Direct Ethylene Glycol Fuel Cells Research Articles

Flocculent-structured high-entropy-alloy anode electrocatalyst for direct ethylene glycol fuel cells

The Pt-based alloys catalysts with special morphology attract great attention. Herein, a flocculent-structured high-entropy-alloy (HEA) (named as F-PtBiCuCoMo/C) electrocatalyst is prepared by co-reduction, which can greatly improve the overall catalytic performance and reduce Pt-usage. In ethylene glycol oxidation reaction (EGOR), it has mass activity of 1.08 A mg−1Pt, which also has a good durability with high residual current density (0.27 A mg−1Pt after 3000 s). Notably, the power density reached 17.9 mW cm−2 in as-assembled direct ethylene glycol fuel cells (DEGFC), which exceeded commercial Pt/C references by 2.4 times. Thence, this F-PtBiCuCoMo/C electrocatalyst would be a good option for the advancement of DEGFC technology.

Developing high-effective Pt-based high-entropy-alloy electrocatalyst for direct ethylene glycol fuel cells

High entropy alloy (HEA) would be a good approach to improve electrocatalytic utilization of precious metals. Herein, a HEA catalyst of PtBiNiCoSn/C was used in the ethylene glycol oxidation reaction (EGOR) and finally applied to a direct ethylene glycol fuel cell (DEGFC). The results showed that the EGOR current density reached 1.406 A mg‐−1Pt, which exceeded those Pt/C references by 6.39 times. The remaining current density after 3000 s of chronoamperometry (CA) analysis is 0.208 A mg‐−1Pt, which is likewise significantly greater than Pt/C. Notably, the power density reached 8.49 mW cm−2 when combined into the DEGFC anode. This work provides a good HEA catalyst in DEGFC, would promote the widespread use of HEA materials in other electrocatalysis.

Mesoporous Mo-doped PtBi intermetallic metallene superstructures to enable the complete electrooxidation of ethylene glycol.

Metallenes, intermetallic compounds, and porous nanocrystals are the three types of most promising advanced nanomaterials for practical fuel cell devices, but how to integrate the three structural features into a single nanocrystal remains a huge challenge. Herein, we report an efficient one-step method to construct freestanding mesoporous Mo-doped PtBi intermetallic metallene superstructures (denoted M-PtBiMo IMSs) as highly active and stable ethylene glycol oxidation reaction (EGOR) catalysts. The materials retained their catalytic performance, even in complex direct ethylene glycol fuel cells (DEGFCs). The M-PtBiMo IMSs showed EGOR mass and specific activities of 24.0 A mgPt-1 and 61.1 mA cm-2, respectively, which were both dramatically higher than those of benchmark Pt black and Pt/C. In situ infrared spectra showed that ethylene glycol underwent complete oxidation via a 10-electron CO-free pathway over the M-PtBiMo IMSs. Impressively, M-PtBiMo IMSs demonstrated a much higher power density (173.6 mW cm-2) and stability than Pt/C in DEGFCs. Density functional theory calculations revealed that oxophilic Mo species promoted the EGOR kinetics. This work provides new possibilities for designing advanced Pt-based nanomaterials to improve DEGFC performance.

Alkali Etching of Porous PdCoZn Nanosheets for Boosting C-C Bond Cleavage of Ethylene Glycol Oxidation.

Pd-based electrocatalysts are the most effective catalysts for ethylene glycol oxidation reaction (EGOR), while the disadvantages of poor stability, low resistance to neutrophilic, and low catalytic activity seriously hamper the development of direct ethylene glycol fuel cells (DEGFCs). In this work, defect-riched PdCoZn nanosheets (D-PdCoZn NSs) with ultrathin 2D NSs and porous structures are fabricated through the solvothermal and alkali etching processes. Benefiting from the presence of defects and ultrathin 2D structures, D-PdCoZn NSs demonstrate excellent electrocatalytic activity and good durability against EGOR in alkaline media. The mass activity and specific activity of D-PdCoZn NSs for EGOR are 9.5Amg-1 and 15.7mAcm-2 , respectively, which are higher than that of PdCoZn NSs, PdCo NSs, and Pd black. The D-PdCoZn NSs still maintain satisfactory mass activity after long-term durability tests. Meanwhile, in situ IR spectroscopy demonstrates that the presence of defects attenuated the adsorption of intermediates, which improves the selectivity of the C1 pathway with excellent anti-CO poisoning performance. This work not only provides an effective synthetic strategy for the preparation of Pd-based nanomaterials with defective structures but also indicates significant guidance for optimum C1 pathway selectivity of ethylene glycol and other challenging chemical transformations.

