Pt₁(CeO₂)_0.5 Nanoparticles Supported on Multiwalled Carbon Nanotubes for Methanol Electro-oxidation

Abstract

Deep eutectic solvents (DESs), regarded as an analogue of ionic liquids, consist of Brønsted or Lewis acids mixed with certain bases. These solvents are ideal around room temperature and possess a considerably low melting point relative to the involved single components. The important features of DESs including conductivity, high viscosity, biodegradability, and surface tension make them promising green sustainable media for the synthesis of various nanomaterials, which have been used in the field of energy and environment in the recent 5 years. Herein, synthesis of ultrafine Pt1(CeO2)0.5-decorated multiwalled carbon nanotube nanoelectrocatalysts (Pt1(CeO2)0.5/MWCNTs-D) was performed using the DESs. We found that DESs play a vital role in the synthesis of uniform dispersion and ultrafine nanoparticles to strengthen the interaction of CeO2 and Pt, as well as the controllable synthesis of CeO2. Furthermore, the addition of CeO2 not only slightly promotes Pt(II) content but also can obviously enhance the electrochemical performance of Pt1(CeO2)0.5/MWCNTs-D. The catalyst exhibits better CO antipoisoning capability and greater catalytic performance (onset potential: 0.44 V and peak current: 641.6 mA mgPt–1) toward methanol oxidation than that of Pt/MWCNTs-W synthesized in water (0.58 V and 229.9 mA mgPt–1) and Pt/MWCNTs-D synthesized in DESs (0.55 V and 459.2 mA mgPt–1). The main features of Pt1(CeO2)0.5/MWCNTs-D such as higher peak current, lower oxidation potential, CO antipoisoning capability, and larger electrochemical active surface area toward oxidation of methanol can benefit the construction of highly electroactive Pt-based nanomaterials for the direct methanol fuel cell applications.