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Electrocatalysis of oxygen reduction when varying the mass ratio of metal nanoparticles to carbon support for catalysts with a 10 to 10 to 80 mol% of Pt and Pd on Ag
International Journal of Hydrogen Energy ( IF 7.2 ) Pub Date : 2018-07-06 , DOI: 10.1016/j.ijhydene.2018.06.086
I.E. Pech-Pech , Dominic Gervasio , S.A. Aguila , J.F. Perez-Robles

The reduction of total Pt-loading in a cathode catalyst without sacrificing performance is one of the key objectives for the large-scale commercialization of proton exchange membrane fuel cell (PEMFC) technology. A core-shell type nanostructured catalyst with a Pt-loading 20 times lower than a commercial catalyst is demonstrated herein to be more active for the electrocatalysis of the oxygen reduction reaction (ORR) in acid electrolyte. The weight ratio of metal nanoparticles on carbon support is the key to achieving the highest ORR activity in a series of silver-based catalysts, all with 10 mol percent of Pt and 10 mol percent of Pd over 80 mol percent of silver (Ag) and supported on untreated Vulcan carbon to form an electrocatalyst ([email protected]10Pd10/C) with either 5, 10, 20 or 30 wt% of total metals on carbon; which correspond to a Pt concentration around 1, 2, 3 and 5 wt%, respectively. All metal nanostructures on carbon show a similar morphology, size and structure. Thin films of these four [email protected]10Pd10/C catalysts on rotating disk electrodes (TF-RDEs) all shown a 4-electrons pathway for the ORR and give higher exchange current densities (jo > 3.8 mA/cm2) than a commercial Etek Pt20/C catalyst (jo = 2.4 mA/cm2). The [email protected]10Pd10/C catalyst with 5 wt% of total metals (1 wt% of Pt) on carbon gives the best electrocatalysis; reducing molecular oxygen to water two times faster and generating 25% higher current per milligram of platinum (mass activity) than the commercial catalyst (Pt20/C). Therefore, the [email protected]10Pd10/C catalyst with 5 wt% of total metals is a new catalyst for ORR for a PEMFC with a lower Pt loading and cost.



中文翻译:

当在Ag上具有10到10至80 mol%的Pt和Pd的催化剂改变金属纳米颗粒与碳载体的质量比时,氧还原的电催化

在不牺牲性能的情况下减少阴极催化剂中总Pt负载是质子交换膜燃料电池(PEMFC)技术大规模商业化的关键目标之一。Pt负载量比市售催化剂低20倍的核-壳型纳米结构催化剂在本文中被证明对于酸性电解质中的氧还原反应(ORR)的电催化具有更高的活性。碳载体上金属纳米颗粒的重量比是在一系列基于银的催化剂中获得最高ORR活性的关键,所有这些催化剂都含有10 mol%的Pt和10 mol%的Pd超过80 mol%的银(Ag)和负载在未经处理的Vulcan碳上以形成电催化剂([受电子邮件保护] 10 Pd 10/ C),碳中金属总量的5、10、20或30 wt%;它们分别对应于大约1、2、3和5 wt%的Pt浓度。碳上的所有金属纳米结构都表现出相似的形态,大小和结构。旋转圆盘电极(TF-RDE)上的这四种[受电子邮件保护] 10 Pd 10 / C催化剂的薄膜都显示出ORR的4电子途径,并具有更高的交换电流密度(j o  > 3.8 mA / cm 2)比市售Etek Pt 20 / C催化剂(j o  = 2.4 mA / cm 2)。[受电子邮件保护] 10 Pd 10在碳上具有5 wt%的总金属(Pt的1 wt%)的/ C催化剂可产生最佳的电催化作用;与商业催化剂(Pt 20 / C)相比,将分子氧还原为水的速度快两倍,每毫克铂产生的电流(质量活性)高25%。因此,具有5 wt%的总金属的[受电子邮件保护的] 10 Pd 10 / C催化剂是用于PMFC负载和成本较低的PEMFC的ORR的新型催化剂。

更新日期:2018-07-06
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