Structural Modulation of Co Catalyzed Carbon Nanotubes with Cu–Co Bimetal Active Center to Inspire Oxygen Reduction Reaction

Abstract

Rational design of highly efficient catalyst for ORR is critical for development of advanced air cathode in Zn−air cells and fuel cells. To optimize the ORR performance of Co based cathode, the structure of carbon nanotube from DCI-Co precursor could be controlled through modulate synthetic parameters. The optimized ORR catalyst Co@NCNT-700 exhibit larger BET area, higher content of Co−N x and graphitic N, which performance could be improved in further through Cu doping. The experiment data approved that the activity of Co−N x was enhanced by the synergistic effect with introduced Cu. Furthermore, the high-performance zinc-air batteries was fabricated with the bimetal catalyst CuCo@NCNT-700 as an air electrode. The high open-cycle potential (1.54 V) and peak power density (0.275 W.cm −2 at 0.474 A.cm −2 ) were achieved, which would be potentially used to develop next generation energy conversion devices.

Strong coupled spinel oxide with N-rGO for high-efficiency ORR/OER bifunctional electrocatalyst of Zn-air batteries

“…The projected density of states (PDOS) in Fig. 5(c) also reveals that Co is the active site, because of the large overlap between the d orbital of Co and the p orbital of O 2 [18,35]. Then, the effect of N doping was explored by comparing the properties of composite structures with or without N dopants (ZnCoMnO 4 / N-rGO and ZnCoMnO 4 /rGO).…”

Electrochemical Dealloying-Assisted Surface-Engineered Pd-Based Bifunctional Electrocatalyst for Formic Acid Oxidation and Oxygen Reduction

“…Furthermore, the scarcity of Pt and the lack of durability are some of the other major concerns with Pt-based catalysts. Synthesis of non-Pt electrocatalyst is of recent interest, and much effort has been devoted to the development of non-Pt metallic alloy-based and metal-free electrocatalyst. − Although U.S. Department of Energy set the 2017 target ORR mass activity of 0.44 A/mg Pt , the non-Pt electrocatalysts could not deliver the target value . For instance, non-Pt catalysts such as Pd–Rh, Au–Rh, Rh–Sn, etc.…”

Ni/Cu Regulating Nitrogen‐Doped Porous Carbon as Electrocatalyst for Oxygen Reduction Reaction

“…Density functional theory (DFT) calculations have been used to further investigate the ORR mechanism and synergistic effect of bimetallic Ni/Cu of Ni 1‐x Cu x ‐N−C. Despite that encapsulated metal or alloy nanoparticles have been suggested to active the surrounding N doped carbon layers, making them active toward ORR, M‐N x species are generally believed as the primary ORR active sites [10,31] . For simplicity, Ni−N 4 , Cu−N 4 and Ni−Cu−N 6 are adopted as active site models for theoretical simulations for Ni−N−C, Cu−N−C, and bimetallic Ni−Cu−N/C, respectively (Figure S11), since such motifs are proved to be active and stable for ORR on M−N−C catalysts [32–34] .…”

“…Density functional theory (DFT) calculations have been used to further investigate the ORR mechanism and synergistic effect of bimetallic Ni/Cu of Ni 1-x Cu x -NÀ C. Despite that encapsulated metal or alloy nanoparticles have been suggested to active the surrounding N doped carbon layers, making them active toward ORR, M-N x species are generally believed as the primary ORR active sites. [10,31] For simplicity, NiÀ N 4 , CuÀ N 4 and NiÀ CuÀ N 6 are adopted as active site models for theoretical simulations for NiÀ NÀ C, CuÀ NÀ C, and bimetallic NiÀ CuÀ N/C, respectively (Figure S11), since such motifs are proved to be active and stable for ORR on MÀ NÀ C catalysts. [32][33][34] As shown in Figure S12a and b, the O 2 molecules adsorbed on Ni-N 4 and Cu-N 4 centers are both in the end-on configuration, and their adsorption free energies (ΔG O2* ) are À 0.015 eV and À 0.017 eV, respectively, which indicates the weak physical adsorption.…”