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Palladium nanosheets (Pd NSs) are widely used as electrocatalysts due to their high atomic utilization efficiency, and long-term stability. Here, the electronic structure modulation of the Pd NSs is realized by a femtosecond laser irradiation strategy. Experimental results indicate that laser irradiation induces the variation in the atomic structures and the macrostrain effects in the Pd NSs. The electronic structure of Pd NSs is modulated by laser irradiation through the balancing between Au-Pd charge transfer and the macros-strain effects. Finite element analysis (FEA) indicates that the lattice of the nanostructures undergoes fast heating and cooling during laser irradiation. The structural evolution mechanism is disclosed by a combined FEA and molecule dynamics (MD) simulation. These results coincide well with the experimental results. The L-AuPd NSs exhibit excellent mass activity and specific activity of 7.44 A mg-1 Pd and 18.70 mA cm-2 toward ethanol oxidation reaction (EOR), 4.3 and 4.4 times higher than the commercial Pd/C. The 2500-cycle accelerated durability (ADT) test confirms the outstanding catalytic stability of the L-AuPd NSs. Density functional theory (DFT) calculations reveal the catalytic mechanism. This unique strategy provides a new pathway to design the ultrathin nanosheet-based materials with excellent performance.

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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.

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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.

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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.

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The ethanol oxidation process in fuel cells is most efficient when conducted by platinum based catalysts. Our research team endeavored to find affordable and efficient catalysts, synthesizing catalysts based on metal oxides of nickel and molybdenum in the form of NiO/MoO2and NiO/MoO2hybridized with activated carbon obtained from the wheat husk (ACWH) through a hydrothermal method. After precise physical characterization, the capability of these catalysts in the ethanol oxidation process was measured through electrochemical analyses in an alkaline environment. The presence of ACWH in the catalyst structure significantly improves the active surface and electrocatalytic activity. NiO/MoO2/ACWH with a current density of 16 mA cm-2at a peak potential of 0.55 V and 93% cyclic stability after 5000 alternate CV cycles, can be an appealing, relatively efficient, and stable option in ethanol oxidation.

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The development of active and selective metal electrocatalysts for complete ethanol oxidation reaction (EOR) into desired C1 products is extremely promising for practical application of direct ethanol fuel cells. Despite some encouraging achievements, their activity and selectivity remain unsatisfactory. In this work, it is reported that 2D PtRhPb mesoporous nanosheets (MNSs) with anisotropic structure and surface-clean metal site perform perfectly for complete EOR electrocatalysis in both three-electrode and two-electrode systems. Different to the traditional routes, a selective etching strategy is developed to produce surface-clean mesopores while retaining parent anisotropy quasi-single-crystalline structure without the mesopore-forming surfactants. This method also allows the general synthesis of surface-clean mesoporous metals with other compositions and structures. When being performed for alkaline EOR electrocatalysis, the best PtRhPb MNSs deliver remarkably high activity (7.8 A mg-1) and superior C1 product selectivity (70% of Faradaic efficiency), both of which are much better than reported electrocatalysts. High performance is assigned to multiple structural and compositional synergies that not only stabilized key OHads intermediate by surface-clean mesopores but also separated the chemisorption of two carbons in ethanol by adjacent Pt and Rh sites, which facilitate the oxidation cleavage of stable C─C bond for complete EOR electrocatalysis.

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In this study, wine lees and waste activated sludge (WAS) were co-fermented for the first time in a 4:1 ratio (COD basis) at 20, 40, 70 and 100 gCOD/L, in batch at 37 °C and pH 7.0. The substrates were successfully converted to caproate (C6) and heptanoate (C7) with a high selectivity (40.2 % at 40 gCOD/L). The rapidly-growing chain-elongating microbiome was enriched inClostridiaceaeandOscillospiraceae, representing together 3.4-8.8 % of the community. Substrate concentrations higher than 40 gCOD/L negatively affected C6 and C7 selectivities and yields, probably due to microbial inhibition by high ethanol concentrations (15.82-22.93 g/L). At 70 and 100 gCOD/L, chain elongation shifted from ethanol-based to lactate-based, with a microbiome enriched in the lactic acid bacteriaRoseburia intestinalis(27.3 %) andEnterococcus hirae(13.8 %). The partial pressure of H2(pH2) was identified by thermodynamic analysis as a fundamental parameter for controlling ethanol oxidation and improving C6 and C7 selectivities.

