Ethylene Glycol Electrooxidation Research Articles

High-efficient electrooxidation of ethylene glycol and ethanol on PdSn alloy loaded by versatile poly(3,4-ethylenedioxythiophene)

Developing a novel catalyst with lower noble-metal loading and higher catalytic efficiency is significant for promoting the widespread application of direct alcohol fuel cells (DAFCs). In this work, poly(3,4-ethylenedioxythiophene) (PEDOT) supported the PdSn alloy (PdSn/PEDOT) were simply synthesized and their electrocatalytic performance toward the oxidation of ethylene glycol and ethanol (EGOR and EOR) were investigated in alkaline media, respectively. In comparison with other control catalysts, the optimized Pd4Sn6/PEDOT catalyst exhibits the highest mass activity (7125/4166 mA mgPd−1) and specific activity (26/15 mA cm−2) towards EGOR/EOR. The mass activity of Pd4Sn6/PEDOT for EGOR and EOR are 11.9 and 10.9 times higher than commercial Pd/C, respectively. Moreover, chronoamperometry (CA) and successive cyclic voltammetry (CV) tests show that the CO resistance ability and durability of the Pd4Sn6/PEDOT catalyst were superior to Pd4Sn6, Pd/PEDOT and commercial Pd/C catalysts, which can be attributed to the d-band center of Pd can be effectively downshifted and the interface strain effect between electrons caused by the conjugated structure between PEDOT groups. This work provides an effective strategy for the development of highly efficient anode catalysts of DAFCs.

Enzymatic Mesoporous Metal Nanocavities for Concurrent Electrocatalysis of Nitrate to Ammonia Coupled with Polyethylene Terephthalate Upcycling.

Electrochemical upcycling of waste pollutants into high value-added fuels and/or chemicals is recognized as a green and sustainable solution that can address the resource utilization on earth. Despite great efforts, their progress has seriously been hindered by the lack of high-performance electrocatalysts. In this work, bimetallic PdCu mesoporous nanocavities (MCs) are reported as a new bifunctional enzymatic electrocatalyst that realizes concurrent electrocatalytic upcycling of nitrate wastewater and polyethylene terephthalate (PET) plastic waste. Abundant metal mesopores and open nanocavities of PdCu MCs provide the enzymatic confinement of key intermediates for the deeper electroreduction of nitrate and accelerate the transport of reactants/products within/out of electrocatalyst, thus affording high ammonia Faradic efficiency (FENH3) of 96.6% and yield rate of 5.6mgh-1mg-1 at the cathode. Meanwhile, PdCu MC nanozymes trigger the selective electrooxidation of PET-derived ethylene glycol (EG) into glycolic acid (GA) and formic acid with high FEs of >90% by a facile regulation of potentials at the anode. Moreover, concurrent electrosynthesis of value-added NH3 and GA is disclosed in the two-electrode coupling system, further confirming the high efficiency of bifunctional PdCu MC nanozymes in producing value-added fuels and chemicals from waste pollutants in a sustainable manner.

Corrosion Engineering of Part-Per-Million Single Atom Pt1/Ni(OH)2 Electrocatalyst for PET Upcycling at Ampere-Level Current Density.

The plastic waste issue has posed a series of formidable challenges for the ecological environment and human health. While conventional recycling strategies often lead to plastic down-cycling, the electrochemical strategy of recovering valuable monomers enables an ideal, circular plastic economy. Here a corrosion synthesized single atom Pt1/Ni(OH)2 electrocatalyst with part-per-million noble Pt loading for highly efficient and selective upcycling of polyethylene terephthalate (PET) into valuable chemicals (potassium diformate and terephthalic acid) and green hydrogen is reported. Electro-oxidation of PET hydrolysate, ethylene glycol (EG), to formate is processed with high Faraday efficiency (FE) and selectivity (>90%) at the current density close to 1000mAcm-2 (1.444V vs RHE). The in situ spectroscopy and density functional theory calculations provide insights into the mechanism and the understanding of the high efficiency. Remarkably, the electro-oxidation of EG at the ampere-level current density is also successfully illustrated by using a membrane-electrode assembly with high FEs to formate integrated with hydrogen production for 500h of continuous operation. This process allows valuable chemical production at high space-time yield and is highly profitable (588-700$ton-1 PET), showing an industrial perspective on single-atom catalysis of electrochemical plastic upcycling.

