Pt electrocatalyst supported on metal ion-templated hierarchical porous nitrogen-doped carbon from chitosan for methanol electrooxidation

Abstract

Hierarchical porous nitrogen-doped carbon (HPNC) derived from chitosan is synthesized through a novel metal ion-templated strategy. In this process, the absorbed Cu(II)-loaded chitosan was calcined at various temperatures which results in carbon/Cu composites. After removal of Cu particles with acid medium, hierarchical porous carbon forms which includes macropores, mesopores and micropores. The specific surface area of HPNC900 reaches 755 m2 g−1. The XPS results show that all the carbon materials contain nitrogen as the doped element due to the use of chitosan as a nitrogen-containing carbon source. Furthermore, highly dispersed Pt nanoparticles have been successfully deposited on the as-prepared HPNC through the in-situ reduction method. The average size of Pt nanoparticles anchored on HPNC900 is only 2.76 ± 0.33 nm. The synthesized products are characterized by TEM, SEM and XRD analysis techniques. Among the studied electrocatalysts, the as-prepared Pt/HPNC900 electrocatalyst (HPNC fabricated at 900 °C) shows superior electrocatalytic activity and stability towards methanol oxidation in comparison with Pt/Vulcan XC-72 catalyst. The current density of methanol oxidation on Pt/HPNC900 is ∼2.5 times higher than that of Pt/Vulcan XC-72 catalyst. The enhanced electrocatalytic activity is ascribed to hierarchical porous structures, nitrogen-doped surface characteristic and high BET specific surface area of HPNC. Therefore, the present method is very useful for fabrication of high-performance electrocatalyst for methanol oxidation.