De-Alloying Synthesis of Mesoporous Pt-Ti-Ce Hydrogen Evolution Nanocatalysts with Exposed High-Index Crystal Planes

Developing efficient hydrogen evolution electrodes for sustainable energy conversion applications has been a research hot spot in recent years. Herein, a carbon-supported Pt-Ti-Ce nanocatalyst is synthesized by ion beam sputtering and ultrasonic-assisted electrochemical de-alloying treatment. The results of x-ray diffraction, transmission electron microscopy, x-ray photoelectron spectroscopy, cyclic voltammetry, and linear sweep voltammetry results illustrate the behavior of Pt alloying and de-alloying on the phase structure of the catalysts, their surface morphology, exposed crystal surface, active component distribution, hydrogen evolution activity, and stability. The diameters of about 80% of the pores of the mesoporous carbon-supported Pt-Ti-Ce nanocatalyst are smaller than or equal to 20 nm, thereby, resulting in an increase in the geometric specific surface area by 300%. In addition, the catalyst surface exposed the high-index planes (022), (231), and (004) of Pt₅Ti₃ with a 4-7% shrinkage in interplanar spacing. Compared with commercial Pt/C catalysts, the Pt content reduced to 97%, the electroactive specific surface area increased by more than 101%, and the hydrogen evolution activity and stability increased to 86.3 and 161.1%, respectively. The proposed strategy offers a short synthesis time, regulates the exposure of high-index crystal faces, and achieves strong catalytic activity and increased stability for Pt-Ti-Ce alloy nanocatalysts.