Cathodically activated Au/TiO2 nanocomposite synthesized by a new facile solvothermal method: An efficient electrocatalyst with Pt-like activity for hydrogen generation

We report here a facile, template-free and one-step solvothermal approach for the synthesis of high-temperature stable gold/titania nanocomposite (NCs), providing a new, simple, quick and inexpensive wet-chemical route. Our approach is based on the assembly of gold salt and titanium butoxide in dimethyl sulfoxide (DMSO). Also, we present here, for the first time, a cathodically activated Au/TiO2 catalyst with Pt/C activity for the hydrogen evolution reaction (HER) in 0.5 M H2SO4 in the dark. The as-prepared (unactivated) Au/TiO2 NCs exhibits considerable electrocatalytic activity for H2 generation in the dark, with a low onset potential (EHER) of −64 mV vs. RHE, a Tafel slope (-bc) of 60 mV dec−1 and an exchange current density (jo) of 0.12 mA cm−2. Long-term stability and durability tests in 0.5 M H2SO4, employing cyclic voltammetry technique (10,000 of repetitive cycling) and 72 h of chronoamperometry measurements at a high cathodic potential (cathodic activation), reveal that the electrocatalyst activates during such aging processes yielding an activated Au/TiO2 catalyst with Pt/C-like activity for H2 generation (EHER -3 mV, -bc: 35 mV dec−1, and jo: 0.95 mA cm−2). The outstanding HER activity of the activated catalyst is discussed.