpotential at 10 mA cm−2. The NiFe LDH@CuxO also outperformed pristine NiFe LDH and iridium oxide (IrO2) in terms of electrocatalytic activity, durability, and Faradaic efficiency. The fabricated NiFe-LDH@CuxO electrocatalyst with outer shell NiFe-LDH ultrathin nanosheets provides numerous exposed active sites, benefits electrolyte diffusion and oxygen gas releasing and also reduces the interfacial charge transfer resistance to enhance OER activity. Furthermore, exclusive core-shell 3D infra-structure effectively prevents NiFe-LDH nanosheets agglomeration and restacking, enhancing electrochemical stability.

High-performance methanol electrolysis towards energy-saving hydrogen production: Using Cu2O-Cu decorated Ni2P nanoarray as bifunctional monolithic catalyst

Electrocatalytic methanol oxidation reaction (MOR) is a promising alternative approach to oxygen evolution reaction for efficient hydrogen production. However, developing highly efficient and cost-effective MOR catalysts, coupled with the cathodic hydrogen evolution reaction, is still a challenge. Herein, we used a Ni2P nanosheet array with Cu2O-Cu dendrites on nickel foam (Cu2O-Cu@Ni2P/NF) as an efficient and stable electrocatalyst for MOR, which attained a low potential of 1.41 V at 100 mA cm−2 and a small Tafel slope of 44.99 mV dec–1 with excellent stability for at least 24 h in 1.0 M KOH solution with 1.0 M methanol. In situ Raman spectroscopy reveals that Cu2O-Cu promotes the generation of the β-NiOOH active phase, and converts to Cu(II)O under the electrolysis conditions. Furthermore, the methanol electrolysis cell utilizing Cu2O-Cu@Ni2P/NF as both the cathode and anode delivered a current density of 10 mA cm−2 at a low cell voltage of 1.40 V, and the cell voltage decreased by 210 mV at a current density of 100 mA cm−2 compared to water electrolysis. This work provides a new strategy to design the promising Ni-based phosphide as a bifunctional electrocatalyst in methanol electrolysis, enabling energy-saving H2 production.

Au(111) Surface Oxidation Kinetics Probed by Electrocatalytic Oxidation of Formic Acid

The kinetics of surface oxidation for Au(111) in 0.1 M HCOOH + 0.1 M HClO4 was studied at 20 °C utilizing the electrocatalytic formic acid oxidation reaction (FAOR). In the surface oxidation region, cyclic voltammetry shows a distinct dependence of FAOR on scan rate revealing simultaneous deactivation of active surface sites. The surface oxide is essentially inactive for the FAOR. A series of current-time curves was recorded after potential steps into the potential range between 0.65 and 1.00 V vs saturated Mercury-mercurous sulfate electrode and analyzed within a three-step surface oxidation model, which successively involves (i) adsorption at surface defects, (ii) adsorption on well-defined Au(111) terraces, and (iii) two-dimensional nucleation-and-growth on terraces. Although Au surface oxidation is by far more complex, the system can be described in terms of the intrinsic activity of the Au(111) surface and the oxide coverage The chronoamperometric measurements can be modeled without considering the interaction of the oxide species with the FAOR and the co-adsorption of anions. The potential dependence of the kinetic parameters is used to obtain theoretical current-time curves for FAOR on Au(111). This study sheds light on the “fast FAOR” and contributes to the understanding of degradation phenomena in electrocatalysis.

Nickel-Doped Carbon Dots as an Efficient and Stable Electrocatalyst for Urea Oxidation.

Urea is a typical contaminant present in wastewater which may cause severe environmental problems. Electrochemical catalytic oxidation of urea has emerged as an efficient approach to solve this problem. Nevertheless, the current nickel-based catalysts (e.g., nickel hydroxide/sulfides) feature a high metal content. It not only lowers the utilization efficiency of nickel but also causes secondary pollution to the environment. Here, nickel-doped carbon dots (Ni-CDs) with an excellent and stable catalytic activity for the electrocatalytic urea oxidation reaction (UOR) are reported. Specifically, carbon dots (CDs) with abundant functional groups are synthesized by a one-pot hydrothermal method and then Ni-CDs with a very low metal content (1.1 at%) are prepared. The Ni2+ sites by coordination with carboxylic groups on the CDs provide excellent electrocatalytic activity and excellent durability for the UOR, as demonstrated by an anodic current density of 100mA cm-2 at a potential of 1.38V (vs RHE) and similar experimental results in practical application. To the best of knowledge, this is the first report of CDs-based materials applied for the UOR, which opens an important new area of applicability for CDs as well as broadens the scope of the materials for electrochemical catalysis of urea.

