Unique sandwich structure of Ru@TiO2: salicylic acid micro-etching from K2Ti2O5 and high-performance electrocatalytic hydrogen evolution

Abstract

An Ru@TiO₂ sandwich structure of TiO₂|Ru|TiO₂ is developed via a novel synthesis method by etching two-dimensional K₂Ti₂O₅ in a salicylic acid solution and further inserting Ru nanodots between anatase TiO₂ layers. In this sandwich structure, Ru nanodots are in close contact with anatase TiO₂ layers and dispersed more on the edge, which promotes electron transfer and limits the aggregation of Ru nanoparticles. The orientation distribution of the Ru@TiO₂ sandwich obtained with processing electron diffraction (PED) indicates that {002} crystal planes are dominant for Ru nanodots, which exhibit high HER activity. Applied to the hydrogen evolution reaction (HER), a 2.54 wt% Ru@TiO₂ sandwich not only shows comparable activity to 20 wt% Pt/C but also exhibits higher current densities at low potentials. Meanwhile, the mass and price activities of Ru@TiO₂ sandwich are 13 and 50 times, respectively, higher than those of 20 wt% Pt/C. This report provides a novel approach to designing the morphology of hetero-structured catalysts.