Ni-Co bimetal decorated carbon nanotube aerogel as an efficient anode catalyst in urea fuel cells

Abstract

Ni-based catalysts have been considered as an efficient anode material for urea fuel cells due to the low cost and high activity in alkaline media. Herein, we demonstrate that Ni-Co bimetallic nanoparticles decorated carbon nanotube aerogels as catalysts for urea oxidation reaction (UOR) can be synthesized by a polyol reduction and sol-gel method. The morphology, structure, and composition of the Ni-Co/MWCNT aerogels were characterized by scanning electron microscopy and X-Ray diffraction. The electro-catalytic activity of the Ni-Co/MWCNT aerogels towards UOR was investigated using cyclic voltammetry. It was found that the Co-doping at 25% (Co/Ni) significantly increased the oxidation peak current and reduced the overpotential of the UOR. Furthermore, the MWCNT aerogel support also remarkably enhanced electro-catalytic activity by providing a high surface area and fast mass transport for the UOR owing to the porous 3D network structures with uniform distribution of Ni-Co nanoparticles. Urea/O2 fuel cell with Ni-Co/MWCNT aerogel as anode material exhibited an excellent performance with maximum power density of 17.5 mWcm−2 with an open circuit voltage of 0.9 V. Thus, this work showed that the highly porous three-dimensional Ni-Co/MWCNT aerogel catalysts can be used for urea oxidation and as an efficient anode material for urea fuel cells.

Metal–organic framework–derived Ni@C and NiO@C as anode catalysts for urea fuel cells

“…A commercial Pt/C (40 wt%, E-TEK)-coated carbon paper with a Pt loading of 0.6 mg cm −2 was used as a cathode. An anion exchange membrane (AEM; Fumasep FAA-3-PK-130, Germany) was used as a polymer electrolyte separating anode and cathode compartments, as described elsewhere 48 . The active electrode area equaled 5.0 cm 2 .…”

Aerogels: promising nanostructured materials for energy conversion and storage applications

“…Reproduced with permission from [146] Page 19 of 27 7 have been considered as an efficient anode material for urea fuel cells due to their low cost and high activity towards the urea oxidation reaction. Ni and Co bimetal doped CNT aerogel as an anode electrocatalyst exhibited a maximum power density of 17.5 mW/cm 2 and an open-circuit voltage of 0.9 V [149]. Here, the metals increased the oxidation peak current and decreased the overpotential of the urea oxidation reaction.…”

A Remarkable Class of Nanocomposites: Aerogel Supported Bimetallic Nanoparticles

“…Resulting multicomponent sol undergoes condensation/gelation reactions, Another technique of producing aerogel supported bimetallic NPs is the utilization pre-formed colloidal NPs, which are synthesized via reduction of MPs in a solution by the help of a reducing agent with or without stabilizing agents, depending on precursor and reducing agent properties (Reetz, 2007). Colloidal NPs can be introduced to the sol either before (Route C in Figure 2) or after (Route D in Figure 2) hydrolysis (Vallribera and Molins, 2008;Sadrieyeh and Malekfar, 2018a,b;Tesfaye et al, 2019). A similar procedure to Route C was reported by Da Silva et al (2015) for Pt/rGO/TA (Pt multilayer reduced graphene oxide TA) synthesis.…”

“…CAs are mesoporous materials with enriched porosity and high specific surface areas, making them favorable for many practical applications (Thirumalraj et al, 2018;Tesfaye et al, 2019). They are generally produced by pyrolysis of organic aerogels.…”

“…CoNi alloy NPs with a core-shell hierarchical structure covered with graphitized carbon materials were observed in TEM images. NiCo/MWCNT (multiwalled carbon nanotube) was fabricated by a polyol reduction method starting with nickel(II) chloride and cobalt(II) chloride (Tesfaye et al, 2019). NiCo/MWCNT/PVAA (polyvinyl alcohol aerogel) was produced by mixing PVA solution with NiCo/MWCNT powder and freeze drying of the resulting hydrogels.…”