Electrocatalytic Oxidation Of Ethanol Research Articles

2D petal-like PdAg nanosheets promote efficient electrocatalytic oxidation of ethanol and methanol.

The development of efficient alcohol electrooxidation catalysts is of vital importance for the commercialization of direct liquid fuel cells. As emerging advanced catalysts, two-dimensional (2D) noble metal nanomaterials have attracted much research attention due to their intrinsic structural advantages. Herein, we report the synthesis of petal-like PdAg nanosheets (NSs) with an ultrathin 2D structure and jagged edges via a facile wet-chemical approach, combining doping engineering and morphology tuning. Notably, the highly active sites and Pd-Ag composition endowed PdAg NSs with improved toxicity tolerance and substantially improved the durability toward the ethanol/methanol oxidation reaction (EOR/MOR). Moreover, the electronic effect and synergistic effect significantly enhanced the EOR and MOR activities in comparison with Pd NSs and commercial Pd/C. This work provides efficient catalysts for fuel electrooxidations and deep insight into the rational design and fabrication of novel 2D nanoarchitecture.

Optimized Electrodeposition of Ni2O3 on Carbon Paper for Enhanced Electrocatalytic Oxidation of Ethanol.

The urgent need for sustainable and efficient energy conversion technologies has propelled research into novel electrocatalysts for fuel cell applications. This study investigates a carbon paper (CP)-supported Ni2O3 catalyst for the electrocatalytic oxidation of ethanol. We utilized electrodeposition to uniformly deposit/dop Ni2O3 onto the CP, creating an effective electrocatalyst. Our approach allows the tailoring of the doping degree by adjusting the electrodeposition potential. The optimal doping degree, achieved at a medium deposition potential, results in an electrode with high intrinsic activity and a substantial electrochemically active surface area (ECSA), thereby enhancing its electrocatalytic activity. This catalyst efficiently facilitates the oxidation of ethanol to formic acid while maintaining good stability. The enhanced performance is attributed to the effective interface and interaction between Ni2O3 and CP. This work not only provides insights into the design of efficient Ni-based catalysts for ethanol oxidation but also paves the way for developing advanced materials for renewable energy conversion.

Toward Developing Superior Cu-Based Metal-Organic Framework-Derived Materials for Electrocatalytic Oxidation of Ethanol.

This project addresses the urgent need for efficient and cost-effective development of electrocatalysts for the ethanol oxidation reaction (EOR). This reaction offers promising renewable energy solutions but faces challenges due to the slow EOR kinetics, typically requiring costly noble metal catalysts. To overcome these limitations, this study focuses on developing CuZn-based EOR catalysts derived from metal-organic frameworks (MOFs), focusing on understanding the structure-performance relationship between pristine MOF-based electrocatalysts and their pyrolyzed counterparts. Herein, bimetallic MOF materials with varying Cu/Zn ratios were synthesized, followed by pyrolysis to produce carbonized counterparts while preserving the fundamental structure but with altered physicochemical properties. Comparative EOR studies revealed the superior performance of pyrolyzed MOFs, demonstrating that optimized Zn-loading is crucial over Cu-based framework for catalyst performance and durability. Overall, this work highlights the potential of MOF-derived Cu-based catalysts for renewable energy applications and provides insights into optimizing their performance through controlled synthesis and post-treatment strategies.

Bioelectrocatalytic Activity of One-Dimensional Porous Pt Nanoribbons for Efficient Inhibition of Tumor Growth and Metastasis.

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.

Local coordination and electronic interactions of Pd/MXene via dual‐atom codoping with superior durability for efficient electrocatalytic ethanol oxidation

AbstractCatalyst design relies heavily on electronic metal‐support interactions, but the metal‐support interface with an uncontrollable electronic or coordination environment makes it challenging. Herein, we outline a promising approach for the rational design of catalysts involving heteroatoms as anchors for Pd nanoparticles for ethanol oxidation reaction (EOR) catalysis. The doped B and N atoms from dimethylamine borane (DB) occupy the position of the Ti3C2 lattice to anchor the supported Pd nanoparticles. The electrons transfer from the support to B atoms, and then to the metal Pd to form a stable electronic center. A strong electronic interaction can be produced and the d‐band center can be shifted down, driving Pd into the dominant metallic state and making Pd nanoparticles deposit uniformly on the support. As‐obtained Pd/DB–Ti3C2 exhibits superior durability to its counterpart (∼14.6% retention) with 91.1% retention after 2000 cycles, placing it among the top single metal anodic catalysts. Further, in situ Raman and density functional theory computations confirm that Pd/DB–Ti3C2 is capable of dehydrogenating ethanol at low reaction energies.

