Efficient Ethanol Research Articles

Unconventional s-p-d hybridization in modulating frontier orbitals of carbonaceous radicals on PdBi nanosheets for efficient ethanol electrooxidation

Rational design of highly efficient ethanol electrooxidation catalysts requires modulation of their band structure, yet most of the understanding stops at either upshift or downshift of d-band center that facilitates only a portion of ethanol oxidation reaction (EOR) process. Herein, we take in-situ formed carbonaceous intermediates as an essential part in regulating the band structure of 2D catalysts for the whole EOR process. We found that, by alloying Bi into Pd nanosheets, d band of Pd upshifted, resulting in the enhanced adsorption ability of the catalyst. After the adsorption of CH3CH2OH, p band of Bi dragged down d-band of Pd and lifted up s and p orbitals of the adsorbed carbonaceous radicals, forming molecular orbitals that bridged their energy gaps and lowered the energy barriers of electron transfer in C1 pathway. This unconventional s-p-d hybridization offers Pd14.9Bi nanosheets exhibit high mass activity of 6.6 A/mgpd and C1 selectivity of 19.7 %.

Pentose-Fermenting Yeasts in Nature: Ecology, Biodiversity and Applications

The world’s energy sector has undergone drastic changes in the last decades due to the climate change and the turn to renewable energy sources. Biomass is the largest renewable source of carbohydrates on the Earth and is an important substrate for biofuel production. Saccharomyces cerevisiae yeasts are the main producer of first-generation ethanol from corn and sugarcane. However, these yeasts lack the ability to utilize the important components of lignocelluloses such as pentoses D-xylose and L-arabinose. Pentose-fermenting yeasts could become an alternative to S. cerevisiae in ethanol production from lignocelluloses. This review focuses on the ecology, geographical distribution, taxonomy, and potential applications of naturally-occurring pentose-fermenting yeasts. Pentose-fermenting yeasts have been frequently found in the lignocelluloseassociated substrates. Decaying and rotten wood and the gut of wood-boring insects are especially important natural reservoirs of this group of yeasts. Simple sugars xylose and L-arabinose would be present in such habitats as suitable nutrients for pentose-assimilating yeasts. The other natural habitats reported for pentose-fermenting yeasts are soil, plants, and herbivore faeces. Pentose-fermenting yeasts are found in many geographical regions and have been isolated on almost each continent. Dozens of novel pentose-fermenting yeast species have been discovered in the last decade. The previously poorly explored regions, including Brazil, China, and several Asian countries were especially oft en reported as sites of isolation of such yeasts. Most xylose-fermenting yeasts belong to genera Scheffersomyces, Candida, Spathaspora, Sugiyamaella, and Pachysolen, while the most efficient ethanol producers are represented by species Scheffersomyces stipitis and Spathaspora passalidarum. The vast majority of research on the biotechnological application of pentose-fermenting yeasts focuses on their role in the production of bioethanol from lignocellulose. This group of yeasts could be either directly involved in the fermentation stage of ethanol production or serve as a source of genetic material for the genetic manipulation of other industrial yeast strains. Pentose-fermenting yeasts could also be involved in the production of various chemicals from lignocellulosic substrates, mainly polyols, xylitol, and arabitol. Thus, the search for novel pentose-fermenting yeasts that could become new efficient ethanol producers or donors of new genetic material is still ongoing. The previously unexplored or poorly studied geographical regions and natural habitats can hide many novel yeasts with huge biotechnological potential.

Hollow multi-shelled structural SnO2 with multiple spatial confinement for ethanol gas sensing

Ethanol gas sensing has been attracting more and more attention due to its significance, such as human health care, and detection in drunk driving. However, the low sensitivity, the high limit of detection and the long response time restrain its further application development. Here we report SnO2 nanomaterials with well-controlled hollow multi-shelled structure as an efficient ethanol gas sensing. The shell number was tuned by the concentration of the precursor. Among, the double-shell SnO2 nanomaterials (SnO2-D) exhibited the best selectivity towards ethanol, reaching 22.5 of Rg/Ra ratio. Moreover, the 1 ppm ethanol was even detected, the Rg/Ra ratio being 1.37. The response time to 100 ppm ethanol was only 2 s. Furthermore, the SnO2-D maintained the same performance after 21 days of continuous response to 100 ppm ethanol. Based on experiments and in situ FTIR, the outstanding sensing performance is attributed to the excellent spatial confinement and large active surface of the double-shell that combine the enhanced gas adsorption, and increase conductive electrons.

