Gram-Scale Synthesis of CoO/C as Base for PtCo/C High-Performance Catalysts for the Oxygen Reduction Reaction

Abstract

The composition, structure, catalytic activity in the ORR and stability of PtCo/C materials, obtained in two stages and compared with commercial Pt/C analogs, were studied. At the first stage of the synthesis performed by electrodeposition of cobalt on a carbon support, a CoOx/C composite containing 8% and 25 wt% cobalt oxide was successfully obtained. In the second step, PtCoOx/C catalysts of Pt1.56Co and Pt1.12Co composition containing 14 and 30 wt% Pt, respectively, were synthesized based on the previously obtained composites. According to the results of the composition and structure analysis of the obtained PtCoOx/C catalysts by X-ray diffraction (XRD), X-ray fluorescence analysis (XRF), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) methods, the formation of small bimetallic nanoparticles on the carbon support surface has been proved. The resulting catalysts demonstrated up to two times higher specific catalytic activity in the ORR and high stability compared to commercial Pt/C analogs.

New Approach to Synthesizing Cathode PtCo/C Catalysts for Low-Temperature Fuel Cells

“…When further synthesizing the ST-3 and ST-3(AT) materials, as a result of doubling the amount of the metal component, the contribution of the support to the electric double layer capacitance appeared to decrease, which was reflected in a decrease in the double-layer region currents. An additional peak in the potential range of 0.7-0.8 V can be observed in the CV of the ST-2 material, which may be associated with the presence of cobalt oxide [41]. The ESA value varied in the following order: ST-2 < ST-3 ≤ JM40 < ST-3(AT) (Table 2).…”

“…The analysis of the above data allowed them to draw the conclusion that the borohydride and polyol synthesis methods make it possible to obtain crystallites with the smallest particle size (≈2.5 nm) compared with the other ones considered in the review. Previously, we have proposed an alternative method to synthesize PtCo/C catalysts that differs from most of the one-step liquid-phase synthesis methods described in the literature due to the presence of a preliminary stage for the electrochemical preparation of a composite Co x O y /C support [40,41]. In this regard, the PtCo/C materials synthesized with the twostep method based on an electrochemically prepared composite Co x O y /C support with subsequent platinum deposition demonstrated up to two times greater specific catalytic ORR activity compared with commercial Pt/C analogs [41].…”

The PtM/C (M = Co, Ni, Cu, Ru) Electrocatalysts: Their Synthesis, Structure, Activity in the Oxygen Reduction and Methanol Oxidation Reactions, and Durability

“…The synthesis of the composite CoO x /C materials was carried out by the electrochemical deposition of cobalt on particles of the carbon support from the electrolyte with the following composition: CoSO 4 •7H 2 O-500 g/L, NaCl-15, and H 3 BO 3 -45, in a specially designed cell, as described in detail in [28]. When passing the current through the cell, the metal was deposited on the surface of carbon particles in the suspension, with the working surface being constantly modified due to the diffusion and mixing processes and the evolution of gaseous hydrogen [28]. This technique made it possible to obtain a support with an oxide mass fraction of 8%.…”

“…The search for optimal compositions and microstructures is still ongoing, which in turn causes the development of different methods to obtain PtM/C catalysts [1,8,19,20]. When obtaining high-performance ORR catalysts, Ni [21][22][23][24][25], Co [26][27][28][29][30], and Cu [31][32][33][34][35][36][37] are the most commonly used alloying components for platinum among other metals [38,39]. The use of ruthenium as the alloying component for platinum is connected to another type of influence that is different from that for nickel, cobalt, and copper.…”