الفهرس 
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Abstract
Energy is one of the big problems face humans today, due to the depletion of petroleum-based energy resources and its environmental impact and limitations (i.e., low efficiency and climate change; greenhouse effect). In this regards, intense research has focused on alternative energy technologies that can reduce the dependence on fossil fuels. FCs have received much attention in recent years owing to their broad range of benefits such as energy security, environmental benefits, domestic economy, high efficiencies, and low emissions Fuel flexibility (domestic, clean, and renewable fuels). This study is focused on tailoring an efficient binary catalyst for formic acid and methanol oxidation reaction (FAOR and MOR).
In this thesis, the first chapter introduces a general introduction about energy crisis and their impact to our environment using several statistical data analysis. Then, the chapter was directed to focus on the FCs technologies including their history, benefits, components, and types. This followed by studying the FAOR and MOR at Pt and/or Pd based catalysts with referring to the mechanisms of enhancement in these catalysts.
The second chapter shows the methodology of the experiments, the
Thesis Summary
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catalysts fabrication techniques, chemicals used in thesis work, and the characterization devices that were used to discover surface morphology, composition, and crystal structure of our proposed catalysts. These devices include FE-SEM, EDS, XRD, and ICP. Also, the device used in our electrochemical measurement was mentioned with details in this chapter.
The third chapter discusses the results and discussion of ”Palladium/Gold binary metallic anodic catalyst for highly efficient and durable formic acid fuel cells”. This chapter concludes that the Pd1Au1 catalyst acquired the highest catalytic activity (in terms of the highest peak current density (Ip) 4.16 mA cm−2 compared to 0.33 mA cm−2 obtained at the Pd1Au0 catalyst) and stability (19 times higher current density after 3600 s of continuous electrolysis compared with the Pd1Au0 catalyst) toward FAOR. The CO stripping and impedance measurements confirmed both the third body and the electronic effects as the mechanisms of catalytic enhancement.
The fourth chapter discusses the results and discussion of ”Electrocatalysis of formic acid at Pt/NiOx modified electrodes”. This chapter concludes that the sequential (layer-by-layer) electrodeposition strategy was efficient for the fabrication of NiOx/Pt/GC binary catalyst toward EOFA. This catalyst sustained a higher catalytic activity with up to ca. 3 times increase in the Ipd/Ipind index and
Thesis Summary
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p
p p
ca. 2 times increase in the Ipd/I b index toward EOFA. Moreover, it showed an improved stability toward EOFA after continuous electrolysis for 30 min at which it has a higher current density (by ca. 2.5 times) than that obtained at the unmodified Pt/GC. The mechanism of enhancement of this catalyst may arise from the bifunctional effect of NiOx which able to reduce and/or mitigate the COads.
The fifth chapter discusses the results and discussion of ”Co- electrodeposited PtPd anodic catalyst for the direct formic acid fuel cells”. This chapter concludes that the PtPd/GC binary catalyst was endorsed for efficient FAOR. The PtPd catalyst retained the highest catalytic activity (with up to ca.
12.4 times increase in the Ipd/I ind index, 2 times increase in the Ipd/I b index and
–91 mV shift in Eonset) of FAOR. This associated a critical improvement in the catalytic stability that appeared in maintaining a higher (by ca. 2.5 times) current density after prolonged electrolysis for 3600 s at 0.2 V. It was thought that minimizing the CO adsorption at the Pt surface was mostly behind the observed enhancement.