Cellulose hydrolysis and bioethanol production from various types of lignocellulosic biomass after microwave-assisted hydrotropic pretreatment

This study examined the impact of microwave-assisted hydrotropic pretreatment using sodium cumene sulfonate on the enzymatic hydrolysis of cellulose contained in pine chips, beech chips and wheat straw biomasses as well as the effectiveness of the production of bioethanol from the obtained hydrolysates. The effectiveness of enzymatic hydrolysis of cellulose contained in beech chips and wheat straw subjected to pretreatment in optimised process conditions amounted to ca. 55–60%. As a result of this, hydrolysates containing glucose in the concentration of 76–84 g/L were acquired, which is a significant achievement in the case of cellulosic hydrolysates. A lower efficiency of the process was recorded when cellulose from pine chips was used (maximum hydrolysis efficiency was 17.21 ± 0.09%), which confirms a higher resistance of softwood biomass to the process of biodegradation. The highest concentration of ethanol, at the level of 41.44 ± 0.55 g/L, was achieved through the fermentation of the medium being a hydrolysate of wheat straw after microwave-assisted hydrotropic pretreatment. The developed raw material and hydrolysate preparation method indicates the possibility of using wheat straw after microwave-assisted hydrotropic pretreatment for efficient cellulosic ethanol production using high-gravity (HG) technology.

Length-tunable Pd2Sn@Pt core-shell nanorods for enhanced ethanol electrooxidation with concurrent hydrogen production.

The electrooxidation of ethanol as an alternative to the oxygen evolution reaction presents a promising approach for low-cost hydrogen production. However, the design and synthesis of efficient ethanol oxidation electrocatalysts remain key challenges. Here, a colloidal procedure is developed to prepare Pd2Sn@Pt core-shell nanorods with an expanded Pt lattice and tunable length. The obtained Pd2Sn@Pt catalysts exhibit superior activity and stability for ethanol electrooxidation compared to Pd2Sn and commercial Pt/C catalysts. By tuning the length of the Pd2Sn@Pt nanorods, remarkable mass activity of up to 4.75 A mgPd+Pt-1 and specific activity of 20.14 mA cm-2 are achieved for the short nanorods owing to their large specific surface area. A hybrid electrolysis system for ethanol oxidation and hydrogen evolution is constructed using Pd2Sn@Pt as the anodic catalyst and Pt mesh as the cathode. The system requires a low cell voltage of 0.59 V for the simultaneous production of acetic acid and hydrogen at a current density of 10 mA cm-2. Density functional theory calculations further reveal that the strained Pt shell reduces energy barriers in the ethanol electrooxidation pathway, facilitating the conversion of ethanol to acetic acid. This work provides valuable guidance for developing highly efficient ethanol electrooxidation catalysts for integrated hydrogen production systems.

Lattice engineering of AuPd@Pt core–shell icosahedra for highly efficient electrocatalytic ethanol oxidation

Lattice engineering of AuPd@Pt core–shell icosahedra for the exploration of the mechanism of the ethanol oxidation reaction.

Small amounts of main group metal atoms matter: ultrathin Pd-based alloy nanowires enabling high activity and stability towards efficient oxygen reduction reaction and ethanol oxidation.

Proton-exchange membrane fuel cells are considered as promising energy-conversion devices. Alloying 3d transition metals with noble metals not only highly improves the performance of noble metal-based catalysts towards electrocatalytic reactions in fuel cells due to d-d hybridization interaction but also decreases the total cost. However, the rapid leaching of transition metal atoms leads to a fast decay of the activity, which seriously affects the performance of the fuel cell. Herein, alloyed Pd-main group metal (e.g. Pb, Bi, Sn) ultrathin nanowires were realized by a facile one-step wet-chemical strategy. The content of the main group metal could be tuned in a certain range while maintaining the same one-dimensional ultrathin nanowire morphology, which provided a large surface area and many more active sites. These Pd-based alloys showed a significant improvement in electrocatalytic activity and durability towards the oxygen reaction reaction as well as ethanol oxidation reaction. Optimal activity occurred when a small amount of main group metal existed, which could be explained through calculations by a strong p-d hybridization interaction between the main group metal and Pd to optimize the surface electronic structure collaboratively. Besides, high stability was achieved, which could be ascribed to the increased antioxidant activity of Pd by the main group metal. Furthermore, the low amount of the main group metal atoms also prevented them from leaching out of the crystal lattice.