One-pot Synthesis of PdCuAg and CeO2 Nanowires Hybrid with Abundant Heterojunction Interface for Ethylene Glycol Electrooxidation.

Introducing CeO2 into Pd-based nanocatalysts for electrocatalytic reactions is a good way to solve the intermediate toxicity problem and improve the catalytic performance. Here we reported a simple strategy to synthesize the PdCuAg and CeO2 nanowires hybrid via a one-pot synthesis process under strong nanoconfined effect of specific surfactant as templates. Owing to the structural (ultrathin nanowires, abundant heterojunction/interfaces between metal and metal oxide) and compositional (Pd, Cu, Ag, CeO2) advantages, the hybrid showed significantly enhanced catalytic activity (6.06 A mgPd -1) and stability, accelerated reaction rate, and reduced activation energy toward electrocatalytic ethylene glycol oxidation reaction.

Energy‐Saving Hydrogen Production by Seawater Splitting Coupled with PET Plastic Upcycling

AbstractDirect seawater electrolysis presents a promising route for grid‐scale green hydrogen (H2) production without reliance on scarce freshwater. However, it is severely hampered by high energy consumption (> 4.3–5.73 kWh m−3 H2) and harmful chlorine corrosion. Herein, an energy‐saving and chlorine‐free H2 production system by coupling seawater splitting and upcycling of polyethylene terephthalate (PET) waste into value‐added glycolic acid (GA) over a Pd─CuCo2O4 catalyst is reported. An ultra‐low potential of 1.15 V versus RHE is required to achieve an industry‐level current density of 600 mA cm−2, which reduces electricity cost to 2.45 kWh m−3 H2. Notably, this system maintains 1.6 A for longer than 100 h, demonstrating excellent stability. Experimental and theoretical results unveil that 1) the specific adsorption of PET‐derived ethylene glycol (EG) on Pd enhances the catalytic performance, and the downshifted d‐band center of Pd accelerates the desorption of GA to prevent over‐oxidation; 2) the strong adsorption of OH− on CuCo2O4 synergistically promotes EG electrooxidation (EGOR) and forms a negative charge layer that effectively repels Cl− by electrostatic repulsion, thus preventing chlorine corrosion. This work may provide new opportunities for H2 production and value‐added GA from vast marine resources and PET waste.

Effective PdPtMoCrCoNi alloy nanosheets boost electrocatalytic activity and stability for ethylene glycol oxidation

In the realm of traditional electrocatalytic processes, the benefits of composition and two-dimensional ultrathin morphology have not often been explored in the context of multicomponent palladium-based nanosheets. In this work, we utilize a one-step solvothermal method to create nanosheets of a multicomponent alloy (PdPtMoCrCoNi NSs). The synthesis involves no surfactants, allowing for the exposure of more active sites or surface atoms. The resulting PdPtMoCrCoNi NSs exhibits outstanding performance in the electrooxidation of ethylene glycol under alkaline conditions, demonstrating high mass activity (10.12 A mgPd+Pt−1), good stability, and enhanced anti-poisoning ability. The incorporation of more low-cost alloyed elements not only reduces the overall cost of electrocatalysts but also effectively tailors the electronic state to enhance the corresponding electrocatalytic performance.

Pd/fMC−NiO Synergistic, Promotional Effect and Cooperation Induced Electrocatalysis towards Ethylene Glycol Electrooxidation: Experimental Approach and DFT Calculations