Rational modulation of electronic structure in PtAuCuNi alloys boosts efficient electrocatalytic ethanol oxidation assisted with energy-saving hydrogen evolution

Compared to conventional electrocatalytic water splitting, electrocatalytic ethanol oxidation reaction (EOR) along with hydrogen production is considered a more energy-efficient strategy. Herein, we prepared a type of novel quaternary alloy catalyst (PtAuCuNi@NF) that exhibits excellent activity for EOR (0.215 V at 10 mA cm−2) and hydrogen evolution reaction (HER) (7 mV at 10 mA cm−2). Experimental results demonstrated that both Cu and Ni modulated the electronic environment around Pt and Au. The electron-rich active center facilitates the rapid adsorption and dissociation of reactants and intermediates for both EOR and HER. Impressively, in the ethanol-assisted overall water splitting (E-OWS), a current density of 10 mA cm−2 was achieved at 0.28 V. Moreover, an advanced acid-base self-powered system (A-Bsps) that can achieve a self-powered voltage of 0.59 V was assembled. Accordingly, the self-driven hydrogen production with zero external power supply was realized by integrating A-Bsps with the E-OWS equipment. The interesting results can provide a feasible strategy for designing and developing advanced nanoalloy-based materials for clean energy integration and use in various fields.

Wet‐Chemical Epitaxial Growth of Metastable‐Phase Intermetallic Electrocatalysts

AbstractMetastable‐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.

Strain effect induced Pd nanoparticles decorated Pd2+-doped Co3O4 nanosheets for efficient electrocatalytic ethanol oxidation and oxygen reduction reactions

Reactive metal-support interaction (RMSI) is an effective means of inducing surface strain and charge transfer in catalysts, which further enhances electrochemical activity and modulates reaction pathways. Nevertheless, the precise synthesis of nanomaterials with tunable strain and unique morphology remains a challenge. In this work, we have synthesized Pd nanoparticles decorated Pd2+- doped Co3O4 nanosheets (Pd7.4%/Co3O4) by a NaBH4 reduction method, which exhibit excellent performance for ethanol oxidation reaction (EOR) and oxygen reduction reaction (ORR). The introduction of the Pd into the Co3O4 by the means of elemental doping and nanoparticle decoration, and the resulting lattice strain and electron redistribution are responsible for the improved performance. Meanwhile, Pd7.4%/Co3O4 has a relatively low d-band center that reduces the adsorption energy of reaction intermediates to improve reaction selectivity and eliminate EOR toxic intermediates, ultimately promoting reaction kinetics. This work demonstrates a simple and effective strategy to manipulate lattice strain and electronic coupling and provides a novel and advanced way for the development of low-cost and high-quality direct ethanol fuel cells (DEFCs) catalysts.

Electrocatalytic Oxidation of Methanol and Ethanol with 3d-Metal Based Anodic Electrocatalysts in Alkaline Media Using Carbon Based Electrode Assembly.

