Pt-Ni Trimetallic Nanoparticles Anchored on Graphene Oxide: an Effective Catalyst for Ammonia-Borane Hydrolysis and Direct Electrooxidation of Ammonia-Borane in Alkaline Solution

Abstract

In this study, graphene oxide supported platin, nickel and cobalt trimetallic nanoparticles (PtNiCo@GO) were prepared by the impregnation/reduction method. The catalytic performances of PtNiCo@GO catalysts prepared with different atomic ratios were investigated for hydrogen production and electro-oxidation of ammonia-borane (AB). For hydrolysis of ammonia-borane, Pt0.8Ni0.1Co0.1@GO catalyst exhibited higher catalytic activity than Pt0.6Ni0.2Co0.2@GO, Pt0.4Ni0.3Co0.3@GO, and Pt0.2Ni0.4Co0.4@GO. The hydrogen generation rate and turnover frequency values were found to be 540 mL min- 1g- 1 and 42.8 min- 1 , respectively, in the experiment conducted at 35 degrees C, 0.5 mmol AB, and 50 mg Pt0.8Ni0.1Co0.1@GO catalyst. The activation parameters (Ea, Delta H # , and Delta S # ) in the catalytic hydrolysis of AB were obtained at 42.22 kJ/mol, 31.95 kJ/mol and-114.82 J/(mol x K), respectively. The effects of the PtNiCo@GO catalyst on AB electro-oxidation were made at a scanning rate of 100 mV/s in the potential range of- 1V/+1V against Ag/AgCl, and chronoamperometry measurements were made at constant potentials of- 0.2V, 0.1V and 0.4V. For cyclic voltammetry and chronoamperometry measurements, 5 mM [Fe(CN)6]3/4 (1 M KCl) redox probe and 1 M NaOH + 50 mM AB solution were used.