Carbon Shell-Confined Pd-Fe Bimetallic Nanoparticles in NCNTs as Anode Catalysts for Microfluidic Direct Ethylene Glycol Fuel Cells

Carbon Shell-Confined Pd-Fe Bimetallic Nanoparticles in NCNTs as Anode Catalysts for Microfluidic Direct Ethylene Glycol Fuel Cells

An effective PtPdAuCuFe/C high-entropy-alloy applied to direct ethylene glycol fuel cells

BackgroundAs a promising green energy conversion device, direct ethylene glycol fuel cells (DEGFC) have been widely studied. But high-cost of their catalysts has severely limited large-scale commercial application. Developing economic and effective anodic electrocatalyst is an urgent work presently. MethodsHerein, an efficient high entropy alloy catalyst (HEA, penta-element) was prepared. Then, their catalytic performance and properties were authenticated by some electrochemical and physical methods. Importantly, it was also applied to a real DEGFC stack. Significant findingsNotably, the ethylene glycol oxidation current density (0.65 A mg−1PtPdAu) on as-prepared HEA is three times than that of commercial Pt/C (0.22 A mg−1Pt) with good long-term durability. Moreover, the HEA-equipped DEGFC obtains an open circuit potential of 0.58 V, which delivers 2 times larger peak power density (17.63 mW cm−2) than that of commercial Pt/C (7.37 mW cm−2). This work would be a good reference to developing other advanced HEA materials in electrocatalytic fields.

Robust poly(3,4-ethylenedioxythiophene) granules loaded Cu/Ni-doped Pd catalysts for high-efficiency electrooxidation of ethylene glycol

In our work, poly(3,4-ethylenedioxythiophene) (PEDOT) granules supported Cu/Ni-doped Pd electrocatalysts (PdCu/PEDOT and PdNi/PEDOT) were synthesized for ethylene glycol (EG) oxidation in alkaline medium. The amorphous PEDOT granules as the catalyst supports provide plenty of attachment sites for PdCu and PdNi nanoparticles. The optimized Pd1Cu3/PEDOT and Pd7Ni3/PEDOT catalysts both perform superior mass-based activity, area-based activity and intrinsic activity for EG oxidation as compared to other control samples. Moreover, chronoamperometry and long-term cyclic voltammetry tests demonstrate that the Pd1Cu3/PEDOT catalyst performs optimal anti-poisoning capability and catalytic durability. The outstanding electrocatalytic performance can be attributed to the favourable dispersion of Pd1Cu3 and Pd7Ni3 nanoparticles on the PEDOT granules and the synergistic effects between Pd, Cu/Ni atoms and the electron-rich conjugated structure of PEDOT. In summary, this work synthesized two Pd/PEDOT-based electrocatalysts with promising catalytic application prospect in direct ethylene glycol fuel cell (DEGFC), which may provide some theoretical support for the design and synthesis of competent electrocatalysts for DEGFC.

Developing a high-effective Pt-based phosphating catalyst for direct ethylene glycol fuel cells

The development of high efficiency catalysts is of pivotal importance. By introducing heteroatom phosphorus into the core-shell structure, it can optimize the electronic structure, improve the catalyst performance for direct ethylene glycol fuel cells (DEGFCs). In this study, a phosphating etched-PtCox-alloy pseudo-core-shell electrocatalyst (P-(PtCox@Pt)/C, x = 2, 4, 6, 8) is fabricated by a combined phosphating and etching method. Among as-prepared catalysts, the optimal P-(PtCo4@Pt)/C exhibits high catalytic activity for ethylene glycol electrooxidation. Furthermore, after 3000 s chronoamperometry test, its residual current density is also higher than others, indicating its good stability. Importantly, the P-(PtCo4@Pt)/C assembled-DEGFCs has an open circuit potential of 0.675 V, and peak power density of 14.48 mW cm−2. This P-(PtCo4@Pt)/C would be a good choice to developing DEGFCs technology.

