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Combining Pd with oxophilic species and appropriate catalyst supports is regarded as an effective approach to strengthen the intrinsic electrocatalytic performance of ethanol oxidation reaction (EOR). In this work, palladium nanocrystals (NCs) modified with Bi (OH) 3 were successfully immobilized on the three-dimensional nitrogen-doped graphene (Pd–Bi(OH) 3 /NG) via a simple one-pot route. The resulting Pd–Bi(OH) 3 /NG demonstrates exceptional electrocatalytic performance for EOR under alkaline conditions, exhibiting enhanced mass and specific activity, kinetics, durability and long-term stability, significantly surpassing that of commercial Pd/C. Notably, the electrocatalytic performance of Pd–Bi(OH) 3 /NG-2 (with an atomic ratio of Pd/Bi at 7:1) is the best among all the tested electrocatalysts. The results reveal that the improved electrocatalytic activity of Pd–Bi(OH) 3 /NG may stem from the significant contributions of the Bi(OH) 3 species decorating of the Pd NCs and their incorporation into the nitrogen-doped graphene. • Pd NCs with surface decoration of Bi(OH) 3 species anchored on NG was firstly fabricated. • The Pd–Bi(OH) 3 /NG achieves a superior electrocatalytic performance for alkaline EOR. • The exciting EOR behavior is owing to surface decoration of Bi(OH) 3 around Pd NCs. • The exciting EOR behavior is also derive from the embedding into NG. [ABSTRACT FROM AUTHOR]

Substituting thermodynamically favorable ethanol oxidation reaction (EOR) for oxygen evolution reaction (OER) engenders high‐efficiency hydrogen production and generates high value‐added products as well. However, the main obstacles have been the low activity and the absence of an explicit catalytic mechanism. Herein, a heterostructure composed of amorphous vanadium oxide and crystalline nickel nitride (VOx−Ni3N) is developed. The heterostructure immensely boosts the EOR process, achieving the current density of 50 mA cm−2 at the low potential of 1.38 V versus reversible hydrogen electrode (RHE), far surpassing the sluggish OER (1.65 V vs RHE). Electrochemical impedance spectroscopy indicates that the as‐fabricated heterostructure can promote the adsorption of OH− and the generation of the reactive species (O*). Theoretical calculations further outline the dual polarization of the Ni site at the interface, specifically the asymmetric charge redistribution (interfacial polarization) and in‐plane polarization. Consequently, the dual polarization modulates the d‐band center, which in turn regulates the adsorption/desorption strength of key reaction intermediates, thereby facilitating the entire EOR process. Moreover, a VOx−Ni3N‐based electrolyzer, coupling hydrogen evolution reaction (HER) and EOR, attains 50 mA cm−2 at a low cell voltage of ≈1.5 V. This work thus paves the way for creating dual polarization through interface engineering toward broad catalysis. [ABSTRACT FROM AUTHOR]

The design of efficient electrocatalysts for ethanol oxidation is essential for commercializing direct ethanol fuel cells (DEFCs). In this strategy, a mesoporous carbon microsphere (MC) was first synthesized by inverting the micro-emulsion technique. The MC@Au/Pd catalyst with a particular core-shell structure was obtained by utilizing mesoporous carbon as a core to load the Au/Pd layer. The novelty of the MC@Au/Pd catalyst with specialized core-shell structures lies not only in the high specific surface area inherited from the carbon core but also in the strong electronic interactions caused by the lattice mismatch between the core (Au) and shell (Pd) atoms. Particularly, electrochemical measures demonstrated that the Au/Pd catalyst exhibits superior catalytic activity toward the ethanol oxidation reaction (EOR) compared with commercial Pd/C catalysts. This is mainly due to the high specific surface area and mesoporous pore size inherited from the core carbon microspheres. In addition, the mesoporous carbon core and Au/Pd shell in the well-organized core-shell catalyst (MC@Au/Pd) influence the catalytic activity for ethanol oxidation by adjusting the electronic structure of Pd. [Display omitted] • A novelty carbon core/Au–Pd shell structure catalyst was first synthesized. • The carbon core provides an abundance of mass transfer channels for EOR. • The well-organized catalyst exhibit enhanced catalytic activity for EOR. [ABSTRACT FROM AUTHOR]

With respect to the potential of palladium (Pd)‐based nanomaterials in catalyzing typical electrochemical reactions, herein, a strategy that couples the quick Joule‐heating with a solid phase synthesis for producing carbon‐supported Pd–Se nanoparticles with welcome features is reported, e.g., fine sizes, clean surfaces, and controlled crystal phases toward electrocatalysis of oxygen reduction reaction (ORR) and ethanol oxidation reaction (EOR) in an alkaline medium. Principally, the introduction of Se into Pd alters its electronic properties and weakens the adsorption of key reaction intermediates on the Pd–Se nanoparticles during the ORR and EOR process, thus endowing them with better electrocatalysis for the same electrochemical reactions. Impressively, the carbon‐supported Pd–Se nanoparticles exhibit phase‐dependent electrocatalysis toward ORR and EOR. In particular, the cubic Pd17Se15 nanoparticles supported on carbon substrate show mass activity of 0.206 A mgPd−1 and specific activity of 0.546 mA cm−2 at 0.9 V for ORR in 0.1 m KOH electrolyte, while the orthorhombic PdSe2 nanoparticles show a mass activity of 3.79 A mgPd−1 for EOR, higher than that of their cubic counterpart and commercial Pd/C catalyst. The universality of this synthetic strategy in manufacturing carbon‐supported noble metal chalcogenide nanoparticles and highlighting its potential in designing highly efficient electrocatalysts are emphasized. [ABSTRACT FROM AUTHOR]

The development of non-precious metal bifunctional electrocatalysts is of practical significance to solve resource shortage and energy crisis. In this study, to accelerate mass/electron transfer and maximize the area of exposed active sites, a coral-like Sn–Co–P/NF bi-functional electrocatalyst was synthesized by electrodeposition for total hydrolysis. Ethanol oxidation reaction (EOR) was used to replace oxygen evolution reaction (OER) with hydrogen evolution reaction (HER) to further improve the water electrolysis rate. The catalyst showed great electrochemical activity and stability in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under alkaline conditions. At a current density of 10 mA cm−2, the required overpotential for HER is only 59 mV (vs. RHE) and 304 mV (vs. RHE) for OER, and the corresponding Tafel slopes are 42 mV·dec−1 and 67 mV·dec−1, respectively. When EOR was substituted for anodic oxygen evolution, the overpotential could be reduced by 240 mV. In addition, when Sn–Co–P/NF is used as a water-ethanol electrolytic cell assembled with anode and cathode, the current density of 10 mA cm−2 can be reached with only 1.49 V operating voltage, which is 130 mV lower than that of hydrolysis alone, and it also shows good durability in the test of 28 h. Therefore, the experimental results show that it is feasible to use EOR instead of OER to coupling with HER, the catalyst has broad application prospects in industrial electrolysis. [Display omitted] • The coral-shaped Sn–Co–P/NF bifunctional catalysts with amorphous structure is prepared. • The Sn–Co–P/NF catalysts has excellent bifunctional catalytic activity for HER and EOR. • Sn Doping regulated the electronic structure of Co and P and exhibited a synergistic catalytic effect. [ABSTRACT FROM AUTHOR]