Homogeneous electrocatalytic systems based on readily available, earth-abundant, inexpensive base metals Ni, Co, and Cr have been formulated for the electro-oxidation of alcohols (methanol and ethanol) that constitute a key half-cell component of direct alcohol fuel cells (DAFCs). Notably, excellent results were obtained for both methanol as well as ethanol electro-oxidation while operating with a half-cell assembly based on all-non-noble working and counter electrode systems consisting of glassy carbon and graphite rod, respectively. Using NaOH as the supporting electrolyte, Ni/Co/Cr metal salts and their bis(iminopyridine) complexes have been used as anodic electrocatalysts for the alcohol half-cell reactions, and among them, catalytic systems based on Co outperformed the corresponding systems based on Ni and Cr. The system comprising CoCl2.·6H2O [10 mM] + NaOH [6 M] at room temperature emerged as the best electrocatalyst for both methanol [5 M] electro-oxidation (ca. 522.5 ± 13.5 mA cm-2 at 1.4 V) and ethanol [5 M] electro-oxidation (ca. 209 ± 25 mA cm-2 at 1.34 V). It was observed that regardless of the starting alcohol, the end product is carbon dioxide, all of which gets trapped as sodium carbonate (up to 97% yield), thereby mitigating any possible hazards of greenhouse gas emission. Inferences obtained from FETEM, FESEM, and EDS analysis of both the electrolyte solution and residues deposited on the electrode surface provide evidence for the mostly homogeneous nature of the reaction mixture with the molecular catalyst being the major contributor toward the electrocatalytic activity apart from the minor role played by trace heterogeneous particles. The current cell assembly operating with non-noble working and counter electrodes utilizing a catalytic system based on an earth-abundant, base metal salt/complex that not only results in good half-cell current densities for high-energy power-source DAFCs but also generates high-value sodium carbonate offers an exciting avenue.

One-pot synthesis of PdAuAg nanocrystals for efficient electrocatalytic oxidation of ethanol: achieving morphology control by independently adjusting metal-atom concentrations

Versatile morphology control over PdAuAg nanocrystals is realized by introducing the three metallic precursor solutions at independently-controlled rates, which exhibit exceptional performance as EOR electrocatalysts.

High-entropy PtCuSnWNb nanoalloys as efficient and stable catalysts for ethanol oxidation electrocatalysis.

Ternary nanoalloys used as electrochemical ethanol oxidation catalysts for direct ethanol fuel cells are confronted with poor stability issues under harsh acidic operating conditions. To address this issue, a carbon-supported quinary PtCuSnWNb high-entropy nanoalloy (denoted as PtCuSnWNb/C) was synthesized by using a polyol reduction method. Due to the unique high-entropy mixing states and strong catalyst-support interactions, PtCuSnWNb/C shows robust structural and compositional stability.

Amorphous cobalt–nickel borides boost electrocatalytic ethanol oxidation coupled with energy-saving hydrogen production

We report an amorphous heterogeneous catalyst composed of boride and tungstate, which realizes the upgrading of ethanol oxidation coupled with energy saving hydrogen production.

A comparative study of α-Ni(OH)2 and Ni nanoparticle supported ZIF-8@reduced graphene oxide-derived nitrogen doped carbon for electrocatalytic ethanol oxidation.

Ethanol electrooxidation is an important reaction for fuel cells, however, the major obstacle to ethanol electrocatalysis is the splitting of the carbon-carbon bond to CO2 at lower overpotentials. Herein, a ZIF-8@graphene oxide-derived highly porous nitrogen-doped carbonaceous platform containing zinc oxide was attained for supporting a non-precious Ni-based catalyst. The support was doped with the disordered α-phase Ni(OH)2 NPs and Ni NPs that are converted to Ni(OH)2 through potential cycling in alkaline media. The Ni-based catalysts exhibit high electroactivity owing to the formation of the NiOOH species which has more unpaired d electrons that can bond with the adsorbed species. From CV curves, the EOR onset potential of the α-Ni(OH)2/ZNC@rGO electrode is strongly shifted to negative potential (Eonset = 0.34 V) with a high current density of 8.3 mA cm-2 relative to Ni/ZNC@rGO. The high catalytic activity is related to the large interlayer spacing of α-Ni(OH)2 which facilitates the ion-solvent intercalation. Besides, the porous structure of the NC and the high conductivity of rGO facilitate the kinetic transport of the reactants and electrons. Finally, the catalyst displays a high stability of 92% after 900 cycles relative to the Ni/ZNC@rGO and commercial Pt/C catalysts. Hence, the fabricated α-Ni(OH)2/ZNC@rGO catalyst could be regarded as a potential catalyst for direct EOR in fuel cells.

