PtRuFe/Carbon Nanotube Composites as Bifunctional Catalysts for Efficient Methanol Oxidation and Oxygen Reduction

Abstract

The design of bifunctional catalysts with high performance and low platinum for the oxygen reduction reaction (ORR) and the methanol oxidation reaction (MOR) is of significant implication to promote the industrialization of fuel cells. In our work, Pt/carbon nanotube (CNT), Pt3Ru/CNT, and PtRu/CNT catalysts were synthesized by plasma heat treatment, in which the pyrolysis reduction of organometallic salts and the dispersion of CNTs were achieved simultaneously, and catalytic nanoparticles with uniform particle size were anchored on the dispersed CNT surface. Later, Fe was further introduced, and PtFe/CNT, Pt3RuFe/CNT, and PtRuFe/CNT catalysts were synthesized by calcination, and the structure and electrochemical properties in both MOR and ORR of all as-synthesized catalysts were investigated. The results indicated that plasma thermal treatment has the advantage of rapidness and immediacy in the synthesis of catalysts, and the Pt/CNT, Pt3Ru/CNT, and PtRu/CNT catalysts exhibited better electrocatalytic properties than commercial platinum (JM-Pt/C) catalysts. Meanwhile, the introduction of Fe during the calcination further changed the surface electronic properties of catalytic nanoparticles and enhanced the graphitization degree of catalysts; the PtRuFe/CNT catalyst exhibited outstanding electrocatalytic properties with a mass activity of 834.3 mA mg–1 for MOR and a half-wave potential of 0.928 V in alkaline media for ORR. The combination of plasma thermal treatment and calcination puts forward a novel strategy for the optimization of catalysts, and the synthesis method based on plasma dispersion needs to be further optimized to achieve its large-scale promotion.

Electronic Structure Effect of PtCo Alloy with Adjustable Compositions for Efficient Methanol Electrooxidation

“…Currently, platinum-based alloys are well recognized as high-performance electrocatalysts for accelerating the sluggish MOR process. − However, the limited storage capacity and exorbitant cost of platinum continue to impede the widespread adoption of fuel cells. Moreover, Pt-based MOR catalysts encounter obstacles such as poor utilization efficiency, limited durability, and the harmful effects of surface intermediates like CO. − Consequently, the pivotal challenge in catalyst development for fuel cells lies in enhancing the utilization and effectiveness of Pt. − …”

Catalyst Development for High‐Temperature Polymer Electrolyte Membrane Fuel Cell (HT‐PEMFC) Applications

“…Often this yields in welcomed increase in mass activity and CO-poisoning inhibition. [152,153] Wang et al demonstrated a core-shell structured PtFe@PtRuFe nanocatalyst, with an ordered PtFe intermetallic core and a 3-5 atomic-layers-thick PtRuFe shell. [153] The well-defined nanostructure exhibited excellent stability to CO poisoning and resistance to Fe leaching, achieving a factor of 1.68 time enhancement in MOR mass activity compared to the state-of-the-art PtRu catalysts (0.41 mA μg Pt −1 at 0.75 V vs RHE).…”

“…Often this yields in welcomed increase in mass activity and CO‐poisoning inhibition. [ 152,153 ] Wang et al. demonstrated a core‐shell structured PtFe@PtRuFe nanocatalyst, with an ordered PtFe intermetallic core and a 3–5 atomic‐layers‐thick PtRuFe shell.…”

Nitrogen-doped carbon nanotubes embedded with nitrogen-doped carbon black anchoring Pd nanocrystals to boost ethanol electrooxidation

“…16 Nevertheless, the performances of CNTs as substrates are still far below expectations on account of the lack of active sites for anchoring noble metals and their proneness to agglomerate caused by the large aspect ratio, van der Waals forces and electrostatic interactions. 17 Heteroatom doping such as nitrogen-doping is an influential strategy to fine-tune the electrical characteristics and chemical reactivity of CNTs. 18 Considering the fact that the nitrogen atom has comparable atomic size and contains five valence electrons available to form strong valence bonds with carbon atoms, nitrogen doping is a promising strategy to bring adequate nitrogen-containing functional groups into CNTs as active sites for anchoring noble metals.…”