A Janus heteroatom-doped carbon electrocatalyst for hydrazine oxidation.

The trade-off between the intrinsic activity and electronic conductivity of carbon materials is a major barrier for electrocatalysis. We report a Janus-type carbon material combining electrically conductive nitrogen-doped carbon (NC) and catalytically active boron, nitrogen co-doped carbon (BNC). The integration of NC with BNC can not only ensure high electronic conductivity of the hybrid, but also achieve an enhancement in the intrinsic activity of the BNC side due to the electron redistribution on their coupling interfaces. In the electrocatalytic hydrazine oxidation reaction (HzOR), the Janus carbon electrocatalyst exhibits superior activity than their single counterparts and simple physical mixtures. Density functional theory calculations reveal that the NC/BNC interfaces simultaneously promote efficient electron transport and decrease the free energy of the rate-determining step in the HzOR process.

Favorable Electrocatalytic Ammonia Oxidation Reaction Thermodynamics on the β-NiOOH(0001) Surface Computed by Density Functional Theory

Favorable Electrocatalytic Ammonia Oxidation Reaction Thermodynamics on the β-NiOOH(0001) Surface Computed by Density Functional Theory

Stabilizing efficient structures of superwetting electrocatalysts for enhanced urea oxidation reactions

Layered hydroxides have shown superior catalytic activity for the electrocatalytic organic compound oxidation reaction. However, metal leaching can lead to uncontrollable structural phase transformation. Here, we report a Cr-Ni(OH) 2 electrocatalyst as a model of a pre-catalyst for the identification of the structure-performance relationship. The optimized electrocatalyst delivered superb performances, i.e., a low potential of 1.38 V (versus reversible hydrogen electrode [RHE]) to reach 100 mA cm −2 and stable activity over 200 h at 10 mA cm −2 . In situ analyses and theoretical calculations demonstrate that well-tuned electronic structures and the superhydrophilic-superaerophobic surface can enable rapid urea oxidation reaction (UOR) kinetics, which reduces the specific adsorption OH − and significantly depresses Cr dopants leaching, and this helps to maintain high UOR performance. Furthermore, the crucial role of mass transfer improvement to alleviate the structural decay under high potentials is disclosed. • Catalyst with suitable wettability and optimized electronic structures was achieved • Rapid UOR kinetics significantly suppress Cr leaching • The improvement in mass transfer is crucial in stabilizing efficient structures The electrocatalytic organic compound oxidation reaction has been extensively employed to replace water electro-oxidation. However, most of their electrocatalysts suffer from sluggish kinetics with a large overpotential, further resulting in uncontrollable structural reconstruction of the catalyst. Here, a Cr-Ni(OH) 2 electrocatalyst with well-controlled superhydrophilicity-superaerophobicity was developed as a model to understand the structural stability of metal hydroxides during alkaline urea oxidation reaction (UOR). The rapid UOR kinetics of the Cr-Ni(OH) 2 electrocatalysts can ensure the high stability of efficient structures, resulting in best-in-class performances. Importantly, the discovery of structure and phase transformation at high potentials due to mass transfer limits created optimal electrocatalyst conditions for Cr-Ni(OH) 2 to promote urea-assisted hydrogen production, which is generally ignored by the field. A robust structure of electrocatalysts is critical for achieving a highly efficient urea oxidation reaction. Here, we demonstrate the regulation of electronic structures and the superwetting property of electrocatalysts in obtaining rapid UOR kinetics. Corroborated with in situ spectrum studies and theoretical calculations, rapid UOR kinetics can significantly suppress Cr dopants leaching, and mass transfer improvement plays a key role in stabilizing efficient structures at high potential.