Interface‐Rich Three‐Dimensional Au‐Doped PtBi Intermetallics as Highly Effective Anode Catalysts for Application in Alkaline Ethylene Glycol Fuel Cells

AbstractThe preparation of metal electrocatalysts with excellent comprehensive properties for application in alcohol fuel cells is an urgent issue. This study reports a novel 3D Au‐doped PtBi intermetallic phase woven by sub‐7 nm building blocks. The high‐efficiency “active auxiliary” Au advances the activity and in situ anti‐CO poisoning upon ethylene glycol electrooxidation on 3D PtBiAu, along with high CC bond cleavage and attainment of a ten‐electron complete electrooxidation via a CO‐free pathway. The interface‐rich 3D structure with “nanocontainer” function, electronic effect, and dual functional sites of “Pt–Au” or “Pt–Bi” enable the 3D PtBiAu to outperform industrial Pt black and 3D PtBi intermetallics significantly. The mass activity on the 3D Pt53.1Bi43.4Au3.5 intermetallics boosts to 28.72 A mgPt−1, higher than that reported in a previous study. The 3D Pt53.1Bi43.4Au3.5 exhibits superior performance to industrial Pt/C in direct ethylene glycol fuel cells (DEGFCs). The peak power density of 3D Pt53.1Bi43.4Au3.5 is 145/92 mW cm−2 in O2/air (80 °C). Importantly, the cell voltage shows a negligible decay in both O2 and air during the 20 h durability testing. This study results in the development of novel 3D PtBiAu intermetallics as high‐performance anode electrocatalysts for application in DEGFCs.

Investigating the effect of carbon support on palladium-based catalyst towards electro-oxidation of ethylene glycol

Palladium-based catalysts serve as promising electrocatalysts for the oxidation of ethylene glycol to produce electrical energy that can be used to address the continuous worldwide energy demand increments along with the depletion of fossil fuels which serve as the main energy source. For optimal catalysts performance, carbon nanotubes and carbon nanodots were investigated as palladium catalyst support materials to address difficulties in oxidizing and breaking the C–C bonds in ethylene glycol, cost of electrocatalyst, and complex reaction mechanism that is restraining rapid development and applications of direct ethylene glycol fuel cells (DEGFC). Utilization of palladium catalysts supported on carbon nanotubes (CNT) and carbon nanodots (CND) as support materials resulted in spontaneous ethylene glycol oxidation. The Pd/CNT catalyst showed greater stability compared to Pd/CND during the oxidation of ethylene glycol, and it is not easily poisoned by carbon monoxide intermediates formed during ethylene glycol oxidation as shown by a slow current decay on chronoamperometry.

Newly Found Photoactivated Pt Anchored on Three-Dimensional Layered WS2/Carbon Cloth for Highly Efficient Ethylene Glycol Electro-Oxidation

The study on ethylene glycol electro-oxidation has attracted great attention due to it as a key anode reaction in direct ethylene glycol fuel cells (DEGFCs). In this paper, layered WS2 nanosheets a...

Facile synthesis of platinum-rhodium alloy nanodendrites as an advanced electrocatalyst for ethylene glycol oxidation and hydrogen evolution reactions