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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.

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As a novel electrochemical energy conversion device, direct ethanol fuel cells are currently encountering two significant challenges: CO poisoning and the difficulty of C-C bond cleavage in ethanol. In this work, an amorphous PdS nanowires/ultrafine IrMnOx bimetallic oxides (denoted as a-PdS/IrMnOx NWs) catalyst with abundant oxide/metal (crystalline/amorphous) inverse heterogeneous interfaces was synthesized via a hydrothermal process succeeded by a nonthermal air-plasma treatment. This unique interfacial electronic structure along with the incorporation of oxyphilic metal has resulted in a significant enhancement in the electrocatalytic performance of a-PdS/IrMnOx NWs toward the ethanol oxidation reaction, achieving current densities of 12.45 mA·cm-2 and 3.68 A·mgPd-1. Moreover, the C1 pathway selectivity for ethanol oxidation has been elevated to 47%, exceeding that of other as-prepared Pd-based counterparts and commercial Pd/C catalysts. Density functional theory calculations have validated the findings that the decoration of IrMn species onto the amorphous PdS surface has induced a charge redistribution in the interface region. The redistribution of surface charges on the a-PdS/IrMnOx NWs catalyst results in a significant decrease in the activation energy required for C-C bond cleavage and a notable weakening of the CO binding strength at the Pd active sites. Consequently, it enhanced both the EOR C1 pathway selectivity and CO poisoning resistance to the a-PdS/IrMnOx NWs catalyst.

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Noble metal nanocrystals face challenges in effectively catalyzing electrochemical ethanol oxidation reaction (EOR)-represented multistep, multielectron transfer processes due to the linear scaling relationship among binding energies of intermediates, impeding independent optimization of individual elemental steps. Herein, we develop noble metal nanocrystals with a range of local surface binding affinities in close proximity to overcome this challenge. Experimentally, this is demonstrated by applying tensile strain to a Pd surface and decorating it with discrete Au atoms, forming a diversity of binding sites with varying affinities in close proximity for guest molecules, as evidenced by CO probing and density functional theory calculations. Such a surface enables reaction intermediates to migrate between different binding sites as needed for each elemental step, thereby reducing the energy barrier for the overall EOR when compared to reactions at a single site. On these tailored surfaces, we attain specific and mass activities of 32.7 mA cm-2 and 47.8 A mgPd-1 in EOR, surpassing commercial Pd/C by 10.9 and 43.8 times, respectively, and outperforming state-of-the-art Pd-based catalysts. These results highlight the promise of this approach in improving a variety of multistep, multielectron transfer reactions, which are crucial for energy conversion applications.

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Carbon dioxide (CO2) plays a crucial role in carbon chain elongation with ethanol serving as an electron donor. In this study, the impacts of various carbonates on CO2 concentration, hexanoic acid production, and microbial communities during ethanol-butyric acid fermentation were explored. The results showed that the addition of MgCO3 provided sustained inorganic carbon and facilitated interspecific electron transfer, thereby increasing hexanoic acid yield by 58%. MgCO3 and NH4HCO3 inhibited the excessive ethanol oxidation and decreased the yield of acetic acid by 51% and 42%, respectively. The yields of hexanoic acid and acetic acid in the CaCO3 group increased by 19% and 15%, respectively. The NaHCO3 group exhibited high headspace CO2 concentration, promoting acetogenic bacteria enrichment while reducing the abundance of Clostridium_sensu_stricto_12. The batch addition of NaHCO3 accelerated the synthesis of hexanoic acid and increased its production by 26%. The relative abundance of Clostridium_sensus_stricto_12 was positively correlated with hexanoic acid production.

