Dehghani Sanij Fereshteh, Balakrishnan Prabhuraj, Su Huaneng, Khotseng Lindiwe, Xu Qian
Institute for Energy Research, Jiangsu University Zhenjiang 212013 China
Department of Chemistry, University of the Western Cape Cape Town 7535 South Africa.
RSC Adv. 2021 Dec 7;11(62):39118-39129. doi: 10.1039/d1ra06936e. eCollection 2021 Dec 6.
Designing advanced nanocatalysts for effectively catalyzing the oxygen reduction reaction (ORR) is of great importance for practical applications of direct methanol fuel cells (DMFCs). In this work, the reduced graphene oxide (rGO)-supported palladium-nickel (Pd-Ni/rGO) alloy modified by the novel polyoxometalate (POM) with Keggin structure (Pd-Ni/rGO-POM) is efficiently fabricated an impregnation technique. The physical characterizations such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP-OES), field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (FESEM-EDX), and transmission electron microscopy (TEM) are utilized to confirm the structure, morphology, and chemical composition of the fabricated samples. The XRD results verify the formation of the POM-modified PdNi/rGO alloy electro-catalyst with the face-centered-cubic (fcc) structure and average crystallite size of 5.54 nm. The electro-catalytic activities of the nanocatalysts towards ORR in alkaline conditions are evaluated by cyclic voltammetry (CV), rotating disk electrode (RDE), and chronoamperometry (CA) analyses. The synthesized PdNi/rGO-POM nanomaterial shows remarkably greater ORR catalytic activity and better methanol resistance compared with the PdNi/rGO and Pd/rGO electro-catalysts. The promoted ORR activity of the PdNi/rGO-POM sample is attributed to the alloying of Pd and Ni components, the uniform scattering of Pd-Ni nanoparticles on rGO, and the alloyed catalyst being modified with POM. Moreover, these findings demonstrate that the resultant PdNi/rGO-POM material is attractive as a suitable and cost-effective cathodic catalyst for DMFCs, in which the decorated POMs play a vital role for the enhancement in the catalytic abilities of the nanocatalyst.
设计能够有效催化氧还原反应（ORR）的先进纳米催化剂对于直接甲醇燃料电池（DMFC）的实际应用具有重要意义。在这项工作中，通过浸渍技术高效制备了由具有Keggin结构的新型多金属氧酸盐（POM）修饰的还原氧化石墨烯（rGO）负载的钯 - 镍（Pd - Ni/rGO）合金（Pd - Ni/rGO - POM）。利用X射线衍射（XRD）、傅里叶变换红外光谱（FT - IR）、拉曼光谱、电感耦合等离子体发射光谱（ICP - OES）、场发射扫描电子显微镜结合能量色散X射线光谱（FESEM - EDX）和透射电子显微镜（TEM）等物理表征手段来确定所制备样品的结构、形态和化学成分。XRD结果证实形成了具有面心立方（fcc）结构且平均晶粒尺寸为5.54 nm的POM修饰的PdNi/rGO合金电催化剂。通过循环伏安法（CV）、旋转圆盘电极（RDE）和计时电流法（CA）分析评估了纳米催化剂在碱性条件下对ORR的电催化活性。与PdNi/rGO和Pd/rGO电催化剂相比，合成的PdNi/rGO - POM纳米材料表现出显著更高的ORR催化活性和更好的抗甲醇性能。PdNi/rGO - POM样品ORR活性的提高归因于Pd和Ni组分的合金化、Pd - Ni纳米颗粒在rGO上的均匀分散以及合金催化剂被POM修饰。此外，这些发现表明所得的PdNi/rGO - POM材料作为DMFC合适且具有成本效益的阴极催化剂具有吸引力，其中修饰的POM对纳米催化剂催化能力的增强起着至关重要的作用。