In the present work, exfoliated graphitic carbon nitride (g‐CN) is immobilized on carbon paper substrates by a simple electrophoretic route, and subsequently decorated with ultra‐low amounts (≈μg/cm2) of Pt nanoparticles (NPs) by cold plasma sputtering. Optimization of preparative conditions allowed a fine tuning of Pt NPs size, loading and distribution and thus a controlled tailoring of g‐CN/Pt interfacial interactions. Modulation of such features yielded g‐CN‐Pt‐based anode materials with appealing activity and stability towards the ethanol oxidation reaction (EOR) in alkaline aqueous solutions, as revealed by electrochemical tests both in the dark and under irradiation. The present results provide new insights on the design of nano‐engineered heterocomposites featuring improved performances thanks to Pt coupling with g‐CN, a low‐cost and environmentally friendly visible light‐active semiconductor. Overall, this work might open attractive avenues for the generation of green hydrogen via aqueous ethanol electrolysis and the photo‐promoted alcohol electrooxidation in fuel cells. [ABSTRACT FROM AUTHOR]

Searching and designing high-quality support materials is a strategy for rationally designing electrocatalysts for the ethanol oxidation reaction (EOR). In this work, the ketjen black (KB) embedded with nitrogen-doped graphene based aerogel (NG) anchoring palladium nanocrystals (Pd/KB@NG) was prepared through a one-step hydrothermal method. As a catalyst for EOR, Pd/KB@NG-2 (the mass ratio of graphene oxide and KB is 2:1) has significantly improved electrocatalytic performance compared with commercial Pd/C and other counterparts. The Pd nanocrystals were selectively anchored on the interface composed of KB and NG owing to the spatial confinement effect. Despite the higher Pd content (13.4 wt %), Pd nanocrystals (Pd NCs) are densely and uniformly dispersed between KB and NG on account of the anchoring and confinement effects of KB. The spatial confinement effect can also prevent the loss of the precious metal Pd, thereby improving the electrocatalytic activity and stability of the samples. Moreover, the electron-donating property of KB induces the electrons to flow from KB to Pd NCs, which enhances the electronic metal–support interaction, thus optimizing the adsorption behavior of toxic intermediate CH3COads and improving the electrocatalytic performance of the catalysts. In addition, the embeddedness of the highly conductive KB between NG not only endows fast channels to transfer interelectrons from the supports to the active metal but also generates the large number of pore structures, thereby creating the siphon effect and accelerating the mass transfer process during the process of EOR. Based on the spatial confinement effect, this work not only provides a perspective for the rational design of highly active catalysts but also opens an avenue to a generation of Pd-based catalysts for DEFCs and beyond. [ABSTRACT FROM AUTHOR]

Metastable‐phase intermetallic compounds (IMCs) provide great flexibility to modify the electronic structure and surface coordination environment of metallic catalysts for various reactions. However, the synthesis of metastable‐phase IMCs with high catalytic performance remains a great challenge due to their thermodynamically unstable nature. Here, a wet‐chemical epitaxial growth strategy to synthesize metastable‐phase Pd‐Bi intermetallic nanocrystals (NCs) is reported. β‐Pd3Bi and γ‐Pd5Bi3 intermetallic NCs are epitaxially grown on the templates of face‐centered cubic Pd3Pb nanocubes and hexagonal close‐packed PtBi nanoplates, achieving Pd3Pb@Pd3Bi and PtBi@Pd5Bi3 core–shell NCs, respectively. The obtained Pd3Pb@Pd3Bi NCs possess a mass activity and specific activity of 8.52 A mg−1Pd and 11.59 mA cm−2 for ethanol oxidation reaction, which is 7.5 and 3.6 times as high as those of commercial Pd/C, respectively. Meanwhile, Pd3Pb@Pd3Bi NCs possess superior stability than commercial Pd/C. This work advances the design and synthesis of high‐performance metastable‐phase IMCs, opening an avenue for electrocatalytic ethanol oxidation and beyond. [ABSTRACT FROM AUTHOR]

Pd nanoparticles (PdNPs) are deposited electrochemically on the glassy carbon electrode surface using PdCl 2 dissolved in a deep eutectic solvent composed of choline chloride and urea (reline). The morphology and particle size of the PdNPs are determined from SEM exhibiting a homogeneous distribution with potential deposition depending on particle size. The particles display a core-shell morphology, consisting of Pd(0) as the core and Pd(OH) 2 as the shell. The ethanol oxidation reaction, EOR, is evaluated at different KOH concentrations. The electrocatalyst with the highest mass activity is achieved at −750 mV potential deposition and 1 M KOH, exhibiting 3126 ± 606 mAmg Pd −1. However, when 0.1 M KOH is used the mass activity decreases to one-third the value obtained at 1 M KOH. Notwithstanding, the mass activity displayed by these PdNPs is superior to that reported for other Pd-based nanoparticles synthesized using more complex, time-consuming and costly methods reported in the literature. [Display omitted] • PdNPs were prepared by electrodeposition method using reline as DES. • The morphology of the electrodeposited PdNPs is core-shell Pd@Pd(OH) 2. • PdNPs electrodeposited at −750 mV was the best MA for EOR using 1 M KOH. • Different KOH concentrations were employed to evaluate the EOR. • The optimal concentration of KOH in the EOR was 1 M followed by 0.5 and 0.1 M. [ABSTRACT FROM AUTHOR]

Securing ever-increasing energy demands while reducing resilience on fossil fuels is a major task of modern society. Fuel cells are devices in which the chemical energy of various fuels can be converted into clean electricity. Direct ethanol fuel cells (DEFC) are increasingly popular for their eco-friendliness and significantly easier liquid fuel manipulation compared to hydrogen-fed fuel cells. Carbon-supported Pt nanoparticles are considered reference catalysts for fuel oxidation in DEFCs. Several challenges hinder DEFC commercialization: high Pt-loading, Pt poisoning by CO intermediates, and the instability of the Pt and carbon supports. This work demonstrates an efficient electrocatalyst for ethanol oxidation reaction (EOR) composed of Pt nanoparticles supported on electrochemically exfoliated graphene (Pt/el-rGO). Graphene was obtained through anodic electrochemical exfoliation using graphitic tape as the anode, while Pt nanoparticles were synthesized using chemical reduction with formic acid. As-obtained Pt/el-rGO with only 7.5 wt.% Pt was characterized using TEM, SEM, and XPS. Pt/el-rGO exhibited notably higher EOR catalytic activity in an alkaline electrolyte than the Pt/C benchmark. This enhancement can be linked with the functional groups present on the graphene support, which facilitate ethanol dehydrogenation as the first step in the EOR mechanism and thus enhance reaction kinetics on Pt-active sites. [ABSTRACT FROM AUTHOR]

The most widely used support in low-temperature fuel cell applications is the commercially available Vulcan XC-72. Herein, we report its functionalization with the home-obtained mesityl copper (Cu-mes) and Cu coordinate (Cu-(dmpz)-L2) organometallic compounds. Pd nanoparticles are anchored on the supports obtaining Pd/CCu‑mes, Pd/CCu(dmpz)L2, and Pd/C (on nonfunctionalized support). The polarization curves of the ethanol oxidation reaction (EOR) show that Pd/CCu‑mes and Pd/CCu(dmpz)L2 promote the reaction at a more negative onset potential, i.e., Eonset = 0.38 V/reversible hydrogen electrode (RHE), compared to 0.41 V/RHE of Pd/C. The mass current density (jm) delivered by Pd/CCu‑mes is considerably higher (1231.3 mA mgPd–1), followed by Pd/CCu(dmpz)L2 (1001.8 mA mgPd–1), and Pd/C (808.3 mA mgPd–1). The enhanced performance of Pd/CCu‑mes and Pd/CCu(dmpz)L2 for the EOR (and tolerance to CO poisoning) is attributed to a shift of their d-band center toward more negative values, compared to Pd/C, because of the formation of PdCu alloyed phases arising from the functionalization. In addition, laboratory-scale tests of the anion exchange membrane-direct ethanol fuel cell assembled with Pd/CCu‑mes show the highest open circuit voltage (OCV = 0.60 V) and cell power density (Pcell = 0.14 mW cm–2). As a result of its high catalytic activity, Pd/CCu‑mes can find application as an anode nanocatalyst in AEM-DEFCs. [ABSTRACT FROM AUTHOR]