AbstractDirect alcohol fuel cells (DAFCs) face several challenges such as carbon support corrosion, poor kinetics, and long‐term stability, requiring improved electrocatalyst support development. We synthesized 5 %Pd/fMC−NiO using a microwave‐assisted sodium borohydride‐enhanced polyol method. X‐ray photoelectron spectroscopy, transmission electron microscope, and X‐ray diffractometry probed the material's surface composition, morphology, and structure. ICP‐OES is employed to quantify palladium loading. Fourier Transform Infrared Spectroscopy mapped the functional groups. Cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy, and chronoamperometry show that the 5 %Pd/fMC−NiO has the lowest activation energy, and with that, the best electroactivity, which is ~16 times higher compared to commercial Pd/C; additionally, the catalyst shows anti‐poisoning properties, and long‐term durability. This is merited to the cooperation and promotional effect of Pd/fMC−NiO. The electrocatalysts’ electroactivity improved via enhanced electron movement instigated by NiO. This study introduced the parallelism effect concept borrowed from the graphite structure for controlled electron channeling the 5 % Pd/fMC−NiO electrocatalyst. The theoretical calculations corroborated the experimental findings that our approach favors anchoring and dispersing Pd NPs uniformly, demonstrating NiO′s cooperative and promotional effects. Thus, opening new opportunities for the development of electrocatalysts for high‐performance DAFCs.

Bi2Te3 nanosheets promoted Pd for ethylene glycol electrooxidation both in the dark and under visible light irradiation.

Ethylene glycol electrooxidation catalyzed by Pd nanoparticles was found to be largely improved by Bi2Te3 nanosheets both in the dark and under visible light irradiation.

Pd11Ni11Pt2 nanoparticles with three-phase surface enrichment for facilitating electrooxidation of ethanol and ethylene glycol

Rational surface/interface engineering of Pd-based materials plays an extremely important role in boosting the electrooxidation of liquid fuels.

Synthesis and characterization of enhanced carbon nanotube-supported PtRuBi alloy catalyst for ethylene glycol electrooxidation

At present, carbon nanotube (CNT)-supported Pt-based catalysts are prepared by the sodium borohydride (SBH) method for catalytic ethylene glycol (EG) electrooxidation. The structural and morphology surface analyses of these catalysts are characterized by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray (SEM-EDX) and mapping analysis, transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). In addition, the catalytic activity and electrochemical surface area (ECSA) of the catalysts are examined by cyclic voltammetry (CV). The 10 % PtRuBi(80-10-10)/CNT catalyst exhibited the best catalytic activity with a specific activity of 6.10 mA/cm2 and an ECSA value of 488.42 m2/g. Furthermore, it is observed that it exhibited the best stability and resistance by chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) analyses. It can be a promising anode catalyst for direct EG fuel cells.

Impact of Pt-Ni Nanoparticle Architecture on Electrocatalytic Oxidation Reaction in Fuel Cells

This paper investigates how the aggregation of bimetallic nanoparticles (NPs) influences the electronic condition of the surface adsorption site and, hence, the performance of materials during the electrooxidation of fuels in an alkaline medium. First, we synthesized Pt-Ni NPs in three configurations: ordered intermetallic, ordinary alloy, and core-shell. The NPs contained Pt and Ni close to a 1:1 Pt/Ni atomic ratio. They had similar particle sizes, which allowed us to evaluate their performance without the influence of these physical parameters. Depending on the structural arrangement of the Pt and Ni atoms in the NP, the electronic condition of the surface adsorption site (Pt) changed significantly. Consequently, the performance of the materials varied whenever they were used as anode material for the electrooxidation of hydrogen, methanol, ethanol, ethylene glycol, and glycerol in an alkaline solution. The electronic condition of the surface site strongly affected the adsorption characteristics of the reactants, intermediates, and products, consequently impacting the material's performance during the electrochemical processes. The approach adopted here could contribute to a better understanding of electrocatalytic processes and the design of selective electrocatalysts.

Oxygen vacancy-enriched NiCo2O4 spinels/N-doped carbon nanotubes-graphene composites for the ethylene glycol electro-oxidation

