Abstract:

In the last two decades, fuel cells captured worldwide attention as a promising renewable emission-free technology to meet the increasing demand of clean energy for stationary and transportation applications. Currently, platinum (Pt) is the most widely used electrocatalyst for both hydrogen oxidation reaction (HOR) at anode and oxygen reduction reaction (ORR) at cathode. However, the high-cost and scarcity of Pt have become the major challenges for commercialization of fuel cells. To overcome the above mentioned problems, great progress has been made in developing more active electrocatalysts on the basis of Pt-based and Pt-free electro catalysts. For the Pt-based electrocatalysts, composition, morphology, surfaces tructure, synthesis method, and post-treatment play significant roles in determining their activity and stability. In general, theactivity of Pt-based electrocatalysts can be enhanced by alloying Pt with other transition metals, forming a core-shell structure to improve the utilization of Pt atoms, forming and maintaining structures with only the highest active facets exposed to electrolytes, and creating a porous structure toincrease the surface area and strain. For the Pt-free electrocatalysts, a great progress has been made in the last decade, including heteroatom-containing carbon, transition metal oxides and transition metal macrocyclic compounds. The best performing non-precious catalysts even exceed those Pt-based catalysts in alkaline electrolytes. Generally, their ORR activity is less competitive in acidic media. To review the achievements that have been madein China and push forward the further development of electrocatalyst and electrocatalysis in fuel cells, some leading scientists were invited to contribute their recent advances and prospects in this field. I wish to take this opportunity to thank all the authors, reviewers, and editorial staffs of Journal of Electrochemistry for their professional contributions to this special issue.