Direct ethanol fuel cells (DEFCs) have been widely considered as a feasible power conversion technology for portable and mobile applications. The economic feasibility of DEFCs relies on two conditions: a notable reduction in the expensive nature of precious metal electrocatalysts and a simultaneous remarkable improvement in the anode's long-term performance. Despite the considerable progress achieved in recent decades in Pt nanoengineering to reduce its loading in catalyst ink with enhanced mass activity, attempts to tackle these problems have yet to be successful. During the ethanol oxidation reaction (EOR) at the anode surface, Pt electrocatalysts lose their electrocatalytic activity rapidly due to poisoning by surface-adsorbed reaction intermediates like CO. This phenomenon leads to a significant loss in electrocatalytic performance within a relatively short time. This review provides an overview of the mechanistic approaches during the EOR of noble metal-based anode materials. Additionally, we emphasized the significance of many essential factors that govern the EOR activity of the electrode surface. Furthermore, we provided a comprehensive examination of the challenges and potential advancements in electrocatalytic EOR. [ABSTRACT FROM AUTHOR]

Tailoring the surface structure of the mesoporous metal catalysts is pivotal for influencing both the catalytic activity and selectivity. Through the dealloying of bimetallic alloys, surface modification is achieved by dissolving unstable components, thereby forming a multitude of catalytically active sites. In this study, highly enhanced electrocatalysts are fabricated via chemical etching of mesoporous AuCu alloy nanoparticles prepared through the self‐assembly of micelles. The presence of large mesoporosity (>10 nm) with rich defect sites on the surface, along with the synergistic effect arising from the AuCu bimetallic alloy, effectively boosts electrocatalytic performance for the ethanol oxidation reaction. This strategy demonstrates a promising strategy to further enhance the catalytic performance of Au‐based mesoporous nanoparticles by eliminating the unstable metal component and refining the mesoporous structure with an abundance of various active sites. [ABSTRACT FROM AUTHOR]

Pd-based catalysts exhibit higher catalytic activity and durability in many electrochemical reactions. However, the electrochemical performance can be further enhanced by fine-tune of the alloy composition. Although binary alloys have been fully studied, the multicomponent alloys are far beyond understanding, which leaves cocktail effect a compromised explanation for the high-entropy alloy. Herein Pd nanosheet-seeded growth was used to synthesize a Pd-Zn-Cd ternary alloy by accurately controlling the Pd-Zn-Cd molar ratio through adjusting the amount of introduced Cd precursor. Through analysis of the crystal phase structure of PdCdZnx and PdZnxCd1−x, the competitive relationship of Zn and Cd in the alloying process with Pd was unveiled: Pd1Cd1 intermetallics (IMC) is thermodynamically favored over Pd1Zn1 IMC in the ternary system. However, the increased structure stability of PdCd over PdZn does not bring about increased durability in the catalytic ethanol oxidation reaction. The morphology selection of Pd seeds is also crucial for the study, as Pd cubes, Pd tetrahedrons, and Pd octahedrons do not form PdZn in the same protocol. The successful alloying through the seeded growth depends on the maximum diffusion depth of foreign atoms into the seed. [ABSTRACT FROM AUTHOR]

Abstract Direct ethanol fuel cells (DEFCs) have been widely considered as a feasible power conversion technology for portable and mobile applications. The economic feasibility of DEFCs relies on two conditions: a notable reduction in the expensive nature of precious metal electrocatalysts and a simultaneous remarkable improvement in the anode's long-term performance. Despite the considerable progress achieved in recent decades in Pt nanoengineering to reduce its loading in catalyst ink with enhanced mass activity, attempts to tackle these problems have yet to be successful. During the ethanol oxidation reaction (EOR) at the anode surface, Pt electrocatalysts lose their electrocatalytic activity rapidly due to poisoning by surface-adsorbed reaction intermediates like CO. This phenomenon leads to a significant loss in electrocatalytic performance within a relatively short time. This review provides an overview of the mechanistic approaches during the EOR of noble metal-based anode materials. Additionally, we emphasized the significance of many essential factors that govern the EOR activity of the electrode surface. Furthermore, we provided a comprehensive examination of the challenges and potential advancements in electrocatalytic EOR. Graphic abstract

PdCu nanorings (NRs) featuring hollow interiors and low coordinated sites are synthesized as efficient electrocatalysts for ethanol and ethylene glycol oxidation reactions. [Display omitted] Two-dimensional (2D) Pd-based nanostructures with a high active surface area and a large number of active sites are commonly used in alcohol oxidation research, whereas the less explored ring structure made of nanosheets with large pores is of interest. In this study, we detail the fabrication of PdCu nanorings (NRs) featuring hollow interiors and low coordinated sites using a straightforward solvothermal approach. Due to increased exposure of active sites and the synergistic effects of bimetallics, the PdCu NRs exhibited superior catalytic performance in both the ethanol oxidation reaction (EOR) and the ethylene glycol oxidation reaction (EGOR). The mass activities of PdCu NRs for EOR and EGOR were measured at 7.05 A/mg and 8.12 A/mg, respectively, surpassing those of commercial Pd/C. Furthermore, the PdCu NRs demonstrated enhanced catalytic stability, maintaining higher mass activity levels compared to other catalysts during stability testing. This research offers valuable insights for the development of efficient catalysts for alcohol oxidation. [ABSTRACT FROM AUTHOR]

Efficient ethanol oxidation reaction (EOR) catalysts with anti‐poisoning ability and high selectivity are in high demand for the widespread application of direct ethanol fuel cells (DEFCs). Here, the PdSnW ternary alloy nanoparticles are synthesized by a facile solvothermal method and exhibit an enhanced EOR catalytic performance. CO stripping experiment, X‐ray photoelectron spectroscopy and in situ Fourier transform infrared are employed to study the correlation between catalyst structure and EOR catalytic performance. The oxyphilic Sn and W not only provide dangling O−H bond, accelerating the subsequent oxidation of adsorbed intermediate CO species, but also moderate the electron state of Pd, enhancing the adsorption of CH3CH2OH, thus resulting in the promotion of C−C bond cleavage and an increased C1 selectivity. As a consequence, PdSnW alloy nanoparticle catalyst exhibit a better stability and a higher mass activity than those of Pd/C, PdSn and PdW, respectively. This work not only offers novel insights to strategically design highly efficient electrocatalysts for ethanol oxidation, but also further clarifies the inherent structure‐activity relationship. [ABSTRACT FROM AUTHOR]

The inefficiency of ethanol oxidation reaction (EOR) presents a significant obstacle in harnessing renewable biofuels with high energy density into electricity. Despite efforts, most Pt-based catalysts still suffer from drawbacks such as poor activity and susceptibility to CO poisoning, particularly in acidic conditions. Herein, we employed a physical laser-assisted approach to synthetize a PtPd alloy with a 1:1 atomic ratio. This alloy demonstrates remarkable performance in acidic EOR, boasting a high mass activity of 1.86 A·mgPt−1 and competitive resistance to poisoning. Combining in situ synchrotron radiation infrared spectroscopy with theoretical calculations, we reveal that the synergic interaction between Pt and Pd enhances both the adsorption of OH* intermediate and the dehydrogenation ability of ethanol. This work will prove the feasibility of synthesizing bimetallic alloys by a physical laser-assisted strategy and promote the development of advanced alloy electrocatalysts. [ABSTRACT FROM AUTHOR]