Study on ethanol electro-oxidation over a carbon-supported Pt-Cu alloy catalyst by pinhole on-line electrochemical mass spectrometry.

A carbon supported Pt-Cu electrocatalyst was synthesized by the microwave-polyol method following acid-treatment and physically characterized by different techniques including X-ray diffraction (XRD) and transmission electron microscopy (TEM). Both potentiodynamic and potentiostatic measurements with pinhole on-line electrochemical mass spectrometry were carried out to study the electrocatalytic activity and reaction intermediates of Pt/C and Pt-Cu/C electrocatalysts during the ethanol oxidation reaction. The results of potentiodynamic and potentiostatic measurements showed that the Pt-Cu/C electrocatalyst has higher ethanol oxidation efficiency and incomplete ethanol oxidation to acetaldehyde and acetic acid prevails under the given conditions. After calibration of the m/z = 44 mass signal, the CO2 current efficiencies on Pt/C and PtCu-3/C were ∼7% and ∼12%, respectively, which reveal that the presence of copper enhances the complete ethanol oxidation to CO2.

Large Au@Pd/PdOx core–porous shell nanoparticles as efficient ethanol oxidation electrocatalysts

An ultrathin layer of PdOx on the surface of large Au@Pd core–porous shell nanoparticles with diameters of between 20 and 60 nm plays a significant role in electrochemical ethanol oxidation.

A covalency-aided electrochemical mechanism for CO2 reduction: the synergistic effect of copper and boron dual active sites drives the formation of a high-efficiency ethanol product.

Electrocatalytic carbon dioxide (CO2) conversion into high-value multi-carbon products is of great significance for CO2 utilization, but the chemical inertness, low yields, and poor product selectivity hinder the application prospects of the electrocatalytic conversion methods. In this work, a covalency-aided electrochemical mechanism for CO2 reduction is proposed for the first time by embedding the nonmetallic element boron (B) on copper surfaces, in which p-block dopants have a significant impact on modifying the adsorbent intermediates and improving the catalytic activity. Herein, B atoms not only provide empty and occupied orbitals to adsorb and activate CO, but also afford a large amount of charge to stabilize the C2 intermediates. In addition, B atoms can also adjust the oxidation state of nearby copper (namely, Cu+), and the synergistic Cu+ and B dual active sites act as O* adsorption and C* adsorption sites, respectively, leading to strong adsorption and activation of CO2. First-principles calculations reveal that CO2 can be reduced into C2H5OH with an ultralow potential of -0.26 V. Overall, this study provides new insights into CO2 reduction, which offers a promising way for achieving an efficient ethanol product.

A universal synthesis of ultrathin Pd-based nanorings for efficient ethanol electrooxidation.

Metallic nanorings (NRs) with open hollow structures are of particular interest in energy-related catalysis due to their unique features, which include the high utilization of active sites and facile accessibility for reactants. However, there is still a lack of general methods for synthesizing Pd-based multimetallic NRs with a high catalytic performance. Herein, we develop a template-directed strategy for the synthesis of ultrathin PdM (M = Bi, Sb, Pb, BiPb) NRs with a tunable size. Specifically, ultrathin Pd nanosheets (NSs) are used as a template to steer the deposition of M atoms and the interatomic diffusion between Pd and M, subsequently resulting in the hollow structured NRs. Taking the ethanol oxidation reaction (EOR) as a proof-of-concept application, the PdBi NRs deliver a substantially improved activity relative to the Pd NSs and commercial Pd/C catalysts, simultaneously showing outstanding stability and CO tolerance. Mechanistically, density functional theory (DFT) calculations disclose that the incorporation of Bi reduces the energy barrier of the rate-determining step in the EOR C2-path, which, together with the high ratio of exposed active sites, endows the PdBi NRs with an excellent EOR activity. We believe that our work can illuminate the general synthesis of multimetallic NRs and the rational design of advanced electrocatalysts.

Fabrication of dendritic PdCu alloy supported on 3D N-doped hollow graphene for efficient ethanol electrooxidation.

