PdPt bimetallic catalysts that employ CeO2-modified carbon black as a support have been prepared using an organic colloidal method.PdPt/CeO2-C shows excellent performance toward the anodic oxidation of formic acid.The...PdPt bimetallic catalysts that employ CeO2-modified carbon black as a support have been prepared using an organic colloidal method.PdPt/CeO2-C shows excellent performance toward the anodic oxidation of formic acid.The effects of varying both Pd to Pt ratio and CeO2 content have been investigated.The optimal Pd to Pt atomic ratio is 15,indicating that addition of small amounts of Pt can significantly enhance the activity of the catalyst.When the CeO2 content in the catalyst reaches as high as ～15 wt.%,the catalyst shows the maximum activity.Adding CeO2 not only enhances the catalytic activity of the material,but may also change the mechanism of its catalysis of the anodic oxidation of formic acid.Pd15Pt1/15CeO2-C exhibited 60% higher activity than Pd/C,and had a negative shift in onset potential of more than 0.1 V.Based on characterization by X-ray diffraction,X-ray photoelectron spectroscopy,thermogravimetric analysis and transmission electron microscopy,the interactions between the components are revealed and discussed in detail.展开更多
In this work, the excess water-stagnation issue in the high current region in direct methanol fuel cells(DMFCs) is resolved by using atomic precision modulated nitrogen-crafted graphene(NG) in the cathode microporous ...In this work, the excess water-stagnation issue in the high current region in direct methanol fuel cells(DMFCs) is resolved by using atomic precision modulated nitrogen-crafted graphene(NG) in the cathode microporous layer by utilizing simplistic,industrial-expansive and ecological strategy. Few-layer 2D-graphene(~2–5 nm thickness) is prepared by bath sonication approach from abundant feedstock-graphite and is treated with nitric acid to yield 1.8 wt.% uniformly dispersed nitrogen containing NG. Specifically, 1:4 weight ratio NG:carbon-black(CB) hybrid architecture, displays 0.252 V in 370 mA cm^(-2) with the peak power density of 93.4 mW cm^(-2), improving cell power density by 45.6% compared with standard one at 60℃ and 1 mol/L methanol/oxygen conditions at ultra-low catalyst loadings and displaying exceptional stability. Atomic insights into NG reveal that interplay between bonding configurations, altered hydrophobic/hydrophilic porosity of graphene(10.6% less wettability from contact angle and 13.1% high electrode porosity measurements) contribute to the better mass-transport-porogenic effect(16.3% high oxygen-permeability), mildly affecting the electron pathway(6.5% reduced in-plane electrical conductivity),overall significantly improving cell performance. Altogether, this work delivers multiple advantages, i.e., the usage of material from facile, sustainable and cost-effective routes, while improving DMFC performance with potential industrial promise.展开更多
基金supported by the National Natural Science Foundation of China (20673040 and 20876062)the Ministry of Science and Technology of China (2009AA05Z119)the Guangdong Provincial Scientific Foundation (36055)
文摘PdPt bimetallic catalysts that employ CeO2-modified carbon black as a support have been prepared using an organic colloidal method.PdPt/CeO2-C shows excellent performance toward the anodic oxidation of formic acid.The effects of varying both Pd to Pt ratio and CeO2 content have been investigated.The optimal Pd to Pt atomic ratio is 15,indicating that addition of small amounts of Pt can significantly enhance the activity of the catalyst.When the CeO2 content in the catalyst reaches as high as ～15 wt.%,the catalyst shows the maximum activity.Adding CeO2 not only enhances the catalytic activity of the material,but may also change the mechanism of its catalysis of the anodic oxidation of formic acid.Pd15Pt1/15CeO2-C exhibited 60% higher activity than Pd/C,and had a negative shift in onset potential of more than 0.1 V.Based on characterization by X-ray diffraction,X-ray photoelectron spectroscopy,thermogravimetric analysis and transmission electron microscopy,the interactions between the components are revealed and discussed in detail.
基金supported by China Postdoctoral Science Foundation(Grant No.2019M661749)Six-Talent-Peaks Project in Jiangsu Province(Grant No.2016-XNY-015)+1 种基金the High-Tech Key Laboratory of Zhenjiang City(Grant No.SS2018002)Priority Academic Program Development(PAPD) of Jiangsu Higher Education Institutions。
文摘In this work, the excess water-stagnation issue in the high current region in direct methanol fuel cells(DMFCs) is resolved by using atomic precision modulated nitrogen-crafted graphene(NG) in the cathode microporous layer by utilizing simplistic,industrial-expansive and ecological strategy. Few-layer 2D-graphene(~2–5 nm thickness) is prepared by bath sonication approach from abundant feedstock-graphite and is treated with nitric acid to yield 1.8 wt.% uniformly dispersed nitrogen containing NG. Specifically, 1:4 weight ratio NG:carbon-black(CB) hybrid architecture, displays 0.252 V in 370 mA cm^(-2) with the peak power density of 93.4 mW cm^(-2), improving cell power density by 45.6% compared with standard one at 60℃ and 1 mol/L methanol/oxygen conditions at ultra-low catalyst loadings and displaying exceptional stability. Atomic insights into NG reveal that interplay between bonding configurations, altered hydrophobic/hydrophilic porosity of graphene(10.6% less wettability from contact angle and 13.1% high electrode porosity measurements) contribute to the better mass-transport-porogenic effect(16.3% high oxygen-permeability), mildly affecting the electron pathway(6.5% reduced in-plane electrical conductivity),overall significantly improving cell performance. Altogether, this work delivers multiple advantages, i.e., the usage of material from facile, sustainable and cost-effective routes, while improving DMFC performance with potential industrial promise.