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Designing and synthesizing one-dimensional porous Pt nanocrystals with unique optical, electrocatalytic, and theranostic properties are gaining lots of attention, especially to overcome the challenges of tumor recurrence and resistance to platinum-based chemotherapy. Herein, we represented an interesting report of a one-step and facile strategy for synthesizing multifunctional one-dimensional (1D) porous Pt nanoribbons (PtNRBs) with highly efficient therapeutic effects on cancer cells based on inherent electrocatalytic activity. The critical point in the formation of luminescent porous PtNRBs was the use of human hemoglobin (Hb) as a shape-regulating, stabilizing, and reducing agent with facet-specific domains on which fluorescent platinum nanoclusters at first are aggregated by aggregation-induced emission phenomena (AIE) and then crystallized into contact and penetration twins, as intermediate products, followed by shaping of the final luminescent porous ribbon nanomaterials, owing to oriented attachment association via the Ostwald ripening mechanism. From a medical point of view, the key strategy for effective cancer therapy occured via using low-dosage ethanol in the presence of electroactive porous PtNRBs based on intracellular ethanol oxidation-mediated reactive oxygen species (ROS) generation. The role of heme groups of Hb, as electrocatalytically active centers, was successfully demonstrated in both kinetically controlled anisotropic growth of NRBs for slowing down the reduction of Pt(II) followed by oligomerization of Pt(II)-Hb complexes via platinophilic interactions as well as electrocatalytic ethanol oxidation for therapy. Interestingly, hyaluronic acid-targeted (HA) Hb-PtNRB in the presence of low-dose ethanol caused extraordinary arrest of tumor growth and metastasis with no recurrence even after the treatment course stopped, which caused elongation of tumor-bearing mice survival. HA/Hb-PtNRB was completely biocompatible and exhibited high tumor-targeting efficacy for fluorescent imaging of breast tumors. Therefore, the synergistic electrocatalytic activity of PtNRBs is presented as an efficient and safe cancer theranostic method for the first time.

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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.

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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.

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Integrating more than one type of metal into a nanoparticle that has a well-defined morphology and composition expands the functionalities of nanocatalysts. For a metal core/porous multimetallic shell nanoparticle, the availability of catalytically active surface sites and molecular mass transport can be enhanced, and the multielemental synergy can facilitate intraparticle charge transport. In this work, a reliable and robust synthesis of such a functional tetrametallic nanoparticle type is presented, where a micro- and mesoporous PdPtIr shell is grown on Au nanorods. The effect of critical synthesis parameters, namely temperature and the addition of HCl are investigated on the hydrodynamic size of the micellar pore template as well as on the stability of the metal chloride complexes and various elemental analysis techniques prove composition of the porous multimetallic shell. Due to the synergistic properties, the tetrametallic nanorods possess extensive negative surface charge making them a promising catalyst in reduction reactions. Dye degradation as well as the conversion of p-nitrophenol to p-aminophenol is catalyzed by the supportless nanorods without light illumination. By depositing the particles onto conductive substrates, the nanostructured electrodes show promising electrocatalytic activity in ethanol oxidation reaction. The nanocatalyst presents excellent morphological stability during all the catalytic test reactions.

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Spin engineering is a promising way to modulate the interaction between the metal d-orbital and the intermediates and thus enhance the catalytic kinetics. Herein, an innovative strategy is reported to modulate the spin state of Co by regulating its coordinating environment. o-c-CoSe2-Ni is prepared as pre-catalyst, then in situ electrochemical impedance spectroscopy (EIS) and in situ Raman spectroscopy are employed to prove phase transition, and CoOOH/Co3O4 is formed on the surface as active sites. In hybrid water electrolysis, the voltage has a negative shift, and in zinc-ethanol-air battery, the charging voltage is lowered and the cycling stability is greatly increased. Coordinated atom substitution and crystalline symmetry change are combined to regulate the absorption ability of reaction intermediates with balanced optimal adsorption. Coordinated atom substitution weakens the adsorption while the crystalline symmetry change strengthens the adsorption. Importantly, the tetrahedral sites are introduced by Ni doping which enables the co-existence of four-coordinated sites and six-coordination sites in o-c-CoSe2-Ni. The dz2 + dx2-y2 orbital occupancy decreases after the atomic substitution, while increases after replacing the CoSe6-Oh field with CoSe6-Oh/CoSe4-Td. This work explores a new direction for the preparation of efficient catalysts for water electrolysis and innovative zinc-ethanol-air battery.