Boosting SO2 electrocatalytic oxidation reaction on highly dispersed subnanometric Au/TiO2 catalyst

The increase in the consumption of fossil fuels led not only to the increase of atmospheric CO2 level, but also to the increment in sulfur pollutants production, such as SO2. The electrochemical SO2 oxidation reaction (SO2OR) was already shown to be efficiently catalyzed by Au and, to further develop the technological knowledge in this field, the application of nanostructured Au catalysts is highly desirable. Herein we present a highly dispersed subnanometric Au/TiO2 catalyst as active material for SO2OR. The Tafel analysis revealed a change in the reaction mechanism and a substantial increase of the electrocatalytic reaction activity compared to bulk Au, even at conditions where bulk Au presented low activity, such as H2SO4 electrolyte. Electrochemical impedance spectroscopy (EIS) results led to the conclusion that TiO2 is also involved in the reaction, since not only the oxide time constant changes with the applied potential but also adsorbed intermediates were observed. This EIS response is probably related to the Au/TiO2 interface, which reflects on the oxide time constant.

Self-supported Mo-doped TiO2 electrode for ambient electrocatalytic nitrogen oxidation

Electrocatalytic nitrogen oxidation reaction (NOR) provides an eco-friendly pathway for ambient N2 fixation and nitrate/nitric acid synthesis but is plagued by sluggish kinetics due to the weak adsorption of N2 molecules and cleavage of NN triple bonds. Herein, a self-supported Mo-doped TiO2 electrode prepared by one-step hydrothermal method is reported for efficient nitrogen oxidation. Electrochemical measurements and spectroscopy investigations reveal that the inert TiO2 is effectively triggered by Mo substitution in terms of enhanced N2 adsorption and activation. As further confirmed by density function theory calculations, the incorporation of Mo reduces the barrier of the rate-determining step and provides an energetically favorable NOR pathway compared to pristine rutile TiO2. Electrochemical results show that Mo-doped TiO2 electrode achieves a nitrate yield of 5.44 μg h−1 mgcat−1 (or 8.77 ± 0.39 nmol h−1 cm−2) with a Faradaic efficiency of 2.88%. The formation of nitrate from N2 under positive bias is further demonstrated by in situ ultraviolet-visible spectrophotometry. This work provides experimental and theoretical evidences that Mo doping can stimulate the stable yet electrocatalytically inert Ti-based oxide toward NOR via promoting active sites formation and lowering activation energy barriers.

Trends and progress in application of cobalt-based materials in catalytic, electrocatalytic, photocatalytic, and photoelectrocatalytic water splitting.

There has been a growing interest in water oxidation in recent two decades. Along with that, remarkable discovery of formation of a mysterious catalyst layer upon application of an anodic potential of 1.13V vs. standard hydrogen electrode (SHE) to an inert indium tin oxide electrode immersed in phosphate buffer containing Co(II) ions by Nocera et.al, has greatly attracted researchers interest. These researches have oriented in two directions; one focuses on obtaining better understanding of the reported mysterious catalyst layer, further modification, and improved performance, and the second approach is about designing coordination complexes of cobalt and investigating their properties toward the application in water splitting. Although there have been critical debates on true catalysts that are responsible for water oxidation in homogeneous systems of coordination complexes of cobalt, and the case is not totally closed, in this short review, our focus will be mainly on recent major progress and developments in the design and the application of cobalt oxide-based materials in catalytic, electrocatalytic, photocatalytic, and photoelectrocatalytic water oxidation reaction, which have been reported since pioneering report of Nocera in 2008 (Kanan Matthew and Nocera Daniel in Science 321:1072-1075, 2008).

One-Pot Synthesis of Pt Nanobowls Assembled from Ultrafine Nanoparticles for Methanol Oxidation Reaction.