The efficient electro-oxidation of alcohol fuels on non-platinum group metals (non-PGMs) is a crucial challenge in advanced fuel cell technology. This study presents a novel approach, focusing on systematically designing highly efficient composites through strategic interface engineering. The method harnesses the intrinsic potential of oxygen vacancies (Ov) in the NiCo2O4 spinel, while synergistically incorporating nitrogen heteroatoms into multi-walled carbon nanotubes mixed with graphene (N-CNTG). Ethylene glycol (EG) was employed as defect promoter at 0, 33, 66 and 100 % v/v EG. Micrographs showed that nanobars were the predominant morphology at 0 % v/v EG, and this shape shifted to nanometric hemispheres with the shift to EG. X-ray photoelectron spectroscopy (XPS) showed that the Ov increased from 23 % to 36 % shifting from 0 to 100 % v/v EG. Comparative electrocatalytic studies showed the remarkable performance of the engineered composites compared to Vulcan carbon (C), a standard support. The best onset potential (1.08 V) was found on NiCo2O4 EG33/N-CNTG. The onset potential was 330 mV higher to that of a gold nanomaterial, but the peak potential difference was only 140 mV. This was associated with the improvement of the electronic structure as revealed by chemical calculations, changing adsorption energies, apparent activation energies and resistances to charge transfer. These findings highlight the potential of interface engineering in achieving non-PGMs electrocatalysts.

Concurrent electrocatalytic hydrogen evolution and polyethylene terephthalate plastics reforming by self-supported amorphous cobalt iron phosphide electrode

The electrocatalytic hydrogen evolution reaction (HER) coupled with oxidative transformation of plastics into commodity chemical is a promising tactic to relieve the energy shortage and white pollution problems via sustainable and profitable manner, which necessitates highly active bifunctional catalytic electrode and meticulous construction of electrolysis system. Herein, a self-supported amorphous cobalt iron phosphide onto nickel foam (NF) substrate, labeled as CoFe-P/NF, was prepared by electrodeposition, which served as bifunctional catalytic electrode for alkali hydrogen evolution reaction (HER) and selective electrooxidation of polyethylene terephthalate (PET) plastic hydrolysate toward formate. Benefiting from the abundant catalytic sites within amorphous structure, the interelement synergy and sufficient exposure of catalyst to electrolyte, the self-supported CoFe-P/NF electrode displayed low overpotential (η100 of 168 mV at current density of J = 100 mA cm−2), decent stability for HER and fine tolerance to PET monomers. The CoFe-P/NF electrode could also catalyze selective electrooxidation of ethylene glycol (EG) component in PET hydrolysate to formate with high productivity (0.1 mmol cm-2h−1) and faradaic efficiency (FE, 90 %) at 1.5 V. The PET hydrolysate electrolysis system based on CoFe-P/NF enabled coproduction of H2 and value added formate at lower voltage (1.52 V at J = 20 mA cm−2) and energy consumption (84 % at J = 200 mA cm−2) relative to water electrolysis. This work showcases the coproduction of H2 fuel and formate by electrolysis of PET hydrolysate via rational design of bifunctional catalytic electrode. We believe such type of versatile catalytic electrodes can find application scenarios in electrosynthesis of more commodity chemicals and energy devices beyond the case herein.

Energy-saving and product-oriented hydrogen peroxide electrosynthesis enabled by electrochemistry pairing and product engineering

Hydrogen peroxide (H2O2) electrosynthesis through oxygen reduction reaction (ORR) is drawing worldwide attention, whereas suffering seriously from the sluggish oxygen evolution reaction (OER) and the difficult extraction of thermodynamically unstable H2O2. Herein, we present an electrosynthesis protocol involving coupling ORR-to-H2O2 with waste polyethylene terephthalate (PET) upcycling and the first H2O2 conversion strategy. Ni-Mn bimetal- and onion carbon-based catalysts are designed to catalyze ORR-to-H2O2 and ethylene glycol electrooxidation with the Faradaic efficiency of 97.5% (H2O2) and 93.0% (formate). This electrolysis system runs successfully at only 0.927 V to achieve an industrial-scale current density of 400 mA cm−2, surpassing all reported H2O2 electrosynthesis systems. H2O2 product is upgraded through two downstream routes of converting H2O2 into sodium perborate and dibenzoyl peroxide. Techno-economic evolution highlights the high gross profit of the ORR || PET upcycling protocol over HER || PET upcycling and ORR || OER. This work provides an energy-saving methodology for the electrosynthesis of H2O2 and other chemicals.

