Surface Assembling of Highly Interconnected and Vertically Aligned Porous Nanosheets of Gd−CoB on TiO2 Nanoflowers for Durable Methanol oxidation Reaction

Abstract

AbstractBeing a green and carbon‐neutral technology, direct methanol fuel cell (DMFC) has attracted much attention while endowing highest mass energy density at low operating temperature. However, the multistep and multielectron process of methanol oxidation reaction (MOR) taking place at the anodic side in DMFC is an energy intense process. In addition, the in situ generated CO can severely deteriorate the catalytic efficiency of electrode material, which can be, however, realized to develop a competent catalytic module. Here, we present a first report on a highly interconnected and facile growth of vertically aligned Gd doped CoB assembled on the surface of rationally developed TiO2 nanoflower (NFs) for MOR. Initially, we developed the TiO2 NFs as support followed by cathodic deposition of Gd−CoO to create an electronic contact with underlying support. After then, finally treated with NaBH4 to further modify the surface of overall hybrid material, characterized with various techniques (UPS, XPS, XRD, SEM, TEM, Raman, and BET analyzer). During electrocatalysis, Gd−CoB@TiO2 was found highly efficient with inherently low charge transfer resistance (Rct) and ability to generate highest current density (400 mA/cm2) with negligible loss in activity even after long term stability (20 h) while using highly concentrated methanol. Meanwhile, the surface modification with B, extended and highly interconnected nature of amorphous and promisingly mesoporous nanosheets in 3D manner further ameliorate the available surface for catalysis. In comparison with analogues samples and literature, it is anticipated that Gd could modify the electronic structure of overall hybrid in such way to energize the redox couple of Co+2/+3 in Gd−CoB against the CO poisoning effect. Further, the XPS and Raman analysis before and after catalysis also indicates that in‐situ generated oxide/hydroxide formation with high inherent polarizability weaken the C−O−H bond of methanol and thus facilitate the dynamic release of involved intermediates.