N-Doped Porous Carbon from Sargassum spp. as Efficient Metal-Free Electrocatalysts for O2 Reduction in Alkaline Fuel Cells

Abstract

This work reports the synthesis of N-doped porous carbon (NPC) with a high surface area from Sargassum spp. as a low-cost alternative for electrocatalyst production for the oxygen reduction reaction (ORR). Sargassum spp. was activated with potassium hydroxide at different temperatures (700, 750, and 800 °C) and then doped with pyridine (N700, N750, and N800). As a result of the activation process, the 800 °C sample showed a high surface area (2765 m2 g−1) and good onset potential (0.870 V) and current density (4.87 mA cm−2). The ORR performance of the electrocatalysts in terms of their current density was N800 > N750 > N700 > 750 > 800 > 700, while the onset potential decreased in the following order: N800 > 800 > 750 > 700 > N700 > N750. The fuel cell performance of the membrane electrode assembly (MEA) prepared with electrocatalyst synthesized at 750 °C and doped with pyridine was 12.72 mW cm−2, which was close to that from Pt/C MEA on both the anode and cathode (14.42 mW cm−2). These results indicate that NPCs are an alternative to the problem of Sargassum spp. accumulation in the Caribbean due to their high efficiency as electrocatalysts for ORR.

Chitosan‐Derived N‐Doped Carbon for Light‐Mediated Carbon Dioxide Fixation into Epoxides

“…All the samples displayed characteristic D and G band in the corresponding Raman spectra, where D band represents defective sp 3 domain and G band represents ordered sp 2 domains. [46] It is observed that with increase in the calcination temperature from 300 to 500 °C, the I D /I G ratio of the N-doped carbon decreases from 1.03 to 0.69. However, further increase in the calcination temperature to 600 °C resulted in higher I D /I G ratio (0.87), indicating collapse of ordered structure at relatively higher temperature (Supporting info, Table S1).…”

A Review of a Decade of Local Projects, Studies and Initiatives of Atypical Influxes of Pelagic Sargassum on Mexican Caribbean Coasts

“…Sargassum can be used to obtain biocarbon and nanocarbon for the generation of electrocatalysts and specialized goods for high-tech industries. It has also shown great potential for the green synthesis of metal nanoparticles with multiple applications [85][86][87].…”

“…Sargassum aqueous extracts for electrocatalysts and the synthesis of platinum, gold and silver nanoparticles that can be used in the construction of electrochemical glucose sensing platforms, in the catalytic activity for blue methylene degradation and as antibacterials for Staphylococcus aureus and Pseudomonas aeruginosa) [85][86][87][101][102][103] Bioremediation and purification mechanisms Effectiveness of a Sargassum-based bioremediation system for the removal of metal ions and toxic dyes in water [104] 3.2.6. Regulations and Other Strategic Lines…”

Sargassum in Mexico: from environmental problem to valuable resource

“…Pelagic Sargassum chemical composition opens the opportunity to develop new nanostructured tailored materials for multiple applications, such as energy generation [142,143], medicine [144], antibacterial agents [145,146], and environmental remediation tools [147,148]. Recently, nanocarbons materials have been produced from brown sargassum for their use in electrochemical systems such fuel cells as [142] and supercapacitors [149], where the algae was activated at different temperatures presenting high specific surface areas <2500 m 2 /g. In the case of the alkaline fuel cell, the oxygen reduction reaction parameters of the nitrogen-doped carbon show comparable results with the traditional Pt electrocatalyst material [142].…”

“…Recently, nanocarbons materials have been produced from brown sargassum for their use in electrochemical systems such fuel cells as [142] and supercapacitors [149], where the algae was activated at different temperatures presenting high specific surface areas <2500 m 2 /g. In the case of the alkaline fuel cell, the oxygen reduction reaction parameters of the nitrogen-doped carbon show comparable results with the traditional Pt electrocatalyst material [142].…”