RESUMO
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.
RESUMO
Improving the electrocatalytic performance by modulating the surface and interface electronic structure of noble metals is still a research hotspot in electrocatalysis. Herein, we prepared the heterogeneous catalyst based on the well-dispersed PdCu nanoalloy and the N-doped Ti3C2Tx MXene support (PdCu/N-Ti3C2Tx) via in situ growth of PdCu nanoparticles on the fantastic N-Ti3C2Tx sheets. By exploring the electrocatalytic properties of ethanol oxidation reaction (EOR), the composition optimized Pd1Cu1/N-Ti3C2Tx delivers higher mass activity/specific activity/intrinsic activity (2200.7 mA mgPd-1/13.1 mA cm-2/2.2 s-1), anti-poisoning ability and stability than those of Pd/N-Ti3C2Tx, Pd1Cu1/Ti3C2Tx and commercial Pd/C, which can be attributed to the modified surface electronic features of Pd by the participation of Cu atoms and N-Ti3C2Tx MXene, as well as the "metal-carrier" effect between the PdCu nanoalloy and N-Ti3C2Tx heterogeneous interface. Furthermore, the conductivity of N-Ti3C2Tx MXene can be improved by N-doping, and the abundant terminal groups (-O, -OH, -F and N) on the N-Ti3C2Tx surface can promote the electron exchange between PdCu and N-Ti3C2Tx. This work provides an effective strategy for engineering heterogeneous electrocatalysts for enhanced electrocatalytic EOR by adjusting the interfacial electronic structure of noble metals.
RESUMO
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.
Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes , Polímeros , Compostos Bicíclicos Heterocíclicos com Pontes/química , Catálise , Etilenoglicóis , Polímeros/químicaRESUMO
Bio-based coating materials were prepared from epoxidized soybean oil as a renewable source. Acetoacetylated soybean oil was synthesized by the ring-opened and transesterification reaction of epoxidized soybean oil, and its chemical structure was characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and rheometric viscosity analyses. On the basis of acetoacetylated soybean oil, several bio-based coating materials were prepared using different aromatic dicarboxaldehydes (1,2-benzenedialdehyde, 1,3-benzenedialdehyde, 1,4-phthalaldehyde, 4,4'-biphenyldicarboxaldehyde) and characterized. The resulting films possess good performance, including the highest glass transition temperature of 54 °C, a Young's modulus of 24.91 MPa, tensile strength of 5.65 MPa, and an elongation at break of 286%. Thus, this work demonstrates the Knoevenagel condensation reaction, which is based on soybean oil as a potential newer eco-friendly raw material.