Simultaneously engineering a bowl-like and ultrafine nano-size structure offers an attractive route to not only increase the utilization efficiency of noble metals, the specific surface areas and the availability of active sites, but also boost the structural robustness and long-term stability. However, a great challenge remains in terms of the methods of synthesis. Herein, we report a facile one-pot hydrothermal method for the preparation of hollow porous Pt nanobowls (NBs) assembled from ultrafine particles. N,N′-methylenebisacrylamide (MBAA) acts as a structure-directing agent that forms a self-template with Pt ions and drives the nucleation and assembly of Pt metals, resulting in the fabrication of Pt NBs from ultrafine particles. By virtue of their unique structure and morphology, the optimized Pt NBs exhibited enhanced electrocatalytic methanol oxidation reaction (MOR) activity with 3.1-fold greater mass activity and 2.6-fold greater specific activities compared with those of commercial Pt black catalysts, as well as excellent stability and anti-poisoning ability.

Highly dispersed CoPx nanoparticles supported on carbon cloth for the enhanced catalytic performance of methanol electro-oxidation

Direct methanol fuel cell (DMFC) is a potential commercial fuel cell technology that is presently hindered by the expensive noble metal materials of the anode. Developing a method to obtain a uniformly dispersed metal phosphide catalyst with narrow size distribution is still a challenge. In this work, cobalt oxide was deposited on carbon cloth (CC) through atomic layer deposition (ALD), then cobalt phosphide was obtained after the phosphorization process. By changing the number of ALD-based ozone pulses (ALD-O3) for CC, the nucleation and growth modes of cobalt oxide (ALD-CoOx) on the CC were regulated, and CoPx nanoparticles with small particle size and uniform distribution were obtained. The optimized CoPx-based catalyst with 40 cycles of ALD-O3 treatment (CoPx/40-CC) exhibits excellent activity (153 mA/cm2) toward methanol electrocatalytic oxidation reaction in the alkaline solution, which is higher than the catalyst prepared by impregnation (Imp-CoPx/CC), although the CoPx loading of CoPx/40-CC is lower than that of Imp-CoPx/CC. The results indicate that the enhanced activity benefits from the small particle size and the uniform CoPx distribution, which promote the electron-transfer and mass transport kinetics of the methanol electro-oxidation process.

NiSe@Ni12P5 hierarchical nanorod arrays coupled on nickel-copper foam for highly efficient urea oxidation

Electrocatalytic urea oxidation reaction (UOR) is one of the most promising energy-saving alternatives to anodic oxygen evolution reaction (OER), and the development of efficient and stable catalysts for UOR is crucial. Therefore, in this paper, hierarchical structure NiSe@Ni12P5/NCF with Ni12P5 nanorod arrays coupled with NiSe nanospheres are synthesized on bare nickel-copper foam (NCF) by exogenous phosphorylation and subsequent electrodeposition methods. The catalytic performance of hierarchical structure NiSe@Ni12P5/NCF in urea-assisted electrolytic water reaction is studied in focus. The results show that the potential of NiSe@Ni12P5/NCF was only 1.267 V and 1.412 V vs RHE at current densities of 10 mA cm−2 and 100 mA cm−2, respectively, in addition to no significant activity decay after 140 h stability test. This is attributed to the fact that the introduction of NiSe regulated the interfacial charge distribution, creating an interfacial coupling effect that can greatly increase the original catalytic species, as well as the NiOOH species generated during the UOR process as true active sites, which ultimately improving the electrocatalytic UOR performance of NiSe@Ni12P5/NCF. This study provides a new idea for the preparation of hierarchical selenide - phosphides for electrochemical applications.

Limitations of Electrochemical Nitrogen Oxidation toward Nitrate.

The electrocatalytic N2 oxidation reaction (NOR) using renewable electricity is a promising alternative to the industrial synthesis of nitrate from NH3 oxidation. However, breaking the triple bond in the nitrogen molecule is one of the most essential challenges in chemistry. In this work, we use density functional theory simulations to investigate the plausible reaction mechanisms of electrocatalytic NOR and its competition with oxygen evolution reaction (OER) at the atomic scale. We focus on the electrochemical conversion of inert N2 to active *NO during NOR. We propose formation of *N2O from *N2 and *O as the rate-determining step (RDS). Following the RDS, a microkinetic model is utilized to study the rate of NOR on metal oxides. Our results demonstrate that a lower activation energy is obtained when a catalyst binds *O weakly. We show that the reaction is extremely challenging but also that design strategies have been suggested to promote electrochemical NOR.

