The rapidly increasing energy demand for human activities stimulates the lasting research interests to develop renewable energy alternatives worldwide. Fuel cell, as a clean and efficient energy conversion device, is one of promising techniques in tackling future global energy crisis. The big challenges for the practical application of this technique are to minimize the use and maximize the catalytic activity of scarce, expensive but still best platinum-based catalysts, and tackle the issue of the sluggish cathode oxygen reduction reaction (ORR).^1,2

In this presentation, several reasonable ways for designing new nanocatalysts with high electrocatalytic activities for ORR will be discussed. For example, 1) By improving the structures of Pt-based catalysts and harnessing the synergetic catalytic effect from support, a series of nanocatalysts with efficient usage of Pt component and enhanced electrocatalytic performance were developed, including Pt nanocrystal assembled hollow Pt nanostructures hanged onto graphene layer,³ well-dispersed Pt nanocrystals on Mn₃O₄ coated CNTs prepared via an in-situ self-deposition process,⁴ and CNx/CNTs embedded with Pt nanocrystals for improving stability, ⁵ etc. 2) For further minimizing the catalyst cost, a variety of non-PGM (platinum group metal) catalysts with comparable/superior electrochemical performance and durability were developed, such as in-situ nitrogen-doped nanoporous carbon nanocables,⁶ improved graphene/carbon nanotube composites,⁷ and selectively-nitrogen-doped graphene via space confinement etc.⁸ 3) The further improvement of the performance can be achieved by introducing transition metal or nanostructures into these nanocatalysts.^9,10 A simple, reproducible and cost-effective protocol to produce a nanocomposite from graphene supported layered double hydroxide will be also discussed, which will be interesting for cost-effective mass production of electrocatalysts for industrial applications.¹¹