Direct ethylene glycol fuel cells (DEGFCs) and water splitting devices have received intensive interest during the past few decades. However, the commonly used Pt catalysts are seriously restricted by the high cost and very low resistance to CO-like intermediates during the catalysis. Herein, a general and simple solvothermal method was developed to synthesize three-dimensional (3D) bimetallic alloyed PtRh nanodendrites (NDs) for ethylene glycol oxidation reaction (EGOR) and hydrogen evolution reaction (HER). Citric acid (CA) and cetyltrimethylammonium chloride (CTAC) played important roles in formation of such dendritic structures. The optimized Pt56Rh44 NDs displayed the greatest mass activity (MA) for EGOR in 0.5 M KOH, which was 2.6-fold higher than commercial Pt black, coupled with the remarkable increase in the HER activity with a decayed overpotential of 20.0 mV to drive a current density of 10 mA cm−2 relative to the homemade Pt41Rh59 NDs (26.2 mV), Pt81Rh19 NDs (26.2 mV), Pt black (44.3 mV), Pt/C (44.4 mV) and Rh NFs (37.3 mV). This work offers some constructive guidelines for synthesis of advanced Pt-based catalysts in such energy devices.

Polydopamine functionalized multi-walled carbon nanotubes supported PdAu nanoparticles as advanced catalysts for ethylene glycol oxidation

Design of high performance and low cost electrocatalysts for the oxidation of small organic molecules remains a great challenge for the practical application of direct fuel cells. Herein, a novel composite catalyst composed of PdAu nanoparticles (NPs) uniformly dispersed on the polydopamine functionalized MWCNTs (PDA-MWCNTs) has been synthesized. TEM images indicate that MWCNTs are successfully coated by PDA, and the as-prepared PdAu NPs are homogeneously dispersed on the PDA functional MWCNTs with smaller sizes than those on pristine MWCNTs. Electrochemical tests reveal that PDA-MWCNTs is a promising catalyst carrier for direct ethylene glycol fuel cell (DEGFC), and the PdAu(1:1)/PDA-MWCNTs catalyst displays the highest peak current density among all catalysts towards ethylene glycol oxidation reaction (EGOR) in alkaline medium, with mass activity of 1540.3 mA mgPd−1, which is 1.5, 2.6, 9.8, 13.4 and 2.0 times greater than those of PdAu(1:3)/PDA-MWCNTs, PdAu(3:1)/PDA-MWCNTs, Pd/PDA-MWCNTs, Pd/MWCNTs and commercial Pd/C catalysts, respectively. In addition, PdAu(1:1)/PDA-MWCNTs catalyst also exhibits the best stability. These findings are valuable for the development of advanced Pd-based catalysts, which will help promote the industrialization of direct fuel cell.

2D Semiconductor Bi2WO6 Nanosheets as the Pt Carriers for Ethylene Glycol Oxidation Reaction with Photoelectric Interaction

Ethylene glycol oxidation reaction (EGOR) is a key anode reaction in direct ethylene glycol fuel cells (DEGFCs). Herein, 2D semiconductor bismuth tungstate (Bi2WO6) nanosheets are facilely prepared and used as carriers for the deposition of platinum nanoparticles (Pt NPs). The resultant material is used as the working electrode in the application of DEGFCs. Due to the excellent absorption property of Bi2WO6 in visible light, the optimized Pt‐Bi2WO6 electrode (Pt at 20 wt%) shows improved catalytic activity and stability with visible‐light illumination. The current density using the Pt‐Bi2WO6 electrode reaches 492.5 mA mg−1Pt with visible‐light irradiation, which is about 4.2 fold higher in comparison with the same electrode in dark conditions. This 2D sheet‐like support, together with the visible‐light response of Bi2WO6, induces the deposition of ultra‐small sizes of Pt (5.4 nm) and the synergistic effect of electrocatalytic and photocatalytic ethylene glycol oxidation, thus greatly improving the photoelectric catalytic property of EGOR.