The inefficiency of Pt and Pd benchmark catalysts in achieving complete ethanol oxidation, coupled with their inherent susceptibility to poisoning, poses a significant obstacle to the advancement of direct ethanol fuel cells. In this study, the development of self‐supported and ultrathin RhCuBi trimetallenes, demonstrating exceptional performance in ethanol electrooxidation through segregation and interface engineering is presented. The distinctive RhBi‐rich crystalline/RhCu‐rich amorphous heterostructure of RhCuBi trimetallenes creates a wealth of highly active interfacial sites for the ethanol oxidation reaction (EOR). This results in an impressive 43.3% Faradaic efficiency for the C1 pathway and a peak mass activity of 1.11 A mgRh−1 at 0.68 V versus reversible hydrogen electrode. Moreover, RhCuBi trimetallenes retain 60% of their initial mass activity after 8.5 h of constant potential electrolysis, outperforming commercial Pd and Pt catalysts (<3%). In/ex situ infrared spectroscopy directly reveals the generated C1 products and the key CH3CO* intermediates for EOR on RhCuBi trimetallenes. Theoretical calculations confirm that the RhBi alloy, particularly the lattice‐stretched crystalline/amorphous interfacial sites, facilitates the adsorption/activation of ethanol and the dehydrogenation of CH3CO* toward the C1 pathway of EOR. This breakthrough offers promising prospects for enhancing the efficiency and stability of ethanol electrooxidation in fuel cell applications. [ABSTRACT FROM AUTHOR]

Palladium (Pd)-based catalysts have been extensively investigated in direct ethanol fuel cells (DEFCs) since the urgent energy and environmental problems. Rational design Pd-based catalyst with outstanding structure can optimize its electrocatalytic performance for ethanol oxidation reaction (EOR) catalyst. In this work, a facile strategy was proposed to prepare AuPd nanochain networks (NNWs) with core-shell structure by adjusting the reduction rate by slowly dropping the acidic reducing agent to the alkaline precursor solution system. The resulting catalysts exhibit a porous self-supporting structure with twisted features, exposing a large number of active sites. The optimized AuPd NNWs catalyst displays much-improved activity (3289.62 mA mg−1 Pd) and greatly enhanced electrocatalytic stability for EOR in comparison with that of commercial Pd/C catalysts. This enhanced activity can be attributed to the synergic effect of the Pd shell with the Au core as well as the twisted and self-supporting structure which can expose much more active sites and provide rich mass and electron transfer channels. [Display omitted] • A precise strategy was proposed to prepare heterogeneous AuPd core-shell nanochain networks using a one pot method. • The obtained AuPd core-shell nanochain networks consist of self-supported porous structure with rich active sites. • Electronic structure of Pd was optimized by the interaction of Au core with Pd shell. • The optimized AuPd core-shell nanochain networks display enhanced activity and stability toward EOR. [ABSTRACT FROM AUTHOR]

Direct ethanol fuel cell (DEFC) is promising source for mobile and portable applications, but the electrocatalysts are based on metal noble alloys or doping elements to minimize the incomplete ethanol oxidation and poisoning effect. While the main problem persists, this study describes the enhancement of ethanol oxidation reaction by adding graphene (G) to Vulcan XC-72R carbon black (C) metal support, with different C/G ratios. The Graphene was prepared from exfoliated graphite following by dried at ambient temperature. The 60 wt% graphene hybrid support enhances the current density at 5% cyclic voltammetry (CV) and 127% chronoamperometry (CA) higher than carbon pure support in acid electrolyte, whereas in alkaline, graphene (60 wt%) showed the highest electrochemical activity with an increase of current 82% (CV) and 130% (CA). Therefore, we demonstrated the enhancement of the catalyst electrochemical activity in both electrolytes through a simple synthesis method. The 40 wt% carbon and 60 wt% graphene hybrid support achieving higher performance in ethanol oxidation, evidencing a potential application in DEFC. [ABSTRACT FROM AUTHOR]

Direct liquid fuel cells (DLFC) are regarded as attractive energy devices with their advantages of sustainability and eco‐friendly operation. Pd‐based materials have been recognized as ideal catalysts for anodic oxidation of DLFC. Although reasonably regulating the structure of Pd‐based catalysts to achieve remarkable catalytic performance, it is not clear about the combined effects of d‐band center and charge transfer, which are the crucial impactors for catalytic activity. Herein, a facile method to synthesize trimetallic PdCuIn nanoparticles (PdCuIn NPs) for ethanol and formate oxidation reactions (EOR and FOR, respectively) is reported. PdCuIn NPs exhibits bifunctional catalytic activities for both EOR and FOR, with mass activities of 16 000 and 15 500 mA mgPd−1, respectively, which are much better than those of commercial Pd/C catalysts. Comparing to the bimetallic nanoparticles (PdCu or PdIn NPs), additional Cu or In enhances the electron transfer and achieves a suitable d‐band center, resulting in excellent performance. This work synthesizes a highly active catalyst for both EOR and FOR, but also provides facile strategy of balancing the d‐band center and charge transfer for high catalytic performance. [ABSTRACT FROM AUTHOR]

Abstract Substituting thermodynamically favorable ethanol oxidation reaction (EOR) for oxygen evolution reaction (OER) engenders high‐efficiency hydrogen production and generates high value‐added products as well. However, the main obstacles have been the low activity and the absence of an explicit catalytic mechanism. Herein, a heterostructure composed of amorphous vanadium oxide and crystalline nickel nitride (VOx−Ni3N) is developed. The heterostructure immensely boosts the EOR process, achieving the current density of 50 mA cm−2 at the low potential of 1.38 V versus reversible hydrogen electrode (RHE), far surpassing the sluggish OER (1.65 V vs RHE). Electrochemical impedance spectroscopy indicates that the as‐fabricated heterostructure can promote the adsorption of OH− and the generation of the reactive species (O*). Theoretical calculations further outline the dual polarization of the Ni site at the interface, specifically the asymmetric charge redistribution (interfacial polarization) and in‐plane polarization. Consequently, the dual polarization modulates the d‐band center, which in turn regulates the adsorption/desorption strength of key reaction intermediates, thereby facilitating the entire EOR process. Moreover, a VOx−Ni3N‐based electrolyzer, coupling hydrogen evolution reaction (HER) and EOR, attains 50 mA cm−2 at a low cell voltage of ≈1.5 V. This work thus paves the way for creating dual polarization through interface engineering toward broad catalysis.

Tailoring the surface structure of the mesoporous metal catalysts is pivotal for influencing both the catalytic activity and selectivity. Through the dealloying of bimetallic alloys, surface modification is achieved by dissolving unstable components, thereby forming a multitude of catalytically active sites. In this study, highly enhanced electrocatalysts are fabricated via chemical etching of mesoporous AuCu alloy nanoparticles prepared through the self‐assembly of micelles. The presence of large mesoporosity (>10 nm) with rich defect sites on the surface, along with the synergistic effect arising from the AuCu bimetallic alloy, effectively boosts electrocatalytic performance for the ethanol oxidation reaction. This strategy demonstrates a promising strategy to further enhance the catalytic performance of Au‐based mesoporous nanoparticles by eliminating the unstable metal component and refining the mesoporous structure with an abundance of various active sites.

