Interface-Controlled Synthesis of Platinum-Free Anode Catalyst for Fuel Cells Application

Abstract

The ever-growing concerns about global warming and energy security demand the expansion of renewable energy sources as viable alternatives to fossil-fuel-based technologies. In all of these concepts, hydrogen is the key energy carrier and, despite several hurdles that still need to be overcome. Two reactions that will inevitably reign over the hydrogen economy are the HOR and its reverse, the HER. The HOR predominantly finds application in fuel cells, while the HER features in various electrolysers. However, the sluggish kinetics of HER and HOR in a basic environment causes high overpotential and associated large energy consumption, which greatly hinders practical application of alkaline electrolysis and alkaline fuel cell. As a typical example, though platinum (Pt) is generally believed as one of the best electrocatalysts for HER and HOR, its catalytic activity is about two orders of magnitude lower in alkaline environment compared with that in acidic electrolyte. Therefore, it is extremely crucial to synthesize a new HOR catalyst with low cost and high activity for HOR in alkaline environment to replace Pt in FCs. The key to develop a highly active Pt-free HOR catalysts in alkaline environment is constructing a catalytic interface with suitable hydrogen (H) and hydroxyl (OH) binding energies (HBE). Such interface can promote the desorption of Had intermediate and depress adsorption of hydroxyl species. Herein, we report a synthetic method of Ru NPs with strong oxidation resistance and high activity for HOR in alkaline media, by using TiO2 to construct an interface with controlled H and OH binding energy. Our results show that the low-cost RuTiO2/C catalyst exihits an excellent HOR catalytic activity for HOR which is much better than that of Pt based catalysts. This opens a new way to tuning the catalyst interface for the preparation of high performance HEMFC anode catalysts. Figure 1