Nitrogen-Doped Graphene Aerogel Microspheres Used as Electrocatalyst Supports for Methanol Oxidation

Abstract

Nitrogen-doped graphene aerogel microspheres (rGNAMs) are prepared by electrospraying the graphene oxide dispersion with pyrrole and an oxidation agent and then subjecting it to freeze-drying and thermal annealing. The rGNAMs possess a high surface area, an interconnected pore structure, and uniform N doping. The Pt nanoparticles (Pt NPs) are loaded into rGNAMs through a hydrothermal reduction reaction to obtain the Pt/rGNAM composite catalyst for methanol electrooxidation. The N-doping structure of rGNAMs can improve the loading ratio of Pt on the carrier, decrease the dimension of Pt NPs, homogenize the dispersion of Pt NPs, and increase the content of Pt(111) crystal planes. Consequently, the oxidation activity of Pt/rGNAMs to methanol is improved compared to that without N doping. The optimized Pt/rGNAM composites used as anode electrocatalysts display a remarkable mass activity of 840.11 mA mg–1 for methanol electrooxidation, which is about 4.9, 2.9, and 2.7 times higher than that of Pt/C, Pt/rGNAB (Pt/N-doped graphene aerogel bulk), and Pt/rGNAS (Pt/N-doped graphene aerogel millimeter spheres), respectively. Moreover, the Pt/rGNAMs also show superior long-term electrocatalytic stability. This work develops a new Pt/rGNAMs composite for potential application in fuel cells.

Confining ultrafine Pt nanoparticles on In2O3nanotubes for enhanced selective methanol production by CO2hydrogenation

“…Typically, for Pt@In 2 O 3 , the peaks with binding energies of 70.23 and 73.48 eV are attributed to Pt 4f 7/2 and Pt 4f 5/2 of Pt 0 , while those at 70.73 and 73.88 eV are assigned to Pt 4f 7/2 and Pt 4f 5/2 of Pt 2+ , respectively. 33–36 Comparatively, both metallic Pt and Pt 2+ species are also detected in Pt/In 2 O 3 , but the binding energies of the characteristic peaks of Pt species in Pt@In 2 O 3 are smaller than those in Pt/In 2 O 3 . This finding can be understood as the Pt species replacing the In 3+ ions in the In 2 O 3 lattice or locating at the defective sites.…”

Carbon black‐heteroatom‐doped graphene aerogel hybrid supported platinum nanoparticles as electrocatalysts for oxidation of methanol and formic acid

“…In a study, the ECSA of the Pt nanoparticles on N‐doped graphene support is approximately 78% higher than that of the Pt nanoparticles on graphene support, which is attributed to the superior dispersion of the Pt nanoparticles on N‐doped support 42 . In another study, NGA microspheres with different N doping amounts supported catalysts for MOR showed higher ECSA due to the better loading and anchoring of Pt, but lower ECSA is observed due to the obvious agglomerations 43 …”

Ultrahigh Mass Activity Pt Entities Consisting of Pt Single atoms, Clusters, and Nanoparticles for Improved Hydrogen Evolution Reaction

“…Mesoporous carbons are attractive as catalyst supports because of their large surface area, high conductivity, controlled mesoporous structure, and excellent stability in both acid and basic solutions. [29,30] Furthermore, N-doping of mesoporous carbons can increase Pt dispersion by enabling strong Pt-N interactions between the N-functionalities of N-doped carbons and either Pt precursors [31] or Pt NPs, [32][33][34] (or Pt clusters and single sites) where the strong Pt-N interactions can also stabilize Pt and inhibit Pt entity detachment. [31] In this work, we synthesized highly dispersed Pt entities supported on mesoporous N-doped carbon (MPNC) nanospheres for improved HER.…”