Monodispersed bimetallic platinum-copper alloy nanospheres as efficient catalysts for ethylene glycol electrooxidation

Designing and fabricating highly active and efficient catalysts are of vital importance for the practical applications of direct ethylene glycol fuel cells (DEGFCs). In this study, we employ a feasible one-pot synthetic method to construct highly monodispersed PtCu nanospheres (NSs) as high-efficiency anode electrocatalysts for DEGFCs. Interestingly, the optimized carbon supported Pt1Cu1 NSs can display the highest mass activity of 2146.9 mA mg−1 in 1 M KOH + 1 M EG solution under the scan rate of 50 mV s−1, which is 1.9 times higher than that of commercial Pt/C catalysts. This is ascribed to the favorable electronic effect between Pt and Cu, which is beneficial for ethylene glycol oxidation reaction (EGOR) in fuel cells. Meanwhile, such monodispersed Pt1Cu1 NSs can also exhibit excellent durability, where the Pt1Cu1 catalyst retains 62.6% of the initial value after the cyclic voltammetry of 500 cycles. This work not only provides a significant approach for designing catalysts for fuel cells, but also constructs a novel class of active and stable electrocatalysts for EGOR.

Biomass‐Derived 3D Carbon Aerogel with Carbon Shell‐Confined Binary Metallic Nanoparticles in CNTs as an Efficient Electrocatalyst for Microfluidic Direct Ethylene Glycol Fuel Cells

AbstractFlexible and 3D carbon aerogels (CAs) composed of carbon nanotubes (CNTs) with carbon shell‐confined binary palladium–nickel (Pdx–Niy) nanocatalysts on carbon fibers (Pdx–Niy/NSCNT/CA) have been developed through a facile chemical vapor deposition method. The 3D porous carbon network and the synergistic effect of carbon shell‐confined bimetal nanoparticles of rationally constructed aerogels facilitate enhanced electrocatalytic and antipoisoning activities toward ethylene glycol (EG) oxidation reaction compared to the commercial Pt/C catalyst. With the 3D morphological features and direct growth of Pd–Ni bimetallic nanoparticles encapsulated CNTs on carbon fibers, the Pd52–Ni48/NSCNT/CA delivers a maximum microfluidic direct ethylene glycol fuel cell (µDEGFC) power density and durability of, respectively, 62.8 mW cm−2 and 60 h. The superior performance observed, with Pd52–Ni48/NSCNT/CA amongst the catalysts reported in the literature, opens an exciting research avenue towards powering next‐generation, portable electronics.

Development of Sn@Pt Core-Shell Nanostructures Supported on Vulcan and N-Doped Graphene As Nanocatalysts for the Ethylene Glycol Oxidation Reaction

Direct Ethylene Glycol Fuel Cells (DEGFCs) are an attractive alternative to methanol cells, since ethylene glycol fuel (C2H6O2) is less toxic, generates more electrons during its electro-oxidation reaction and has a higher boiling point, which allows an easier handling and storage. Pt/C nanocatalysts are widely used for the Ethylene Glycol Oxidation Reaction (EGOR). However, Pt is negatively affected by the presence of reaction intermediates produced from the reaction, which are strongly bonded to Pt active sites, poisoning the nanomaterial. In view of this issue, one efficient strategy to enhance the catalytic activity and tolerance of Pt-based anodes is the design of catalysts with the addition of a co-catalyst, either as an alloy or as a core-shell nanostructure. Among the co-catalysts with appropriate physicochemical properties, Sn has been widely used to enhance the performance of Pt. In a core-shell configuration, Sn is typically the core and Pt the shell. When used as core material, Sn atoms modify the electronic and structural properties of Pt. This synergetic effect changes the binding energy of EG and intermediate species on the active sites of Pt, increasing its catalytic activity. In this work, core-shell nanocatalysts based on Sn and Pt supported on Vulcan (Sn@Pt/C) and N-doped graphene (Sn@Pt/NG) have been synthesized by the polyol method. The core-shell nanocatalysts have been tested as anode materials for the EGOR and compared with monometallic Pt/C and Pt/NG in 0.5 mol L-1 H2SO4. Electrochemical characterization by cyclic voltammetry (CV) shows that Sn@Pt/C has a higher catalytic activity than Sn@Pt/NG, Pt/C and Pt/NG for the EGOR. For example, Sn@Pt/C generates mass and specific current densities 1.3 and 3.4 times higher than Pt/C. Sn@Pt/NG also shows higher mass and specific activity than Pt/C at low overpotentials. Moreover, Sn@Pt/C and Sn@Pt/NG oxidize COads at more negative potential than the monometallic nanocatalysts. Meanwhile, the NG support shows a positive metal-support effect, since Pt/NG is more tolerant to COads than Pt/C. In conclusion, Sn@Pt core-shell nanocatalysts are an attractive alternative for the EGOR, due to their higher catalytic activity and tolerance to COads than monometallic Pt.

