Title : Hydrogen spillover enhances alkaline hydrogen electrocatalysis on interface-rich metallic Pt-supported MoO3
Abstract:
The sluggish hydrogen evolution / oxidation reaction (HER/HOR) kinetics in base is the key issue for commercializing alkaline fuel cells and electrolyzers. It’s also quite challenging to decrease the noble metal loading without sacrificing performance. In this talk, I will discuss synthesis and the hydrogen spillover induced improved HER/HOR activity of platinum nanostructures supported metal oxide such as MoO3 in base. The catalyst exhibited 66.8 mV overpotential to reach 10 mA/cm2 current density with 41.2 mV/dec Tafel slope for HER. For HOR, the catalyst possesses mass-specific exchange current density of 505.7 mA/mgPt, which is far better than Pt/C. The hydrogen binding energy is key descriptor for the HER/HOR. We found H-spillover from Pt to MoO3 enhances the Volmer/Heyrovsky process, which enhances HER/HOR performance. The work function value of Pt [Φ = 5.39 eV) is less than that of β-MoO3 (011) [Φ = 7.09 eV], which revealed charge transfer from Pt to β-MoO3, suggests the feasibility of H-spillover. We propose that the H2O or H2 dissociation takes place on Pt and interfaces to form Pt–Had or (Pt/MoO3)–Had, and some of the Had shifted to MoO3 sites through hydrogen spillover. Then, Had at the Pt and interface, and MoO3 sites reacted with H2O and HO− to form H2 or H2O molecules, thereby boosting the HER/HOR activity. In this talk, I will discuss development of of hydrogen-spillover-based electrocatalysts for use in renewable energy devices.