Ultra-efficient electrooxidation of ethylene glycol enable by Pd-loaded Fe-doped Nb2O5 with abundant oxygen vacancies

Niobium pentoxide (Nb2O5) has emerged as a highly promising electrocatalyst for ethylene glycol oxidation reaction (EGOR) due to its eco-friendly nature and its ability to maintain structural stability in alkaline environments. However, its inherent electronic structure has posed a significant barrier to further enhancing of EGOR activity. In this study, we successfully synthesized Pd-based electrocatalysts by incorporating Fe-doped Nb2O5 with abundant oxygen vacancies (Pd/FNO-2.5), which effectively promoted ethylene glycol oxidation. The results showed that the introduction of Fe doping not only altered the electronic structure of Nb2O5, leading to the generation of oxygen vacancies, but also decreased the d-band center of Pd, thereby reducing thermodynamic energy barrier of the rate-determining step by approximately 0.58 eV. Impressively, the Pd/FNO-2.5 catalyst demonstrated remarkable electrocatalytic performance exhibiting a relatively low initial potential (−0.11 V) and high mass activity (0.380 A mg−1Pd). Furthermore, even after undergoing 100 consecutive recycling experiments, the Pd/FNO-2.5 catalyst still retained 81.10 % of its current density. This study demonstrates that doping-induced oxygen vacancy engineering is a promising approach for developing efficient EGOR electrocatalysts for direct ethylene glycol fuel cells, which is associating with the efficient and sustainable development of fuel cell and the carbon neutrality efforts.

Green synthesis of gallic acid–capped gold nanoparticles as novel electro-catalyst for electro-oxidation of ethylene glycol in alkaline media

This study reports the synthesis of gallic acid–capped gold nanoparticles (GA-AuNPs) through a simple, inexpensive, and environmentally friendly chemical method and their applications in fuel cells. In the proposed method, gallic acid acts as the reducing agent and stabilizer. The studies showed that the size and distribution of AuNPs could be controlled by controlling the molar ratio of gallic acid to gold ions. The prepared GA-AuNPs were used as an electro-catalyst to oxidize ethylene glycol (EG) molecules on the glassy carbon electrode (GCE) surface in alkaline media. The results showed that the modified electrode using GA-AuNPs with a 1:1 M ratio has a higher electrochemical active surface area (ECSA); therefore, it has improved electro-catalytic activity, increased stability, and durability for EG oxidation compared to other ratios of GA/Au and even to the bare Au electrode.

Electron Regulation of Heterostructured Pt/Rh Metallene Boosts Ethylene Glycol Electrooxidation and Hydrogen Evolution.

The research on high-efficiency two-dimensional (2D) catalytic materials for the small-molecule oxidation-assisted hydrogen evolution reaction (HER) is prospective for efficient hydrogen production. Herein, we report heterostructured Pt/Rh metallene with Pt nanoparticles (NPs) uniformly anchored on Rh metallene for the HER and ethylene glycol oxidation reaction (EGOR). The ultrathin sheet structure of the Pt/Rh metallene offers high surface areas and sufficient active sites. More importantly, the Pt/Rh heterostructure can optimize catalytic active centers and adjust electronic structure. Thus, Pt/Rh metallene exhibits superior electrocatalytic HER activity with a low overpotential of 28 mV in 1 M KOH at 10 mA cm-2 and EGOR activity with a specific activity of 8.39 mA cm-2 in 1 M KOH with 3 M EG, along with outstanding CO tolerance. In a two-electrode system, Pt/Rh metallene requires a low potential of 0.51 V for stable and efficient hydrogen production at 10 mA cm-2 in 1 M KOH + 3 M EG, with the simultaneous production of high-value-added products. The job proposes an attractive strategy for the synthesis of 0D/2D metallene toward simultaneous energy-saving hydrogen production and chemical update.

