Nanocomposite Cathode Catalysts Containing Platinum Deposited on Carbon Nanotubes Modified by O, N, and P Atoms

Vera Bogdanovskaya,Inna Vernigor,Marina Radina,Oleg Korchagin,Vladimir Andreev

doi:10.3390/catal11030335

Vera Bogdanovskaya, Inna Vernigor + Show 3 more

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https://doi.org/10.3390/catal11030335

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Abstract

Platinum deposited on dispersed materials has so far been the most demanded catalyst for creating cathodes for a wide range of electrochemical power sources. This paper sets out to investigate the effect of carbon nanotube (CNT) modification by O, N, and P atoms on the structural, electrocatalytic, and corrosion properties of the as-synthesized monoplatinum catalysts. The investigated Pt/CNTmod catalysts showed an increased electrochemically active platinum surface area and electrical conductivity, as well as an increased catalytic activity in the oxygen reduction reaction (ORR) in alkaline electrolytes. The improved characteristics of Pt/CNT catalysts are explained by alterations in the composition and number of groups, which are formed on the CNT surface, and their electronic structure. By the sum of the main characteristics, Pt/CNTHNO3+N and Pt/CNTHNO3+NP are the most promising catalysts for use as cathode materials in alkaline media.

Highlights

Oxygen electroreduction is one of the most important reactions due to its wide application and demand for practical use in fuel cells (FC) and metal-air power sources [1].The process of cathodic oxygen reduction limits the characteristics of fuel cells, since the reaction proceeds with a significant overvoltage reaching 300 mV relative to the equilibrium oxygen potential of the O2 /H2 O system
Specific surface area for nitrogen-modified carbon nanotube (CNT) and reaches 100% in the case of a catalyst synthesized on phosphorus-doped CNTs
The largest BET surface area corresponds to the Pt/CNTHNO3+N catalyst

Summary

Introduction

The process of cathodic oxygen reduction limits the characteristics of fuel cells, since the reaction proceeds with a significant overvoltage reaching 300 mV relative to the equilibrium oxygen potential of the O2 /H2 O system In this regard, it is necessary to create catalytic systems that would meet the requirements of both high activity and selectivity (oxygen reduction directly to water), and stability in harsh operating conditions (oxygen atmosphere, elevated temperatures, and solution pH). Platinum deposited on a dispersed carbon support (Pt/C) is widely used as a catalytic material for the oxygen reduction reaction (ORR) [2] Such systems provide high activity; despite the excellent corrosion resistance of metallic platinum, Pt/C catalysts degrade during long-term tests in FC due to exposure to corrosive environments [2,3].

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