An alkaline direct ethylene glycol fuel cell with an alkali-doped polybenzimidazole membrane

An alkaline direct ethylene glycol fuel cell (DEGFC) with an alkali-doped polybenzimidazole membrane (APM) is developed and tested. It is demonstrated that the use of APMs enables the present fuel cell to operate at high temperatures. The fuel cell results in the peak power densities of 80 mW cm−2 at 60 °C and 112 mW cm−2 at 90 °C, respectively. The power output at 60 °C is found to be 67% higher than that by DEGFCs with proton exchange membranes, which is mainly attributed to the superior electrochemical kinetics of both ethylene glycol oxidation and oxygen reduction reactions in alkaline media.

Synthesis of Unsupported Pt-based Electrocatalysts and Evaluation of Their Catalytic Activity for the Ethylene Glycol Oxidation Reaction

In this work, unsupported Pt, Pt-Ru (1:1 wt. % Pt:Ru ratio) and Pt-CeO2 (1:1 wt. % Pt:CeO2 ratio) electrocatalysts were synthesized and evaluated as anodes for the ethylene glycol oxidation reaction (EGOR) in out in H2SO4 electrolyte. The nanomaterials were prepared by slowly dropping the precursors in a NaBH4 solution, in a reduction process of 10 min. Analysis by XRD showed the formation of polycrystalline electrocatalysts, while the chemical composition characterization indicated a ratio between the different elements in the bimetallic materials close to the stoichiometric value. Selected area electron diffraction patterns evaluation carried out in the TEM apparatus helped in the identification of Pt (1 1 1) in the three anodes, Ru (1 0 0) in Pt-Ru, and CeO2 (1 1 1) in Pt-CeO2, confirming the formation of Ru and CeO2 phases. The results from the electrochemical characterization by Linear Scan Voltammetry (LSV) showed that the Pt-Ru material possess a higher mass catalytic activity for the EGOR, followed Pt-CeO2, compared to Pt-alone. The nano-sized Pt-Ru and Pt-CeO2 anodes demonstrated a high electrochemical stability in accelerated potential cycling tests, with very low surface area losses in the hydrogen adsorption/desorption region after 500 polarization cycles. The results indicated that the bimetallic electrocatalysts are candidate anodes for Direct Ethylene Glycol Fuel Cells.

Electrooxidation of Ethylene Glycol and Glycerol on Pd‐(Ni‐Zn)/C Anodes in Direct Alcohol Fuel Cells

The electrooxidation of ethylene glycol (EG) and glycerol (G) has been studied: in alkaline media, in passive as well as active direct ethylene glycol fuel cells (DEGFCs), and in direct glycerol fuel cells (DGFCs) containing Pd-(Ni-Zn)/C as an anode electrocatalyst, that is, Pd nanoparticles supported on a Ni-Zn phase. For comparison, an anode electrocatalyst containing Pd nanoparticles (Pd/C) has been also investigated. The oxidation of EG and G has primarily been investigated in half cells. The results obtained have highlighted the excellent electrocatalytic activity of Pd-(Ni-Zn)/C in terms of peak current density, which is as high as 3300 A g(Pd)(-1) for EG and 2150 A g(Pd)(-1) for G. Membrane-electrode assemblies (MEA) have been fabricated using Pd-(Ni-Zn)/C anodes, proprietary Fe-Co/C cathodes, and Tokuyama A-201 anion-exchange membranes. The MEA performance has been evaluated in either passive or active cells fed with aqueous solutions of 5 wt % EG and 5 wt % G. In view of the peak-power densities obtained in the temperature range from 20 to 80 °C, at Pd loadings as low as 1 mg cm(-2) at the anode, these results show that Pd-(Ni-Zn)/C can be classified amongst the best performing electrocatalysts ever reported for EG and G oxidation.