Nickel–cobalt oxides decorated Chitosan electrocatalyst for ethylene glycol oxidation

A composite of NiCo2O4 modified electrocatalyst is prepared to enhance the ethylene glycol electrooxidation. Chitosan matrix is used to improve the activity and adsorption ability of the surface to enhance ethylene glycol conversion. A Comparative study is investigated between pristine NiCo2O4 and Chitosan-modified spinel oxide to evaluate the synergistic effect between spinel oxide and chitosan. The composite is studied in an alkaline solution using electrochemistry techniques. The electrochemical activity towards ethylene glycol electrooxidation is studied as a function of anodic oxidation current density. Thus, the oxidation current values for NiCo2O4 and NiCo2O4@Chitosan in 1.0 M EG and 1.0 M KOH are 36 and 42 mA cm−2, respectively. The long-term stability of the electrode is measured by constant potential chronoamperometry. Kinetic parameters like diffusion coefficient, Tafel slope, surface coverage, and transfer coefficient are calculated. The density-functional theory estimates the adsorption of small molecules like ethylene glycol, urea, and carbon monoxide. The adsorption energy is studied on the top site of Ni and Co atoms of NiCo2O4. Forcite model is used to study the interaction between spinel oxide and chitosan. The energy calculation assumes that chitosan is adsorbed on the spinel oxide surface and enhances chitosan's ability for the adsorption of small molecules.

Room temperature syntheses of surfactant-free colloidal gold nanoparticles: The benefits of mono-alcohols over polyols as reducing agents for electrocatalysis

Developing sustainable strategies for energy conversion and chemical production remains a general challenge that can be addressed by the development of sustainable syntheses of nanocatalysts. Here, we explore colloidal syntheses of gold nanoparticles obtained at room temperature by a simple route that requires only an alcohol as reducing agent, water, a base and a gold precursor, without the need for extra reducing agents or stabilizers. To date, polyols-based syntheses were preferred but they suffer from multiple drawbacks related to the high viscosity and high boiling point of the solvents. We recently reported on the opportunities to use methanol and ethanol as alternative reducing agents. We illustrate further the benefits of using methanol and ethanol as reducing agents to prepare ca. 10–20 nm gold nanoparticles. We characterize the nanoparticles by UV–vis absorption, transmission electron microscopy and X-ray diffraction. The nanoparticles prepared in alkaline mono-alcohols lead to nanocatalysts up to three times more active for the ethanol and ethylene glycol electro-oxidation than nanoparticles prepared using polyols.

Correlating composition and electronic effects of self-assembled PtMo electrocatalysts for ethylene glycol oxidation: An experimental and theoretical approach

In recent years, there has been an increasing interest in using small organic molecules to convert chemical fuels into electrical energy. In this context, ethylene glycol (EG) is a potential feedstock due to its high energy density, which makes this molecule suitable for direct alcohol fuel cells. Thus, combining Pt atoms with other oxophilic elements, such as Mo, is a promising strategy based on the unrivaled importance of developing efficient electrocatalysts for this application. Herein, we report the engineering of PtMo nanoparticles (NPs) as the active phase for EG electrooxidation. Interestingly, a self-assembly process occurred during their manufacturing, and a simple NPs synthesis process (a modified one-pot polyol method) afforded nanostructures with virtually all Mo atoms inside the particles for different PtMo ratios. By preparing three PtMo ratios, we obtained the following NPs sizes: 2.74 ± 2.34 nm (Pt90Mo10), 2.16 ± 1.92 nm (Pt80M20), and 2.47 ± 2.09 nm (2.47 ± 2.09 nm). After immobilizing the NPs onto Vulcan XC-72 carbon black, we got different onset potentials/current densities (at 25 °C): Pt90Mo10/C (0.33 V/189.0 μA/cm2), Pt80Mo20/C (0.19 V/132.0 μA/cm2), and Pt70Mo30/C (0.24 V/95.0 μA/cm2) for the EG electrooxidation. However, essential understandings were raised regarding the studied systems: density-functional tight-binding-based (DFTB) calculations addressed the configuration of the metals in the obtained nanostructures; also, such an approach brought insights regarding the emergence of electronic properties of the different PtMo ratios and mechanistic insights corroborating analytical analyses performed by liquid chromatography. Hence, the best results could be attributed to tailored electronic effects based on a Mo-optimized quantity (Pt80Mo20/C electrocatalyst). Therefore, we believe we cooperated in better understanding PtMo-based systems, and how the metal ratio decisively can affect their performance, opening new opportunities for practical fuel cell applications.