Abstract The potential of metal oxides in electrochemical energy storage encouraged our research team to synthesize molybdenum oxide/tungsten oxide nanocomposites (MoO3/WO3) and their hybrid with reduced graphene oxide (rGO), in the form of MoO3/WO3/rGO as a substrate with relatively good electrical conductivity and suitable electrochemical active surface. In this context, we presented the electrochemical behavior of these nanocomposites as an electrode for supercapacitors and as a catalyst in the oxidation process of methanol/ethanol. Our engineered samples were characterized by X-ray diffraction pattern and scanning electron microscopy. As a result, MoO3/WO3 and MoO3/WO3/rGO indicated specific capacitances of 452 and 583 F/g and stability of 88.9% and 92.6% after 2000 consecutive GCD cycles, respectively. Also, MoO3/WO3 and MoO3/WO3/rGO nanocatalysts showed oxidation current densities of 117 and 170 mA/cm2 at scan rate of 50 mV/s, and stability of 71 and 89%, respectively in chronoamperometry analysis, in the MOR process. Interestingly, in the ethanol oxidation process, corresponding oxidation current densities of 42 and 106 mA/cm2 and stability values of 70 and 82% were achieved. MoO3/WO3 and MoO3/WO3/rGO can be attractive options paving the way for prospective alcohol-based fuel cells.

The potential of metal oxides in electrochemical energy storage encouraged our research team to synthesize molybdenum oxide/tungsten oxide nanocomposites (MoO3/WO3) and their hybrid with reduced graphene oxide (rGO), in the form of MoO3/WO3/rGO as a substrate with relatively good electrical conductivity and suitable electrochemical active surface. In this context, we presented the electrochemical behavior of these nanocomposites as an electrode for supercapacitors and as a catalyst in the oxidation process of methanol/ethanol. Our engineered samples were characterized by X-ray diffraction pattern and scanning electron microscopy. As a result, MoO3/WO3 and MoO3/WO3/rGO indicated specific capacitances of 452 and 583 F/g and stability of 88.9% and 92.6% after 2000 consecutive GCD cycles, respectively. Also, MoO3/WO3 and MoO3/WO3/rGO nanocatalysts showed oxidation current densities of 117 and 170 mA/cm2 at scan rate of 50 mV/s, and stability of 71 and 89%, respectively in chronoamperometry analysis, in the MOR process. Interestingly, in the ethanol oxidation process, corresponding oxidation current densities of 42 and 106 mA/cm2 and stability values of 70 and 82% were achieved. MoO3/WO3 and MoO3/WO3/rGO can be attractive options paving the way for prospective alcohol-based fuel cells. [ABSTRACT FROM AUTHOR]

Direct ethanol fuel cells (DEFCs) play an indispensable role in the cyclic utilization of carbon resources due to its high volumetric energy density, high efficiency, and environmental benign character. However, owing to the chemically stable carbon‐carbon (C─C) bond of ethanol, its incomplete electrooxidation at the anode severely inhibits the energy and power density output of DEFCs. The efficiency of C─C bond cleaving on the state‐of‐the‐art Pt or Pd catalysts is reported as low as 7.5%. Recently, tremendous efforts are devoted to this field, and some effective strategies are put forward to facilitate the cleavage of the C─C bond. It is the right time to summarize the major breakthroughs in ethanol electrooxidation reaction. In this review, some optimization strategies including constructing core–shell nanostructure with alloying effect, doping other metal atoms in Pt and Pd catalysts, engineering composite catalyst with interface synergism, introducing cascade catalytic sites, and so on, are systematically summarized. In addition, the catalytic mechanism as well as the correlations between the catalyst structure and catalytic efficiency are further discussed. Finally, the prevailing limitations and feasible improvement directions for ethanol electrooxidation are proposed. [ABSTRACT FROM AUTHOR]

The preparation of electrocatalysts with high performance for the ethanol oxidation reaction is vital for the large-scale commercialization of direct ethanol fuel cells. Here, we successfully synthesized a high-performance electrocatalyst of a AuPd alloy with a decreased alloying degree via pulsed laser irradiation in liquids. As indicated by the experimental results, the photochemical effect-induced surficial deposition of Pd atoms, combined with the photothermal effect-induced interdiffusion of Au and Pd atoms, resulted in the formation of AuPd alloys with a decreased alloying degree. Structural characterization reveals that L-AuPd exhibits a lower degree of alloying compared to C-AuPd prepared via the conventional co-reduction method. This distinct structure endows L-AuPd with outstanding catalytic activity and stability in EOR, achieving mass and specific activities as high as 16.01 A mgPd−1 and 20.69 mA cm−2, 9.1 and 5.2 times than that of the commercial Pd/C respectively. Furthermore, L-AuPd retains 90.1% of its initial mass activity after 300 cycles. This work offers guidance for laser-assisted fabrication of efficient Pd-based catalysts in EOR. [ABSTRACT FROM AUTHOR]

The anodic electrooxidation of ethanol to value-added acetate is an excellent example of replacing the oxygen evolution reaction to promote the cathodic hydrogen evolution reaction and save energy. Herein, we present a colloidal strategy to produce Ni-Fe bimetallic alloy nanoparticles (NPs) as efficient electrocatalysts for the electrooxidation of ethanol in alkaline media. Ni-Fe alloy NPs deliver a current density of 100 mA·cm−2 in a 1.0 M KOH solution containing 1.0 M ethanol merely at 1.5 V vs. reversible hydrogen electrode (RHE), well above the performance of other electrocatalysts in a similar system. Within continuous 10 h testing at this external potential, this electrode is able to produce an average of 0.49 mmol·cm−2·h−1 of acetate with an ethanol-to-acetate Faradaic efficiency of 80%. A series of spectroscopy techniques are used to probe the electrocatalytic process and analyze the electrolyte. Additionally, density functional theory (DFT) calculations demonstrate that the iron in the alloy NPs significantly enhances the electroconductivity and electron transfer, shifts the rate-limiting step, and lowers the energy barrier during the ethanol-to-acetate reaction pathway. [ABSTRACT FROM AUTHOR]

We report a mild, one‐pot synthesis of PdPtAuAgCuIr multimetallic nanocrystals with controlled shapes and explore their applications as the electrocatalysts for ethanol electrooxidation in alkaline medium. The success of current synthesis relies on the co‐reduction of six metal precursors in the presence of octadecylammonium chloride and ascorbic acid at an elevated temperature. The resulting products are featured with an in‐plane core‐shell structure, together with the trigonal/hexagonal plate decorated with granular edges. When serving as EOR electrocatalysts, the carbon‐supported PdPtAuAgCuIr nanocrystals exhibit more than five‐fold increase in mass activity as compared to that of commercial Pt/C, as well as improved reaction kinetics and long‐term durability. DFT calculations disclose that the reduced energy barrier renders the Pd‐based multimetallic catalyst in catalytic performance. The present study provides a feasible strategy to create multimetallic nanocrystals with controlled two‐dimensional morphology under ambient conditions, shedding light for rational design over advanced fuel cell catalysts composed of multimetallic alloy. [ABSTRACT FROM AUTHOR]

