IrO2 and Pt Doped Mesoporous SnO2 Nanospheres as Efficient Electrocatalysts for the Facile OER and HER

Abstract

Electrocatalytic hydrogen and oxygen evolutions via water splitting are very demanding in the context of renewable energy and sustainable environment. We first report the synthesis of wormhole-like mesoporous tin oxide (MTO-S) by using sodium lauroyl sarcosinate as structure directing agent under hydrothermal reaction conditions followed by calcination and loading with IrO2 or Pt nanoparticles at its surface by simple wet-chemical methods. These IrO2 and Pt-loaded SnO2 nanomaterials are thoroughly characterized by small and wide-angle powder XRD, nitrogen adsorption/desorption analysis, FTIR, XPS spectroscopy, UHR-TEM, FE-SEM, TG/DTA and NH3-TPD analysis. The electrochemical water splitting measurements of the IrO2 and Pt doped mesoporous SnO2 nanostructured materials suggested fine dispersion of these metal/metal oxide nanoparticles at the mesopore surface and facile electron hopping could enhance the rate of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activity of IrO2@MTO-S and Pt@MTO-S nanocomposites, respectively. As a result, the IrO2@MTO-S modified electrode exhibits unprecedented OER activity with a very low overpotential of 240mV at 10mAcm(-2), which is lower than the state-of-the-art catalyst IrO2/C (360mV) and other reported catalysis. Pt@MTO-S also exhibit excellent HER activity with an ultralow overpotential of 73mV at 10mAcm(-2). These findings may uncover new opportunities for IrO2@MTO-S and Pt@MTO-S as OER and HER electrocatalysts for future water electrolysis.