Fabricating highly efficient Pd-based nanocatalysts with a well-defined structure is desired for the commercialization of direct ethanol fuel cell (DEFC). Herein, a series of hierarchical three-dimensional N-doped hollow graphene spheres (NHGS) supported dendritic PdCu alloy catalysts PdxCu(d)-NHGS (x: Cu/Pd theoretical molar ratio of 4, 2, and 1) are assembled by one-pot ascorbic acid reduction-immobilization method. Aiming to maximize the Pd utilization and realize the efficient ethanol electrooxidation, this novel electrocatalyst offers potent activity sites and promotes electron and ion kinetics simultaneously. Characterization indicates that the as-obtained Pd4Cu(d) alloy nanoparticles with average sizes of approximately 55 nm are evenly dispersed on the NHGS supporting materials obtained by using the SiO2 nanospheres template strategy. Three catalysts all exhibit enhanced electrocatalytic activity, of which the Pd4Cu(d)-NHGS shows the highest mass current activity (2683 mA mgPd-1), which is 2.59 times of the commercial Pd/C toward ethanol electrooxidation in alkaline medium. Based on the results, we believed that the Pd4Cu(d)-NHGS could exhibit extensive application prospect in alkaline DEFC.

Local atomic structure order and electrochemical properties of NiO based nano-catalysts for ethanol sensing at room temperature

The increased emission of volatile organic compounds (VOCs) and their adverse effects on environment led to the development of more economical and sustainable sensing technologies. Ethanol is a member of VOC family and has harmful effect on human health and environment. Therefore, an efficient electrocatalyst for ethanol detection at ambient temperature is highly desirable. Here we present the successful synthesis of NiO based sensing material where modification of NiO was carried out by transition metals doping (8% Cu and 8% Zn) and codoping (4% Cu + 4% Zn). The synthesized catalysts were characterized by several techniques like powder X ray diffraction, Raman spectroscopy, scanning electron microscopy, X-ray absorption fine structure, Brunauer–Emmett–Teller and diffuse reflectance spectroscopy. The electrochemical responses showed that the codoped NiO has a better catalytic performance towards ethanol detection with a wide linear range from 3 mM to 12 mM, and a low detection limit (LOD) of 2.2 mM. The striking analytical performance and facile preparation technique make this catalyst effective for efficient enzyme-free electrochemical ethanol sensing.

Efficient ethanol electro-reforming on bimetallic anodes supported on adenine-based noble carbons: hydrogen production and value-added chemicals

Herein, adenine-derived noble carbons are used as anodic supports for PtRu nanoparticles for the ethanol oxidation reaction (EOR). Three noble carbons were synthesized using salt melts as templates and denoted as ANZ, ALZ and ALK depending on the precursor (LiCl/ZnCl2, NaCl/ZnCl2 and LiCl/KCl). Their large nitrogen content and pore volume (ANZ > ALZ > ALK) facilitate the formation of small PtRu nanoparticles (2–3 nm), while variations in the C/N ratio and surface area deeply affected the alloy formation (0–58%). In a half-cell configuration, PtRu/ANZ exhibited the highest activity (443 mA/mgPtRu), followed by PtRu/ALZ and PtRu/ALK, due its higher dispersion degree and lower alloying percentage. More interestingly, PtRu/ANZ and PtRu/ALZ presented 2.4 and 1.6 larger mass activity than commercial PtRu/C. Regarding the ethanol electrolysis, the best materials were scaled up to a proton exchange membrane cell. Acetaldehyde was the major compound followed by acetic acid and ethyl acetate (anode), while hydrogen was produced with 100% faradaic efficiency (cathode). PtRu/ANZ provided the best electrochemical performance, shifting the acetic acid production to a lower potential (0.6 V), requiring lower energy (∼35kWh/kgH2 at 1 A) than commercial water electrolyzers. These promising results set a precedent for high nitrogen containing supports for EOR electrocatalysts.

