Ultralow-loading platinum-cobalt fuel cell catalysts derived from imidazolate frameworks

Abstract

Achieving high catalytic performance with the lowest possible amount of platinum is critical for fuel cell cost reduction. Here we describe a method of preparing highly active yet stable electrocatalysts containing ultralow-loading platinum content by using cobalt or bimetallic cobalt and zinc zeolitic imidazolate frameworks as precursors. Synergistic catalysis between strained platinum-cobalt core-shell nanoparticles over a platinum-group metal (PGM)–free catalytic substrate led to excellent fuel cell performance under 1 atmosphere of O2 or air at both high-voltage and high-current domains. Two catalysts achieved oxygen reduction reaction (ORR) mass activities of 1.08 amperes per milligram of platinum (A mgPt−1) and 1.77 A mgPt−1 and retained 64% and 15% of initial values after 30,000 voltage cycles in a fuel cell. Computational modeling reveals that the interaction between platinum-cobalt nanoparticles and PGM-free sites improves ORR activity and durability.

Zinc‐Mediated Template Synthesis of Fe‐N‐C Electrocatalysts with Densely Accessible Fe‐Nx Active Sites for Efficient Oxygen Reduction

“…Among the various Pt‐group‐metal‐free (PGM‐free) catalysts, single iron atoms dispersed on nitrogen‐doped carbon (Fe‐N‐C) electrocatalysts are the most promising candidates to replace Pt‐based ORR catalysts . The single atomic (SA) iron coordinated nitrogen (Fe‐N x ) moieties in the carbon matrix are commonly recognized as active centers for catalyzing sluggish ORR kinetics . Currently reported strategies for synthesizing Fe‐N‐C electrocatalysts unavoidably involve high‐temperature pyrolysis of Fe‐ and N‐containing precursors .…”

Rational Design of Spinel Cobalt Vanadate Oxide Co2VO4 for Superior Electrocatalysis

“…The design of efficient and stable materials for electrochemical energy devices, such as electrolyzers, fuel cells and metal–air batteries is of intense academic and industrial interest. Research effort has focused on exploring cost‐effective and earth‐abundant transition metals, e.g., Mn, Fe, Co and Ni, oxides as alternatives to expensive noble metals for large‐scale application in these renewable energy technologies .…”

Metal–Organic Frameworks Based Electrocatalysts for the Oxygen Reduction Reaction

“…Other than highly active sites, the density and utilization rate of active sites, charge transfer, interface properties between different components, electrocatalysts and electrolyte, etc., are all important factors for improving the overall electrocatalytic performance Highly efficient and stable electrocatalysts in acidic media can be realized by incorporation of M‐N‐C moieties or Pt‐based alloys into MOFs, MOF composites, and MOF derivatives The specific requirements of electrocatalysts for practical applications can sometimes be satisfied with the design of catalysts.…”

“…Highly efficient and stable electrocatalysts in acidic media can be realized by incorporation of M‐N‐C moieties or Pt‐based alloys into MOFs, MOF composites, and MOF derivatives …”