In this study, palladium particles supported on carbon black (Vulcan XC-72) (Pd/C) and corncob biochar (Pd/CB800, Pd/CB900, and Pd/CB1000) were successfully synthesized using borohydride reduction. The biochar support was obtained from corncob waste via pyrolysis from 800 to 1000°C. Scanning electron microscopy with energy dispersive x-ray (SEM–EDX) revealed successful deposition of Pd metal particles on the carbon support materials. X-ray diffraction (XRD) analysis confirmed the crystalline structures of Pd, and the crystallite size was found to be smallest in Pd/CB900. The electrocatalytic activity of the Pd electrocatalyst composites towards ethanol oxidation reaction (EOR) in an alkaline medium was investigated using cyclic voltammetry (CV). CV analysis has shown that Pd/CB900 gave the least positive onset potential (Eonset = −0.587 ± 0.0065 V), highest electrochemically active surface area (EASA = 31.51 ± 2.24 m²·g−1), and highest anodic peak current density (If = 20.77 mA·cm−2) compared with Pd/CB800, Pd/CB1000, and Pd/C. Furthermore, the Tafel plot and chronoamperometry have shown that Pd/CB900 exhibited faster kinetics (Tafel slope = 297.6 ± 4.62 mV·dec−1) and durability (% current retention = 50.64 ± 2.99%) than Pd/C towards EOR in an alkaline medium. This study highlights the simple and straightforward synthesis of the anode electrocatalyst material for direct ethanol fuel cell application. [ABSTRACT FROM AUTHOR]

Effective and stable catalysts toward ethanol oxidation reaction (EOR) is very important for the application of direct ethanol fuel cells (DEFCs). This research reports a facile synthesis of Ni/sepiolite (Ni/SEP) catalyst through incipient wetness impregnation method, which has large amount of active sites and excellent electrochemical activity toward EOR. Through scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), nickel was found to distribute evenly on the fiber structure of sepiolite through ion exchange with the element magnesium without altering the main structure. With a geometric surface area of 0.07 cm2, Ni/SEP had a larger electrochemical surface area 0.44 m2 g−1, lower onset potential of 0.28 V (vs. SCE), higher peak current density (258.5 mA cm−2), and smaller Tafel slope (20 mV dec−1), indicating a superior electrochemical activity toward EOR. Within the experimental conditions, it was observed to be a diffusion-controlled process based on the linear relationship between peak current and root of scan rates, and the reaction could be accelerated by the increase of both C2H5OH and KOH concentrations. Through the study of cyclic voltammetry as well as calculation of apparent activation energy, an electrolytic-chemical (EC) reaction mechanism was suggested with high valence Ni species as the electron transfer carrier. [ABSTRACT FROM AUTHOR]

The development of highly active and cost‐effective electrocatalysts for the ethanol oxidation reaction (EOR) is imperative for the prospective application of direct ethanol fuel cells (DEFCs). In this study, we successfully synthesized porous octahedral nanoarchitectures comprising Pd, Rh, and Pt, through a straightforward one‐step co‐reduction aided by additional Ag precursors and other surface capping agents. The in‐situ galvanic replacement played a pivotal role in shaping hollow structures within the prepared PdRhPt porous octahedra, designated as PdRhPt‐POct. By strategically employing both composition and structure engineering, PdRhPt‐POct exhibited remarkably enhanced activity and stability toward EOR. Specifically, the mass activity of PdRhPt‐POct, reaching 8.11 A mg−1Pd+Pt, surpassed that of the majority of state‐of‐the‐art EOR electrocatalysts, owing to increased efficiency in C−C bond breaking and enhanced anti‐poisoning properties. This work introduces new prospects for designing and producing unique hollow‐structured multi‐metal nanocrystals as high‐performance EOR catalysts. [ABSTRACT FROM AUTHOR]

Improving the complete ethanol electrooxidation on Pd-based catalysts in alkaline media has drawn widely attention due to the high mass energy density. However, the weak adsorption energy of CH3CO* on Pd restricts the C-C bond cleavage. Inspired by the molecular orbital theory, we proposed the d-state-editing strategy to construct more unoccupied d-states of Pd for the enhanced interaction with CH3CO* to break C-C bonds. As expected, the reduced number of eg electrons and more unoccupied d-states of Pd successfully formed on as-prepared porous RhAu-PdCu nanosheets (PNSs). Theoretical calculations show that the optimized d-states of RhAu-PdCu PNS can effectively improve the adsorption of CH3CO* and drastically reduce the energy barrier of C-C bond cleavage, thus boosting the complete oxidation of ethanol. The charge ratio of C1 pathway on RhAu-PdCu PNSs is 51.5%, more than 2 times higher than that of Pd NSs. Our finding provides an innovative perspective for the design of highly-efficient noble-based electrocatalysts. [ABSTRACT FROM AUTHOR]

The fabrication of low-Pt loading and cost-efficient electrocatalysts still remains a challenge. In this work, a defective PtPd alloy with ultralow Pt content loaded on graphene (PtPd/G-40) is prepared by electrolytic synthesis method. During electrolysis, the formation of PtPd precursors and the exfoliation of graphite are achieved at the anode and cathode of the cell, respectively. The as-prepared PtPd/G-40 shows excellent electrocatalytic activity and stability toward hydrogen evolution reaction (HER) and ethanol oxidation reaction (EOR). Its mass activity is 29.7 times (at −100 mV) and 1.5 times higher than that of commercial Pt/C for HER and EOR, respectively. The ligand effect generated by formation of PtPd alloy and strain effect caused by abundant defects optimize the electronic structure of active Pt, which enhances its intrinsic activity and reduces the activation energy for HER and EOR. This facile synthetic approach generates a new type of graphene supporting defective metal alloy nanostructures as potential electrocatalysts for advanced energy conversion applications. [Display omitted] • Defective PtPd alloy with ultralow Pt content is produced by an electrolytic method. • The defective PtPd alloy on graphene shows superior electrocatalytic activity. • The impact of defective alloy on reaction intermediate adsorption is revealed. [ABSTRACT FROM AUTHOR]

Tin dioxide-modified Pt electrodes with different coverages ( θ SnO 2 ) were prepared by potentiostatically depositing tin on a Pt electrode in 0.1 M H2SO4 solutions containing various concentrations of SnCl2, followed by oxidizing in air. The θ SnO 2 was controlled by the SnCl2 concentration. The CO-stripping voltammogram of the Pt/SnO2 electrode with θ SnO 2 = 0.61 (Pt/SnO2(0.61)) exhibited two peaks, a prepeak due to the oxidation of adsorbed CO at Pt sites adjacent to SnO2 and a main peak due to that at Pt sites far from SnO2. In the kinetic analysis of both peaks using CO-stripping voltammograms at various sweep rates, the rate-determining steps for the prepeak and main peak were the coupling of adsorbed CO on Pt with OH on SnO2 surface by bifunctional effect and the dissociatively adsorption reaction of water to adsorbed OH on Pt, similar to the Pt electrode, respectively. In the linear sweep voltammograms of Pt/SnO2 electrodes in a (0.1 M HClO4 + 1 M ethanol) solution, the current for ethanol oxidation reaction (EOR) was the highest for θ SnO 2 = 0.61. The analysis of EOR products at different potentials for the Pt/SnO2(0.61) electrode by in situ infrared reflectance-absorption spectroscopy exhibited the Pt/SnO2(0.61) electrode facilitated acetic acid production. Moreover, rhodium was electrochemically deposited on the Pt sites adjacent to SnO2 using the limited CO-stripping technique. The area-controlled Rh deposition did not change the rate-determining steps of both peaks, but it not only enhanced EOR activity, but also decreased acetic acid selectivity and increased CO2 selectivity. [ABSTRACT FROM AUTHOR]

Abstract Direct ethanol fuel cells (DEFCs) play an indispensable role in the cyclic utilization of carbon resources due to its high volumetric energy density, high efficiency, and environmental benign character. However, owing to the chemically stable carbon‐carbon (C─C) bond of ethanol, its incomplete electrooxidation at the anode severely inhibits the energy and power density output of DEFCs. The efficiency of C─C bond cleaving on the state‐of‐the‐art Pt or Pd catalysts is reported as low as 7.5%. Recently, tremendous efforts are devoted to this field, and some effective strategies are put forward to facilitate the cleavage of the C─C bond. It is the right time to summarize the major breakthroughs in ethanol electrooxidation reaction. In this review, some optimization strategies including constructing core–shell nanostructure with alloying effect, doping other metal atoms in Pt and Pd catalysts, engineering composite catalyst with interface synergism, introducing cascade catalytic sites, and so on, are systematically summarized. In addition, the catalytic mechanism as well as the correlations between the catalyst structure and catalytic efficiency are further discussed. Finally, the prevailing limitations and feasible improvement directions for ethanol electrooxidation are proposed.