Ethanol Production through Optimized Alkaline Pretreated Elaeis guineensis Frond Waste from Krabi Province, Thailand

Oil palm frond as an abundant and inexpensive lignocellulosic waste was used to optimize alkaline pretreatment for ethanol production. The studied lignocellulosic waste is one of the largest biomasses (47%) in oil palm waste. Oil palm frond fibers were processed by steam explosion, hot water extraction, and alkaline extraction pretreatment, followed by simultaneous saccharification and fermentation (SSF), for ethanol production as an alternative energy resource. To optimize alkaline extraction for oil palm frond, a Taguchi method with a three-factor design constituted a concentration of NaOH (15%, 20%, and 25%), time (30, 60, and 90 min), and temperature (70, 80, and 90 °C). An optimum alkaline extraction condition of 15% NaOH at 90 °C for 60 min gave the highest percentage of α-cellulose (80.74%) and the lowest percentages of lignin (15.99%), ash (1.05%), and pentosan (2.09%). In addition, the optimized pretreatment condition significantly improved α-cellulose to 52.65% and removed lignin up to 51.78%. Simultaneous saccharification and fermentation (SSF) was carried out with 10% (dry weight) alkaline pretreated OPF fibers, Celluclast 1.5 L (15 FU/gram substrate), Novozyme 188 (15 IU/gram substrate), and Saccharomyces cerevisiae SC90 at 40 and 45 °C. The highest ethanol concentration, theoretical ethanol yield, and ethanol productivity observed at 40 °C were 33.15 g/L, 72.54%, and 0.55 g/L/h, respectively. The results suggest that an optimized alkaline pretreatment process using palm frond as a lignocellulosic waste is a sustainable approach to produce efficient ethanol production.

Intermetallic Pd3Pb nanobranches with low-coordinated surface atoms for highly efficient ethanol oxidation reaction

Pd based bimetallic nanocrystals (NCs) with low-coordinated surface atoms endow a tremendous ability to modify electronic properties and have the synergistic effect to improve electrocatalytic performance. Among various bimetallic NCs with different compositions, intermetallic Pd-Pb NCs can improve the poisoning tolerance of surface active sites during electrocatalytic reactions. In addition, Pb can provide abundant oxygen-containing species (OHads) and has the ability to cleavage the C–C bond during electrocatalysis that can hinder the production of COads intermediate species, thereby improving ethanol oxidation reaction (EOR) performance. Herein, we report a wet-chemical method for synthesizing highly uniform Pd3Pb nanobranches (NBs). The growth process of Pd3Pb NBs was controlled using ascorbic acid as a reductant, oleylamine as a solvent, 1-octadecene as a surfactant, and ammonium bromide as a shape-directing agent. Their unique NB morphology makes them suitable as electrocatalysts, attributed to the effective adsorption of ethanol and (OH)ads and enhanced removal capability of intermediates adsorbed on the active site of Pd3Pb NBs due to the intermetallic Pd–Pb composition and high density of low-coordinated surface atoms in Pd3Pb branches that can enhance EOR in alkaline media. The prepared Pd3Pb NBs exhibited significantly higher mass activity than Pd3Pb nanocubes and commercial Pd/C catalysts.

A chiral porous organic polymer COP-1 used as stationary phase for HPLC enantioseparation under normal-phase and reversed-phase conditions.

A spherical chiral porous organic polymer (POPs) COP-1 is synthesized by the Friedel-Crafts alkylation reaction of Boc-3-(4-biphenyl)-L-alanine (BBLA) and 4,4'-bis(chloromethyl)-1,1'-biphenyl (BCMBP), which was used as a novel chiral stationary phase (CSPs) for mixed-mode high-performance liquid chromatography (HPLC) enantioseparation. The racemic compounds were resolved in normal-phase liquid chromatography (NPLC) using n-hexane/isopropanol as mobile phase and reversed-phase liquid chromatography (RPLC) using methanol/water as mobile phase. The COP-1-packed column exhibited excellent separation performance toward various racemic compounds including alcohols, amines, ketones, esters, epoxy compounds, organic acids, and amino acids in NPLC and RPLC modes. The effects of analyte mass and column temperature on the separation efficiency of racemic compounds were investigated. In addition, the chiral resolution ability of the COP-1-packed column not only can be complementary in RPLC/NPLC modes but also exhibit a good chiral recognition complementarity with Chiralpak AD-H column and chiral porous organic cage (POC) NC1-R column. The relative standard deviations (RSD) (n = 5) of the retention time, resolution value, and peak area by repeated separation of 1-(4-chiorophenyl)ethanol are all below 3.0%. The COP-1 column shows high column efficiency (e.g., 17,320 plates m-1 for 1-(4-chlorophenyl)ethanol on COP-1 column in NPLC), high enantioselectivity, and good reproducibility toward various racemates. This work demonstrates that chiral POPs microspheres are promising chiral materials for HPLC enantioseparation.

