Confined tuning of the charge distribution of Pt electrocatalyst for reinforcing anti-poisoning ability: Toward efficient separation of hydrogen from gases containing ammonia

Abstract

The development of catalysts for hydrogen oxidation reaction (HOR) with enhanced resistance to ammonia poisoning is an important factor in the practical application of hydrogen electrochemical purification devices (HEPDs). This paper reports on the creation of a highly active and anti-ammonia HOR catalyst developed by tuning the charge distribution of the support material through nitrogen-doping of carbon. The nitrogen-doped carbon-supported platinum catalyst (Pt-N2/KB, 2.03 wt% Pt) achieves a high mass activity and exchange current density of 2788 mA mgpt-1 and 1020 mA mgpt-1, respectively, which are 5.4 and 4.7 times higher than that of the comm. 20% Pt/C. The Pt-N2/KB catalyst also displays a lower percentage of current decay and enhanced electrochemical stability, indicating superior anti-ammonia toxicity in the tests with HEPD. Density functional theory (DFT) calculations reveal that the hydrogen adsorption free energy (ΔGH*) on the surface of Pt-N2/KB is close to zero and has a lower ammonia adsorption energy, thus accounting for its superior HOR activity and anti- ammonia poisoning ability. Consequently, this work facilitates the implementation of HOR catalysts for anti-ammonia poisoning in the HEPDs, thus accelerating the advancement of ammonia cracking for hydrogen production.