Methanol Tolerant PWA-Pt/C Catalyst with Excellent Electrocatalytic Activity for Oxygen Reduction in Direct Methanol Fuel Cell

It was reported for the first time that phosphorictungstenic acid （PWA） could promote the oxygen reduction reaction （ORR） and inhibit the methanol oxidation reaction at the cathodic Pt/C catalyst in the direct methanol fuel cell （DMFC）. When the weight ratio of PWA to Pt/C is 1, the composite catalyst increases the reduction current of oxygen by about 38% and decreases the oxidation current of methanol by about 76% compared with that of the Pt/C catalyst.

FeNC Catalysts with High Catalytic Activity and Stability for Oxygen Reduction Reaction

Although Pt-based catalysts have been considered as the most effective electrocatalyst for the cathodic oxygen reduction reaction(ORR) of direct methanol fuel cells(DMFCs), they still suffer from the drawbacks of high cost, poor long-term stability and methanol/CO poisoning effects. Thus, developing low-cost ORR catalysts with high efficiency, durability and antipoisoning ability is of paramount importance. Herein, a series of non-noble metal FeNC materials are prepared through a facile pyrolysis process and used as the electrocatalysts toward ORR in alkaline electrolyte. Results show that the FeNC-800-1h catalyst pyrolyzed at 800 ℃ for 1 h with the mass ratio of Fe(NO)·6HO to melamine being 0.50 exhibits the highest catalytic performance among the as-prepared FeN C catalysts. The half-wave potential of ORR is ca. 0.81 V, which is only 38 m V lower than that on the noble metal Pt/C catalyst. Besides, it also displays higher stability and methanol tolerance than Pt/C. There is almost no change in the current during the chronoamperometric test when methanol is added in the electrolyte whereas significant decrease is found on Pt/C catalyst. This study of FeN C catalysts provides new insights on understanding the ORR mechanism and suggests a promising strategy to develop low-cost and highly efficient non-noble metal electrocatalysts for ORR.

直接甲醇燃料电池的耐甲醇阴极电催化剂炭载四羧基酞菁钴的研究

比较了甲醇对 Pt/C和炭载四羧基酞菁钴 (Co Pc Tc/C)催化氧还原性能的影响 .结果表明 ,甲醇使Pt/C催化氧还原的性能严重降低 ,而对经 80 0℃热处理的 Co Pc Tc/C(Co Pc Tc/C-80 0 )基本没有影响 ;并且Co Pc Tc/C-80 0催化氧还原的性能优于经其它温度热处理的 Co Pc Tc/C,Co Pc Tc/C-80 0是一种较好的直接甲醇燃料电池的耐甲醇阴极电催化剂 .XPS结果表明 ,Co Pc Tc/C-80 0的活性位可能是含 Co N4结构的物质和零价 Co的混合物 .

M_cPt_s纳米催化剂的电催化氧还原性能

采用两步化学还原法合成不同Pt壳层厚度的M_cPt_s(M=Ni、Co、Cu和Ag)纳米粒子,用XRD、XPS和TEM测试分析粒子的结构和组成,动电位扫描法测试对氧还原反应的活性和抗甲醇性能。M_cPt_s纳米粒子为球形,平均粒径为35 nm,Pt壳层平均厚度约6 nm;相对于Pt/C,当M为Ni、Co时,氧还原活性提高,当M为Cu、Ag时,氧还原活性降低;Co、Cu和Ag为核芯,还可提高M_cPt_s/C的抗甲醇性能。

阴离子膜直接甲醇燃料电池阴极氧电还原研究

阴离子膜直接甲醇燃料电池(AEM-DMFC)采用碱性体系,阴阳极反应环境优越,反应过电位较低,电渗析与甲醇渗透方向相反,甲醇进入阴极的速率较小,电池功率密度和发电效率明显高于质子膜直接甲醇燃料电池(PEM-DMFC)。碱性条件下,阴极氧还原电催化材料的研究和应用多集中于Pt/C和Ag/C,因其活性和抗甲醇性不足,反应过电位较高,AEM-DMFC的优势并未得到充分体现,因此开发新型阴极电催化剂成为提高AEM-DMFC性能的关键问题。