Pt nanoparticles supported on different carbon forms for hydrogen production from ammonia electrocatalysis

This study explores the influence of different carbon supports for Pt nanoparticles (NPs) synthesized via one-pot glycerol-assisted polyol method. The precursor, K₂PtCl₄, is dissolved in glycerol as the reaction medium, enabling the formation of Pt NPs supported on multi-walled carbon nanotubes (CNTs) and graphene nanosheets powder (GNS) with both high and low Pt loadings at moderate temperature. Pt NPs supported on CNTs and GNS are systematically characterized by XRD, STEM-EDS, XPS, ICP-AES, spectrophotometry, and cyclic voltammetry to examine crystallite size, morphology, electronic structure, composition, ammonia quantification, and electrochemical properties, respectively. TEM results reveal that Pt NPs are uniformly distributed on both CNTs and GNS, further supported by STEM-EDS analysis, which detects Pt signals exclusively on the carbon supports. Pt electronic structure is more significantly modified by GNS than other carbon supports, referring to the downshift of Pt d-band center. Pt NPs are utilized for ammonia electrocatalysis, demonstrating exceptional electrocatalytic activity compared to commercial Pt/C. Stability is evaluated using chronoamperometry over 12h period for the representative sample from each support, both of which surpass the performance of Pt/C. After 12h stability test, ammonia consumption measured by spectrophotometry is found to be higher in Pt/GNS-high than Pt/CNT-high and Pt/C.