Synthesis of highly active SnO_2-CNTs supported Pt-on-Au composite catalysts through site-selective electrodeposition for HCOOH electrooxidation

摘要

In this paper, site-selective electrodeposition method is developed to prepare Pt-on-Au composite catalysts for HCOOH electrooxidation. In the synthesis, Au nanoparticles are prepared through reduction of NaAuCl_4 by Sn(OH)_2 supported on carbon nanotubes and after thermal transformation of Sn(OH)_2 to SnO_2, composite supports (Au/SnO_2-CNTs) were obtained. By adjusting the potential of Au/SnO_2-CNTs coated glassy carbon electrode, Pt entities are selectively deposited on Au particles to form SnO_2-CNTs supported Pt-on-Au composite catalysts. The morphology and composition of the formed composite catalysts are characterized by instrument techniques such as X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). The site-selectivity of Pt electrodeposition on Au is confirmed by electrochemical measurements. The composite catalysts are tested to have high Pt mass activity toward HCOOH oxidation reaction, demonstrating that the synthesis method developed in this paper has promising potential for developing high performance composite catalysts. The Pt content effect on the catalytic activity is also tested for catalyst performance optimization.