# Progress in the Development of Electrodeposited Catalysts for Direct Liquid Fuel Cell Applications
## 3 Electrodeposition on Non-Carbon Substrates  
Though sp\({}^{3}\) bonded carbons such as Vulcan, CNT, carbon fibres, etc., possess good surface area with electronic conductivity, they are often prone to corrosion with an microstructural degradation during cyclic anodic polarization leading to an activity loss and catalyst particles detachment from the support [57, 58, 59]. Thus, the development of advanced and more stable supporting material remains to be of particular interest for improving the noble metal particle dispersion. [PERSON] et al. [60] explored the feasibility of depositing Pt on metallic and non-metallic electrodes such as tungsten, titanium, zirconium, rhenium, stainless steel, glassy carbon, and polyaniline. The studies revealed that tungsten, titanium, and glassy carbon were effective substrates for conducting preliminary nucleation and growth investigations for Pt deposition. [PERSON] et al. [61] synthesised Pd nanostructures at two different potentials  
Figure 4: X-ray diffractograms of pure carbon paper and Pd deposited over GO–CP substrate. Reprinted with permission from [56]. and concentrations of palladium (II) sulphate (PdSO4) solution on carbon substrates: highly oriented pyrolytic graphite and glassy carbon. The influence of the electrodeposition conditions on the topography of the carbon substrate and morphology of the deposited Pd were studied. The authors demonstrated that the electrodeposition conditions influenced the morphological characteristics and size distribution of the Pd nanostructures, and highlighted the potential applications of the Pd nanostructures in electrocatalysis and nanotechnology. Noncarbon supports, such as metal oxides (TiO2, Indium tin oxides) and Ti-nitrides (TiN) [62, 63], show better corrosion resistance and high melting points but are characterized by lower electrical conductivity. In addition, this group of support materials has a range of other advantages that carbon materials do not have. Few reviews [64, 65] detailed research and development on several distinct classes of innovative support materials for DLFCs, including conductively doped diamonds, nanodiamonds, conductive oxides of tin, indium tin, titanium, tungsten, and carbides (tungsten carbides). The benefits, drawbacks, action mechanisms, and strategies to improve the electro-catalytic performance in terms of durability, stability were discussed briefly. Moreover, approaches to improve the current catalytic support materials were also discussed. For instance, titanium-based support materials lead to higher CO tolerance than carbon support catalysts, but they are not used as often as carbon materials because their high molecular weight, which lowers the mass activity of the catalyst. These are being used when their advantages are more noteworthy than the disadvantages of their presence [66, 67]. [PERSON] [68] reported the formation of noble metal Pt/TiO2 and Pd/TiO2 smooth bead arrays with well dispersion by multiple polarization of fresh Ti in aqueous solutions containing Pt, Pd using potentiodynamic deposition technique. Potentiodynamic deposition of noble metals such as Pt, Pd, Au, and Ag on Ti surface to form metal/oxide layers is considered to be one of the most straightforward approaches to form metal/oxide layers. Electrodeposition of noble metals is generally motivated by the formation of TiO2. Titanium in aqueous solutions forms a stable TiO2, which acts as a self-template for the deposition of noble metals. The advantage of using this method is that TiO2 will prevent the agglomeration of nano particles by acting as a self-template which is believed to enhance the real surface area. The noble metal nanoparticles are reported to be distributed along the TiO2 surface under potentiodynamic conditions. At the initial stages of potential cycling, the growth of noble metal nanoparticles was shown to be favoured in relation to TiO2 growth.