Reversed Charge Transfer and Enhanced Hydrogen Spillover in Platinum Nanoclusters Anchored on Titanium Oxide with Rich Oxygen Vacancies Boost Hydrogen Evolution Reaction

Abstract

The catalytic activity of metal clusters is closely related with the support; however, knowledge on the influence of the support on the catalytic activity is scarce. We demonstrate that Pt nanoclusters (NCs) anchored on porous TiO₂ nanosheets with rich oxygen vacancies (V_O -rich Pt/TiO₂ ) and deficient oxygen vacancies (V_O -deficient Pt/TiO₂ ), display significantly different catalytic activity for the hydrogen evolution reaction (HER), in which V_O -rich Pt/TiO₂ shows a mass activity of 45.28 A mg_Pt ^-1 at -0.1 V vs. RHE, which is 16.7 and 58.8 times higher than those of V_O -deficient Pt/TiO₂ and commercial Pt/C, respectively. DFT calculations and in situ Raman spectra suggest that porous TiO₂ with rich oxygen vacancies can simultaneously achieve reversed charge transfer (electrons transfer from TiO₂ to Pt NCs) and enhanced hydrogen spillover from Pt NCs to the TiO₂ support, which leads to electron-rich Pt NCs being amenable to proton reduction of absorbed H*, as well as the acceleration of hydrogen desorption at Pt catalytic sites-both promoting the HER. Our work provides a new strategy for rational design of highly efficient HER catalysts.

Keywords: charge transfer reversion; electrocatalysis; hydrogen spillover effect; platinum nanoclusters.