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Unsatisfactory performance of ethanol oxidation reaction (EOR) catalysts hinders the application of direct ethanol fuel cells (DEFCs), while traditional alloy catalysts (like PdPt) is cursed by Sabatier principle due to countable active site types. However, bacterial soluble extracellular polymeric substances (s-EPS) owning abundent functional groups may help breacking through it by contrusting different active sites on PdPt and inducing them to play synergy effect, which is called interface engineering. Using s-EPS to engineer catalysts is more green and consumes lower energy compared to chemical reagents. Herein, PdPt alloy nanoparticles (≈2.1 nm) are successfully in situ synthesized by/on s-EPS of Bacillus megaterium, an ex-holotype. Tryptophan residuals are proved as the main reductant. In EOR, PdPt@s-EPS shows higher activity (3.89 mA cm-2) than Pd@s-EPS, Pt@s-EPS, Pt/C and most reported akin catalysts. Its stability and durability are excellent, too. DFT modelling further demonstrates that, interface engineering by s-EPS breaks through Sabatier principle, by the synergy of diverse sites owning different degrees of d-p orbital hybridization. This work not only makes DEFCs closer to practice, but provides a facile and green strategy to design more catalysts.

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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.

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Due to the challenges involved in achieving high metal load, uniform metal dispersion and nanosized metal particles simultaneously, it is difficult to develop a simple protocol for the rapid and efficient synthesis of Pt-based composites for electrocatalytic ethanol oxidation reaction (EOR). In this study, a facile ultrafast thermal shock strategy via Joule heating was applied to fabricate a series of PtCoCu ternary nanoalloys decorated carbon nanotube composites (TS-PtCoCu/CNTs), without the need for a reducing agent or surfactant. The TS-PtCoCu/CNTs with optimal Pt content (∼15 %) exhibited excellent EOR activity, with mass and specific activity of 3.58 A mgPt-1 and 5.79 mA cm-2, respectively, which are 3.8 and 13.5 times higher than those of Pt/C. Compared with the control prepared through the traditional furnace annealing, the catalyst also showed excellent activity and stability. DFT calculations revealed that the TS-PtCoCu/CNTs possesses a downshifted d-band center, weakened CO adsorption and higher OH affinity compared with monometallic Pt, all of which lead to the preferred C1 pathway for EOR. This study demonstrates an ultrafast construction of a highly efficient Pt-Co-Cu ternary catalyst for EOR. Additionally, it provides insights into the reaction mechanism based on structural characterization, electrochemical characterization, and theoretical calculations.

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Electrochemical ethanol oxidation is crucial to directly convert a biorenewable liquid fuel with high energy density into electrical energy, but it remains an inefficient reaction even with the best catalysts. To boost ethanol oxidation, developing multimetallic nanoalloy has emerged as one of the most effective strategies, yet faces a challenge in the rational engineering of multimetallic active-site ensembles at atomic-level. Herein, starting from typical PtCu nanocrystals, an atomic Sn diffusion strategy is developed to construct well-defined Pt47Sn12Cu41 octopod nanoframes, which is enclosed by high-index facets of n (111)-(111), such as {331} and {221}. Pt47Sn12Cu41 achieves a high mass activity of 3.10 A mg-1 Pt and promotes the C-C bond breaking and oxidation of poisonous CO intermediate, representing a state-of-the-art electrocatalyst toward ethanol oxidation in acidic electrolyte. Density functional theory （DFT） calculations have confirmed that the introduction of Sn improves the electroactivity by uplifting the d-band center through the s-p-d coupling. Meanwhile, the strong binding of ethanol and the reduced energy barrier of CO oxidation guarantee a highly efficient ethanol oxidation process with improved Faradic efficiency of C1 products. This work offers a promising strategy for constructing novel multimetallic nanoalloys tailored by atomic metal sites as the efficient electrocatalysts.