Nitrogen Doped Ordered Mesoporous Carbon as Support of PtRu Nanoparticles for Methanol Electro-Oxidation

Abstract

The low oxidation kinetics of alcohols and the need for expensive platinum group metals are still some of the main drawbacks for the commercialization of energy efficient direct alcohol fuel cells. In this work, we investigate the influence of nitrogen doping of ordered mesoporous carbon (CMK) as support on the electrochemical activity of PtRu nanoparticles. Nitrogen doping procedures involve the utilization of pyrrole as both nitrogen and carbon precursor by means of a templating method using mesoporous silica. This method allows obtaining carbon supports with up to 14 wt. % nitrogen, with an effective introduction of pyridinic, pyrrolic and quaternary nitrogen. PtRu nanoparticles were deposited by sodium formate reduction method. The presence of nitrogen mainly influences the Pt:Ru atomic ratio at the near surface, passing from 50:50 on the bare (un-doped) CMK to 70:30 for the N-doped CMK catalyst. The electroactivity towards the methanol oxidation reaction (MOR) was evaluated in acid and alkaline electrolytes. The presence of nitrogen in the support favors a faster oxidation of methanol due to the enrichment of Pt at the near surface together with an increase of the intrinsic activity of PtRu nanoparticles.

Electrocatalysis in Alkaline Media and Alkaline Membrane-Based Energy Technologies

“…Copyright 2019 American Chemical Society. Panel F is adapted with permission from ref . Copyright 2018 Multidisciplinary Digital Publishing Institute.…”

Electrochemical Behavior of Pt–Ru Catalysts Supported on Graphitized Ordered Mesoporous Carbons toward CO and Methanol Oxidation

“…Maiyalagan et al compared the activity of highly stable Pt-Ru nanoparticles supported on ordered mesoporous carbons and carbon blacks, finding higher current densities for the methanol oxidation on the OMC-supported materials [35]. Nitrogen doping of ordered mesoporous carbons has also been suggested as an alternative to improve the performance of Pt-Ru catalysts, generating methanol oxidation current densities higher than 6 mA cm −2 in acidic and alkaline media, which were attributed to both the presence of nitrogen as dopant and the increase in the porosity of the carbon supports as a consequence of the treatment employed to dope the ordered mesoporous carbons [36]. From the comparisons presented here, it is possible to suggest that the Pt and Pt-Ru catalysts supported on graphitized CMK-3 are suitable materials to be employed as anode catalysts in DMFCs.…”

Rhodium Nanoflowers on Three-Dimensional Graphitic Carbon Nitride Nanosheets/Graphene Hybrid Aerogels as Electrocatalysts for Methanol Oxidation

“…Nowadays, the gradual depletion of fossil fuels and severe environmental contamination problems promote great progress in developing clean energy sources and power transformation facilities. − Direct methanol fuel cells (DMFCs) have been considered as one of efficient energy generation devices in virtue of low pollutant emission, high power density, convenient refueling, wide working-temperature scope, and simple instrument packaging. , Notably, anode catalysts can effectively accelerate the kinetic rate of methanol electro-oxidation and therefore play essential roles in the determination of the DMFCs’ output power . As of now, platinum (Pt) and its derivative materials are commonly applied electrocatalysts, while their large-scale utilization is hindered because of their low abundance, high price, and susceptibility to anode poisoning, which turns down the hope of the successful commercialization of DMFCs. − Within this context, the exploitation of Pt-alternative species with excellent catalytic performance and affordable cost is of vital strategic importance for wide applications. − Previous reports have demonstrated that some non-Pt transition metal materials with d-band structures show methanol oxidation activity under certain circumstances. − Nonetheless, the current catalytic ability and use efficiency of Pt-free catalysts need further improvement on the road to their practical use. Among the range of Pt-free electrodes, it is interesting to find that rhodium (Rh) nanocrystals are perceived to feature comparable catalytic activity and much better CO poison resistance toward methanol electro-oxidation reaction under an alkali environment. , Thus, the exploration of Rh-based electrodes may rise to the challenge of enhanced performance for DMFCs.…”