Fabrication of Self-Standing Porous Foam-like PdM (M = Ni, Fe, Co) Nanocrystals for Boosted Ethanol Oxidation Electrocatalysis

Rational designing of self-standing porous foam-like PdM (M = Ni, Fe and Co) nanocrystals was achieved by a fast aqueous-solution method via the co-reduction of metal precursors using sodium borohydride. This was based on the crystallites’ coalescence growth mechanism, including quick nucleation of Pd that served as starting seeds for the nucleation of M, which attached directly along the specific crystallographic and lowered its high surface energy by diffusion of PdM atoms across the interface via Brownian motion to afford self-standing porous foam-like PdM nanocrystals. Amongst the as-prepared PdM nanocrystals, PdNi nanocrystals showed a superior alkaline ethanol oxidation reaction (EOR) activity and stability compared to PdFe, PdCo, Pd nanospheres (Pd-NSs) and commercial Pd/C (10 wt.%) catalysts. The EOR mass activity of PdNi was 1.32, 1.51, 2.01 and 24.05 times than those of PdFe, PdCo, Pd-NSs and Pd/C, respectively based on equal Pd mass. This was attributed to the lower synergistic effect in PdNi, which enhanced H2O activation/dissociation to give OH- species needed for rapid EOR kinetics, meanwhile, the porous foam-like morphology improved electron mobility and increased accessible active sites. This study revealed that low synergism in porous PdM nanocrystals is beneficial for enhancing the EOR activity and durability, which may allow the design of other binary Pd-based alloys for various electrocatalytic reactions.

Ag/Ag2O electrode for electrocatalytic oxidation of ethanol

A film of silver oxide is grown on an Ag electrode in KOH solutions, by repetitive cyclic voltammograms at a high scan rate of 2500 mV/s. The formed film is used for the electro-oxidation of ethanol in a dilute potassium hydroxide using the cyclic voltammetry technique. Some effective experimental parameters such as the ethanol concentration, KOH concentration, scanning rate, and temperature on the electrocatalytic oxidation of ethanol have been investigated and discussed. The data confirmed that the formed silver oxide electrode behaves as a good catalyst for the electrooxidation of ethanol. The mechanism of oxidation is likely to be dissociative chemisorption involving one electron transfer. The apparent activation energy, E*, for the electrooxidation, was found to be 68.23 kJ/mole, which is considered too high for a pure diffusion process and moderate for a pure adsorption process. Then the charge transfer is probably controlled by a mixed adsorption-diffusion process

Self-Interface in Rh Nanosheets-Supported Tetrahedral Rh Nanocrystals for Promoting Electrocatalytic Oxidation of Ethanol.

Direct ethanol fuel cells hold great promise as a power source. However, their commercialization is limited by anode catalysts with insufficient selectivity toward a complete oxidation of ethanol for a high energy density, as well as sluggish catalytic kinetics and low stability. To optimize the catalytic performance, rationally tuning surface structure or interface structure is highly desired. Herein, a facile route is reported to the synthesis of Rh nanosheets-supported tetrahedral Rh nanocrystals (Rh THs/NSs), which possess self-supporting homogeneous interface between Rh tetrahedrons and Rh nanosheets. Due to full leverage of the structural advantages within the given structure and construction of interfaces, the Rh THs/NSs can serve as highly active electro-catalysts with excellent mass activity and selectivity toward ethanol electro-oxidation. The in situ Fourier transform infrared reflection spectroscopy showed the Rh THs/NSs exhibit the highest C1 pathway selectivity of 23.2%, far exceeding that of Rh nanotetrahedra and Rh nanosheets. Density function theory calculations further demonstrated that self-interface between Rh nanosheets and tetrahedra is beneficial for C-C bond cleavage of ethanol. Meanwhile, the self-supporting of 2D nanosheets greatly enhance the stability of tetrahedra, which improves the catalytic stability.

Facile synthesis of Ni/sepiolite and its excellent performance toward electrocatalytic ethanol oxidation

Facile synthesis of Ni/sepiolite and its excellent performance toward electrocatalytic ethanol oxidation

Assembly of Alloyed PdM (Ag, Cu, and Sn) Nanosheets and Their Electrocatalytic Oxidation of Ethanol and Methanol.