Novel PDMS-b-PPO Membranes Modified with Graphene Oxide for Efficient Pervaporation Ethanol Dehydration

Purification and concentration of bioalcohols is gaining new status due to their use as a promising alternative liquid biofuel. In this work, novel high-performance asymmetric membranes based on a block copolymer (BCP) synthesized from polydimethylsiloxane (PDMS) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) were developed for enhanced pervaporation dehydration of ethanol. Improvement in dehydration performance was achieved by obtaining BCP membranes with a “non-perforated” porous structure and through surface and bulk modifications with graphene oxide (GO). Formation of the BCP was confirmed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies. The changes to morphology and physicochemical properties of the developed BCP and BCP/GO membranes were studied by scanning electron (SEM) and atomic force (AFM) microscopies, thermogravimetric analysis (TGA) and contact angle measurements. Transport properties of the developed membranes were evaluated by the pervaporation dehydration of ethanol over a wide concentration range (4.4–70 wt.% water) at 22 °C. The BCP (PDMS:PPO:2,4-diisocyanatotoluene = 41:58:1 wt.% composition) membrane modified with 0.7 wt.% GO demonstrated optimal transport characteristics: 80–90 g/(m2h) permeation flux with high selectivity (76.8–98.8 wt.% water in the permeate, separation factor of 72–34) and pervaporation separation index (PSI) of 5.5–2.9.

Highly Sensitive Ethanol Sensing Using NiO Hollow Spheres Synthesized via Hydrothermal Method

Excessive ethanol gas is a huge safety hazard, and people will experience extreme discomfort after inhalation, so efficient ethanol sensors are of great importance. This article reports on ethanol gas sensors that use NiO hollow spheres assembled from nanoparticles, nanoneedles, and nanosheets prepared by the hydrothermal method. All of the samples were characterized for performance evaluation. The sensors based on the NiO hollow spheres showed a good response to ethanol, and the hollow spheres assembled from nanosheets (NiO-S) obtained the best ethanol gas-sensing performance. NiO-S provided a larger response value (38.4) at 350 °C to 200 ppm ethanol, and it had good stability and reproducibility. The nanosheet structure and the fluffy surface of NiO-S obtained the largest specific surface area (55.20 m2/g), and this structure was beneficial for the sensor to adsorb more gas molecules in an ethanol atmosphere. In addition, the excellent sensing performance could ascribe to the larger Ni3+/Ni2+ of NiO-S, which achieved better electronic properties. Furthermore, in terms of commercial production, the template-free preparation of NiO-S eliminated one step, saving time and cost. Therefore, the sensors based on NiO-S will serve as candidates for ethanol sensing.

Construction of PdCo catalysts on Ni bowl-like micro/nano array films for efficient methanol and ethanol electrooxidation

Direct alcohol fuel cells (DAFCs) are renewable energy sources with the potential to replace fossil fuels. Investigating high-performance electrocatalysts that promote alcohol oxidation is critical. In this study, we demonstrate simple electrodeposition for the controlled synthesis of PdCo catalysts on Ni bowl-like micro/nano array films with the assistance of the monodisperse colloidal sphere template. The PdCo catalysts with the optimal properties was synthesized by optimizing the stirring rate of the electrolyte and the solution concentration. The Pd8Co1/Ni array film catalyst synthesized at a stirring speed of 200 Revolutions Per Minute (RPM) exhibited the highest electrochemical active surface area (ECSA, 95.65 cm2/mg) and specific and mass activities in methanol (173.2 mA/cm2 and 2032.9 mA/mgPd, respectively) and ethanol (240.1 mA/cm2 and 2846.1 mA/mgPd, respectively) oxidation in alkaline media. This was a considerable improvement compared to the electrocatalytic activities of single-phase Pd and a commercial Pd/C catalyst, and the superior performance of the Pd8Co1 micro/nano array film could be attributed to the bowl-like structure with a high ECSA and the synergistic effect of Pd and Co. Therefore, this study yields necessary insights into the development of high-performance electrocatalysts with potential applications in DAFCs.