In the face of environmental pollution and an energy shortage, how to reduce the cost of a noble metal catalyst in clean energy such as the fuel cell system and improve its electrocatalytic performance is one of the hot issues in this field. Here, a facile stepwise co-reduction route for synthesizing a series of PdFe/Cu catalysts with surface reconstruction is investigated and the ethanol oxidation reaction (EOR) performance is explored. The greater exposure of Pd active sites makes it excellent in EOR in alkaline media compared to the homemade and commercial Pd black catalyst. The mass activity of PdFe/Cu (794.97 mA mg−1Pd) is 2.52 times that of the Pd black catalyst (315.64 mA mg−1Pd). This kind of PdFe/Cu catalyst shows enhanced mass current density (255.66 mA mg−1Pd) after the 1800 s chronoamperometry test and only exhibits a decay of 1.4% after accelerated 500-cycle measurement. The enhanced EOR performance may be due to the change in the electronic structure of Pd caused by synergistic and strain effects among Pd, Fe, and Cu. This work provides an effective and kindly strategy to synthesize electrocatalysts with superior activity and durability in relation to EOR.

A series of PdAu nanospheres with wrinkled-surface are synthesized as efficient electrocatalysts for ethylene glycol and ethanol oxidation reactions. [Display omitted] • The universal and simple method of 3D Pd-based nanospheres with novel morphology are studied. • The introduction of Au effectively modifies the electronic structure of Pd. • The content of Au plays a key role in enhancing the electrocatalytic performances of PdAu NSs. • The superior electrocatalytic performances of PdAu NSs to EGOR and EOR were effectively confirmed compared to commercial Pd/C. Three dimensional (3D) noble-metal nanomaterials with special surface structures have been regarded as high-performance catalysts for alcohol oxidation on account of their superior thermal stability, electrical conductivity and large specific surface area. Although extensive efforts have been devoted to the preparation of 3D Pd-based catalysts with superior activity and stability, designing a simple, effective and eco-friendly method remains a challenge. Herein, we developed a facile one-step coreduction strategy to synthesize a series of 3D surface-wrinkled PdAu nanospheres (NSs) with tunable Pd/Au atomic ratios and found a universal method to prepare surface-wrinkled PdM (M = Au, Pt, Cu and Pb) NSs. Benefiting from the function of the surfactant cetyltrimethylammonium chloride (CTAC), the synthesized PdAu NSs with different composition possess abundant surface wrinkles, which is beneficial for exposing more electroactive centers. Attributed to the unique geometric morphology and optimized atomic ratio, the PdAu-2 NSs exhibited an optimal mass activity (MA) of 8103 mA mg−1 and 5113 mA mg−1 for the ethylene glycol oxidation reaction (EGOR) and ethanol oxidation reaction (EOR), which was 6.1 and 4.1 times that of commercial Pd/C, respectively. Moreover, the PdAu-2 NSs exhibited superb stability after long-term current–time (i-t) and cyclic voltammetry (CV) tests of the EGOR and EOR. This work not only provides new avenues to engineer PdAu NSs with enhanced electrocatalytic performance but also offers guidance for extending to more 3D PdM (M = other metals) NSs with novel morphology applied to fuel cell fields. [ABSTRACT FROM AUTHOR]

Ethanol oxidation reaction (EOR) is a promising substituent to the conventional oxygen evolution reaction (OER) for highly active and energy-saving hydrogen production. The rational design of bifunctional electrocatalysts to achieve ethanol-assisted water splitting is important, but still maintains challenge. Herein, we successfully synthesize a tungsten (W) doped cobalt molybdate nanosheet arrays on porous copper foam by one-step hydrothermal method (W–CoMoO 4 /CF). The synthesized W–CoMoO 4 /CF shows the morphology of neatly stacked cobblestone nanosheets with high surface area and improved reaction kinetics, leading to substantial bifunctional catalytic activity for EOR/hydrogen evolution reactions (HER). To reach a current density of 100 mA cm−2, only an overpotential of 102 mV is demanded when using W–CoMoO 4 /CF as an electrode for HER, while a potential of 1.40 V is required for EOR. Moreover, the ethanol-assisted water electrolyzer is constructed by using W–CoMoO 4 /CF as both anode/cathode, which requires a small total voltage of 1.54 V to achieve 100 mA cm−2 and could run steadily for 12 h, revealing its excellent application prospects. This study provides a promising guidance for the development of high-valence metal modified bimetallic oxides for hydrogen generation. A tungsten (W) doped cobalt molybdate nanosheet arrays is designed as bifunctional electrocatalyst for EOR and HER. The ethanol-assisted water electrolyzer delivers a small voltage of 1.54 V at 100 mA cm−2 and high stability for the generation of hydrogen fuel. [Display omitted] • The W element is successfully doped into the CoMoO 4 material by a simple one-step strategy. • The high surface area and improved reaction kinetics endow excellent bifunctional activity. • The ethanol-assisted water electrolyzer based on W–CoMoO 4 /CF exhibits small cell voltage and high stability. • The coupling effect of HER/EOR improved the generation rate of hydrogen fuel. [ABSTRACT FROM AUTHOR]

The design of efficient and sustainable platinum-based catalysts is the key to developing direct alcohol fuel cells. Here, we designed highly open, one-dimensional Pt–Ni architectures with controllable wall thickness by selectively etching Pt–Ni nanowires. Pt atoms of both the inner and outer Pt–Ni architectures can participate in the electrochemical process, dramatically increasing the number of active sites and resulting in excellent alcohol electrooxidation performance. The obtained Pt1Ni5-M architecture with an ultrathin wall of 1.18 nm and a more open structure shows the best performance. The methanol oxidation reaction and ethanol oxidation reaction mass activities of Pt 1 Ni 5 -M are 7.4 (1.93 A/mg Pt) and 4.6 (0.96 A/mg Pt) times higher than that of Pt/C, respectively. After 3600s chronoamperometry tests, these Pt–Ni architectures also show improved durability with limited decay. This simple strategy inspires us to create more suitable catalysts with open structures for direct alcohol fuel cells. One-dimensional porous PtNi architectures with controllable wall thickness, particularly Pt 1 Ni 5 -M with subnanometer walls, significantly boosted platinum atom utilization, resulting in excellent alcohol oxidation performance. [Display omitted] • A novel porous one-dimensional PtNi architecture with controllable wall thickness and high openness was designed. • The wall thickness of Pt 1 Ni 5 -M can be controlled in a sub-nanometer range. • PtNi architectures greatly improve the utilization rate of Pt atoms and increase alcohol electrooxidation activity. • The alcohol electrooxidation activity trends of Pt 1 Ni x -M catalysts were negatively correlated with the wall thickness. [ABSTRACT FROM AUTHOR]