Facet-Controlled PdP Nanosheets for Ethanol Electrooxidation

Understanding the contribution of crystal facets to the adsorption/desorption behavior of catalytic reaction intermediates is crucial for the design of high-performance electrocatalysts. In this work, we designed a synthesis strategy for ultrathin PdP nanosheets enclosed by different low-index facets, for example, {100}, {110}, and {111}, and studied their performance for electrocatalytic ethanol oxidation reaction (EOR). The results showed that the mass activity of the PdP nanosheets enclosed by the {100} facet was 4.07 A/mg, which was 1.43, 2.56, and 5.58 times as high as that of the PdP {110}, PdP {111}, and commercial Pd/C, respectively. Additionally, the PdP {100} displayed the best stability and the lowest activation energy (Ea), which further proved that the atomic configuration on the crystallographic {100} facet was greatly beneficial for EOR. The universality of this synthesis strategy was shown by producing nanocrystals with various amounts of P doping and elemental compositions (e.g., {100}-exposed PdAgP, PdAuP, PdCuP, and PdPtP).

Sol-Gel Synthesized High Entropy Metal Oxides as High-Performance Catalysts for Electrochemical Water Oxidation.

Hexanary high-entropy oxides (HEOs) were synthesized through the mechanochemical sol-gel method for electrocatalytic water oxidation reaction (WOR). As-synthesized catalysts were subjected to characterization, including X-ray diffraction (XRD), Fourier transforms infrared (FTIR) analysis, and scanning electron microscopy (SEM). All the oxide systems exhibited sharp diffraction peaks in XRD patterns indicating the defined crystal structure. Strong absorption between 400–700 cm−1 in FTIR indicated the formation of metal-oxide bonds in all HEO systems. WOR was investigated via cyclic voltammetry using HEOs as electrode platforms, 1M KOH as the basic medium, and 1M methanol (CH3OH) as the facilitator. Voltammetric profiles for both equiatomic (EHEOs) and non-equiatomic (NEHEOs) were investigated, and NEHEOs exhibited the maximum current output for WOR. Moreover, methanol addition improved the current profiles, thus leading to the electrode utility in direct methanol fuel cells as a sequential increase in methanol concentration from 1M to 2M enhanced the OER current density from 61.4 to 94.3 mA cm−2 using NEHEO. The NEHEOs comprising a greater percentage of Al, ([Al0.35(Mg, Fe, Cu, Ni, Co)0.65]3O4) displayed high WOR catalytic performance with the maximum diffusion coefficient, D° (10.90 cm2 s−1) and heterogeneous rate constant, k° (7.98 cm s−1) values. These primary findings from the EC processes for WOR provide the foundation for their applications in high-energy devices. Conclusively, HEOs are proven as novel and efficient catalytic platforms for electrochemical water oxidation.

Unusual Role of the Surfactant in the Self-Assembly of Pt Alloy in Ordered Mesoporous Carbon: Tuning the Nanocluster Size

In the one-step self-assembly synthesis of metallic nanocrystals in ordered mesoporous carbon (OMC), the surfactant functionalizes well as the structure directing agent and mesopore template. Interestingly, this work demonstrates another unusual role the surfactant plays: tuning the size of the nanocrystals. Our investigation shows that the decreasing molecular weight of the PS segment of PEO-b-PS leads to sequentially reduced PtRu particle sizes of 4.4, 3.9, and 2.9 nm, while F127 which has a distinctly smaller hydrophobic PO domain with a bending structure in the micelles successfully results in sub-2 nm PtM (M = Ru, Ir, Rh, Pd) nanoclusters in OMC. This well indicates that the nanocluster size is largely decided by the volume of the hydrophobic segment of the surfactant to which the metallic precursor is linked. The smaller the volume, the fewer the precursor molecules are adsorbed, and the smaller the alloy nanoclusters. In the electrocatalytic methanol oxidation reaction, the mass activity of PtRu-1.6/OMC with 1.6 nm PtRu clusters at 0.87 V reaches 1.07 A mgPt-1, which is 2.9 times that of commercial PtRu/C with an average alloy size of 2.7 nm. In principle, a wide range of ultrafine metallic clusters embedded in OMC can be prepared via this route for various applications.