Direct alcohol fuel cells are popular due to their high energy density, abundant sources, and ease of transportation and storage. Palladium-based nanosheet self-assembled materials have emerged as an effective catalyst for alcohol oxidation reactions. In this work, nanosheets were synthesized with the same feeding ratio assembly of alloyed PdM (M = Ag, Cu, and Sn). The introduction of the second element was able to enhance the catalytic response of the catalysts to alcohol electrooxidation. Among them, the PdCu alloy exhibited the best performance in terms of catalytic activity, toxicity resistance, and stability to ethanol oxidation reaction (EOR) and methanol oxidation reaction (MOR). The catalytic current densities for EOR can reach 2226, 2518, and 1598 mA mg-1 for PdAg, PdCu, and PdSn nanosheet assemblies, respectively. These are mainly attributed to better electronic effects, altered atomic distances within the cell for the d-band centers of Pd, and a larger electrochemical active surface area (ECSA). The optimized d-band center is beneficial to promote the catalytic performance of EOR and MOR. Experimental data also demonstrated that higher electrocatalytic temperature, higher pH, and higher alcohol concentration can accelerate the rate of alcohol electrooxidation. These results have the potential to be extended to Pd-M (M = other metals) nanosheets and help for a wider range of catalytic applications.

Bismuth Incorporation in Palladium Hydride for the Electrocatalytic Ethanol Oxidation with Enhanced CO Tolerance.

Introducing nonmetal and oxophilic metal into palladium (Pd)-based catalysts is beneficial for boosting electrocatalysis, especially regarding the improvement of mass activity (MA) and CO tolerance. Herein, the stable bismuth-doped palladium hydride (Bi/PdH) networks have been successfully fabricated through a simple one-step method. The intercalation of interstitial H atoms expands the lattice of Pd, and the doping of oxophilic metal Bi restrains the adsorption of poisonous intermediates on the surface of Pd, thereby improving the activity and durability of the as-prepared catalysts in the ethanol oxidation reaction (EOR). The obtained Bi/PdH networks manifest a remarkable MA of 8.51 A·mgPd-1, which is 11.18 times higher than that of commercial Pd/C (0.76 A·mgPd-1). The CO-stripping analysis results indicate that Bi doping can significantly prohibit CO adsorption on the surface of the Bi/PdH networks. The density functional theory (DFT) calculations also reveal that Bi doping enhances the OH* adsorption on the catalyst surface and mitigates the interaction between Pd and CO* intermediates, providing deeper insights into the origin of the enhanced EOR activity and CO tolerance. This work describes an impactful path for producing high-performance and durable PdH-based nanocatalysts.

Enhanced hydrogen production coupled with ethanol electrocatalytic oxidation by flow-through self-supporting electrode

Electrocatalytic oxidation of ethanol to value-added production is an ideal replacement of the conventional anodic oxygen evolution reaction (OER) for efficient hydrogen (H2) production due to the lower electric potential energy and higher safety. However, the sluggish mass transfer rate of reactants commonly is the crucial limitation of electrocatalytic oxidation efficiency. Here, Ni(OH)2 nanosheet is immobilized on nickel foam (NF) to fabricate a flow-through self-supporting electrode (Ni(OH)2/NF) served as anode for ethanol electrocatalytic oxidation, in coupling with high-purity H2 production at the cathode. The potential for electrocatalytic oxidation of ethanol and H2 evolution was significantly reduced by 200 mV compared to pure water splitting at 25 mA cm−2. The boundary layer thickness on the anodic electrode surface could be decreased from 86.66 μm to 66.21 μm with the flow rate increased from 0 to 0.82 cm min−1. Compared to the batch mode, The conversion rate of ethanol can be increased from 59 % to 100 % and the selectivity of acetic acid can be increased from 88 % to 100 % under the flow-through mode. The Faraday efficiency of the anode achieved an increase from 76 % to over 99 % and the H2 production of the cathode increased by 31 % under the flow-through mode.