Pt-Sn/C has been widely reported as an anode catalyst in direct ethanol fuel cell (DEFC). However, this bimetallic catalyst often results in the production of a four-electron reaction product (acetate) instead of 12 electrons required for complete ethanol oxidation. In this work, a surfactant-free bromide anion exchange (BAE) method was used for the first time to prepare rare-earth (La, Ce, Pr, and Eu) modified Pt-Sn electrocatalysts for promoting the C-C bond cleavage. Among the synthesized nanomaterials, Pt-Sn-Ce/C exhibited the highest current density and good stability in alkaline medium. X-ray photoelectron spectroscopy (XPS) was used to analyze the surface properties of the synthesized materials and correlate them with electrochemical characterizations to enhance their activity towards ethanol oxidation reaction (EOR). The in situ Fourier transform infrared (FTIR) spectroscopy investigations provided evidence of similar EOR pathways for Pt-Sn and rare-earth modified bimetallic anodes. The presence of the cocatalysts promoted higher current density during the EOR, especially for Pt-Sn-Ce/C. [ABSTRACT FROM AUTHOR]

The Electrochemical Ethanol Oxidation Reaction (EOR) plays a pivotal role in next‐generation energy conversion devices. A clear understanding of the EOR reaction mechanism is critical for rational catalyst design, a task complicated by the numerous reaction intermediates and pathways involved. To this end, in situ Raman spectroscopy has proven invaluable in identifying many such intermediates at the electrode/electrolyte interface under varying applied potentials. Therefore, this technique allows for inference of the reaction mechanism based on the detected Raman signals of intermediates and observed structural changes, positioning in situ Raman spectroscopy as one of the most suitable methods for studying the EOR reaction mechanism. In this short review, with an eye towards future applications, we concentrate on the essential fundamentals of EOR and highlight recent advancements in understanding the EOR mechanism by in situ Raman spectroscopy. [ABSTRACT FROM AUTHOR]

An organic surfactant/stabilizer plays a critical role in synthesizing small and well-dispersed nanoparticles with large catalytic surface areas. However, a stabilizer typically interferes with the catalytic reaction by forming organic layers on the surface of nanoparticles. Here, we report that the role of a stabilizer can be replaced by the periodic and uniform fluid shear of Taylor vortex flow. Small, well-dispersed PdAg alloy nanoparticles on carbon were synthesized in the continuous Couette-Taylor (CT) reactor in the absence of a stabilizer. The synthesized PdAg nanoparticles (Pd64Ag36/C) showed two times higher mass activity than commercial Pd/C and good stability (retained 33% after 3,600 s) toward the electrochemical ethanol oxidation reaction due to their clean surface and alloy structure. [ABSTRACT FROM AUTHOR]

The preparation of electrocatalysts with high performance for the ethanol oxidation reaction is vital for the large-scale commercialization of direct ethanol fuel cells. Here, we successfully synthesized a high-performance electrocatalyst of a AuPd alloy with a decreased alloying degree via pulsed laser irradiation in liquids. As indicated by the experimental results, the photochemical effect-induced surficial deposition of Pd atoms, combined with the photothermal effect-induced interdiffusion of Au and Pd atoms, resulted in the formation of AuPd alloys with a decreased alloying degree. Structural characterization reveals that L-AuPd exhibits a lower degree of alloying compared to C-AuPd prepared via the conventional co-reduction method. This distinct structure endows L-AuPd with outstanding catalytic activity and stability in EOR, achieving mass and specific activities as high as 16.01 A mgPd−1 and 20.69 mA cm−2, 9.1 and 5.2 times than that of the commercial Pd/C respectively. Furthermore, L-AuPd retains 90.1% of its initial mass activity after 300 cycles. This work offers guidance for laser-assisted fabrication of efficient Pd-based catalysts in EOR.

Abstract The Electrochemical Ethanol Oxidation Reaction (EOR) plays a pivotal role in next‐generation energy conversion devices. A clear understanding of the EOR reaction mechanism is critical for rational catalyst design, a task complicated by the numerous reaction intermediates and pathways involved. To this end, in situ Raman spectroscopy has proven invaluable in identifying many such intermediates at the electrode/electrolyte interface under varying applied potentials. Therefore, this technique allows for inference of the reaction mechanism based on the detected Raman signals of intermediates and observed structural changes, positioning in situ Raman spectroscopy as one of the most suitable methods for studying the EOR reaction mechanism. In this short review, with an eye towards future applications, we concentrate on the essential fundamentals of EOR and highlight recent advancements in understanding the EOR mechanism by in situ Raman spectroscopy.

A conductive polymer-supported electrocatalyst in the form of fibrous mat has been developed that can be employed as a polymer-based electrode for direct ethanol fuel cells (DEFCs) with promoting effects to the state-of-the art Pd based catalysts. A series of conductive polyaniline (PANI)-containing polymer fibres-supported Pd electrocatalytic electrodes were successfully prepared and tested for the ethanol electro-oxidation reaction (EOR) in alkaline medium. The polymer support was a robust fibrous mat, where the fibres possessed a core-shell configuration. The core part was produced via electrospinning using a mixture of polyacrylonitrile (PAN) and 1-butyl-3-methylimidazolium chloride [BMIm]Cl ionic liquid (IL). The shell was a PANI layer deposited via the chemical polymerisation of aniline monomer. Pd was then electrodeposited on the fibres and the catalysts were tested for the EOR via cyclic voltammetry (CV) in a half-cell configuration and in a temperature range between 25 and 60 °C. The activity of the catalysts tested was measured in terms of activation energy and forward peak current density in the CV and compared to that of glassy carbon (GC)-supported Pd/PANI/PAN/IL fibrous catalysts. The polymer fibre-catalyst samples showed a higher active surface area and significantly lower activation energy than the GC-based ones. Even though the GC-supported catalysts showed a higher activity in terms of current, the Pd/(PAN/IL)-core/PANI-shell fibrous mats were active as well and, in some cases, demonstrated a promoting effect of PANI on Pd for EOR and a much better stability and robustness compared to the former. Furthermore, a series of promoting metals were investigated for these mats, such as Ag, Bi and Cu, with Ag and Bi demonstrating promoting effects compared to monometallic Pd/(PAN/IL)-core/PANI-shell mats in terms of both activation energy and peak current density. This work demonstrates a promising strategy in the arena of development of polymeric mats as anode electrodes for DEFCs, exploiting the benefits of PANI in terms of ease of synthesis, catalyst poisoning prevention, cost and promoting effects.

The Rh-based catalyst can effectively catalyze the cleavage of the C―C bond in ethanol, which is beneficial for achieving complete electro-oxidation of ethanol. However, the catalytic activity of Rh catalyst for ethanol electro-oxidation is low. In this study, Rh@Pt/C core-shell catalysts with concave cubic morphology are prepared by seed-mediated growth method. The catalytic performance of Rh@Pt/C core-shell catalysts with different Pt shell thicknesses in alkaline medium for ethanol electro-oxidation reaction (EOR) is investigated. The Rh@Pt0. 25/C core-shell catalyst has the highest mass normalized current for EOR of 520 mA/mg, and the area normalized current is also the highest at 0. 16 mA/cm2. The study shows that the surface strain effect and electronic ligand effect between Rh and Pt in Rh@Pt/C core-shell catalysts depend on the thickness of Pt shell on Rh surface, and the change of Pt shell thickness can regulate the synergistic effect of Rh and Pt in the catalyst, thereby reducing the adsorption of toxic intermediates on the catalyst surface and optimizing the performance of the catalyst for EOR. Overall, Rh@Pt0. 25/C core-shell catalyst with 3 layers of Pt shell on Rh surface exhibits the best EOR activity and stability, and the catalyst's resistance to poisoning is also excellent. [ABSTRACT FROM AUTHOR]