This review presents a summary of recent progress and strategies in fabricating MOF-based nanostructures for electrochemical applications.

Replacing the rare and precious platinum (Pt) electrocatalysts with earth-abundant materials for promoting the oxygen reduction reaction (ORR) at the cathode of fuel cells is of great interest in developing high-performance sustainable energy devices. However, the challenging issues associated with non-Pt materials are still their low intrinsic catalytic activity, limited active sites, and the poor mass transport properties. Recent advances in material sciences and nanotechnology enable rational design of new earth-abundant materials with optimized composition and fine nanostructure, providing new opportunities for enhancing ORR performance at the molecular level. This Review highlights recent breakthroughs in engineering nanocatalysts based on the earth-abundant materials for boosting ORR.

Rational design of non-noble metal catalysts with the electrocatalytic activity comparable or even superior to Pt is extremely important for the future fuel cell-based renewable energy device. Herein, we demonstrate a new concept that metal-organic framework (MOF) can be used as a novel precursor to insitu encapsulate Co@Co 3 O 4 @C core@bishell nanoparticles (NPs) into a highly ordered porous carbon 10 matrix (CM) (denoted as Co@Co 3 O 4 @C-CM). The central cobalt ions from MOF are used as metal source to produce Co metal cores, which are later transformed into fancy Co@Co 3 O 4 nanostructure via a controlled oxidation. The most notable feature of our Co@Co 3 O 4 @C-CM is that the highly ordered CM can provide much better transport pathway than the disordered pure MOF derived nanostructure that can facilitate the mass transport of O 2 and electrolyte. As a result, the well-designed Co@Co 3 O 4 @C-CM 15 derived from MOF shows almost identical activity but superior stability and methanol tolerance for ORR relatively to the commercial Pt/C in alkaline medium. Our work first reports the novel Co@Co 3 O 4 @C nanostructure from MOF and also reveals the important role of the introduction of highly ordered carbon matrix into MOF derived catalyst on enhancing the ORR activity and stability. To the best of our knowledge, Co@Co 3 O 4 @C-CM is the most efficient non-noble metal nanocatalyst ever reported for 20 ORR. 65 (denoted as Co@Co 3 O 4 @C-CM), which is very different from the preparation of traditional nanocatalysts directly derived from MOFs. The central cobalt ions from MOFs were used as metal source to produce Co metal cores, which were later transformed into Co@Co 3 O 4 NPs via a simple oxidation process. Co 3 O 4 has 70