TY - JOUR
T1 - Engineering three-dimensional (3d) out-of-plane graphene edge sites for highly selective two-electron oxygen reduction electrocatalysis
AU - San Roman, Daniel
AU - Krishnamurthy, Dilip
AU - Garg, Raghav
AU - Hafiz, Hasnain
AU - Lamparski, Michael
AU - Nuhfer, Noel T.
AU - Meunier, Vincent
AU - Viswanathan, Venkatasubramanian
AU - Cohen-Karni, Tzahi
N1 - Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/2/7
Y1 - 2020/2/7
N2 - Selective two-electron oxygen reduction reaction (ORR) offers a promising route for hydrogen peroxide synthesis, and defective sp2-carbon-based materials are attractive, low-cost electrocatalysts for this process. However, due to a wide range of possible defect structures formed during material synthesis, the identification and fabrication of precise active sites remain a challenge. Here, we report a graphene edge-based electrocatalyst for two-electron ORR - nanowire-templated three-dimensional fuzzy graphene (NT-3DFG). NT-3DFG exhibits notable efficiency [onset potential of 0.79 ± 0.01 V vs reversible hydrogen electrode (RHE)], high selectivity (94 ± 2% H2O2), and tunable ORR activity as a function of graphene edge site density. Using spectroscopic surface characterization and density functional theory calculations, we find that NT-3DFG edge sites are readily functionalized by carbonyl (C═O) and hydroxyl (C-OH) groups under alkaline ORR conditions. Our calculations indicate that multiple functionalized configurations at both armchair and zigzag edges may achieve a local coordination environment that allows selective, two-electron ORR. We derive a generalized geometric descriptor based on the local coordination environment that provides activity predictions of graphene surface sites within ∼0.1 V of computed values. We combine synthesis, spectroscopy, and simulations to improve active site characterization and accelerate carbon-based electrocatalyst discovery.
AB - Selective two-electron oxygen reduction reaction (ORR) offers a promising route for hydrogen peroxide synthesis, and defective sp2-carbon-based materials are attractive, low-cost electrocatalysts for this process. However, due to a wide range of possible defect structures formed during material synthesis, the identification and fabrication of precise active sites remain a challenge. Here, we report a graphene edge-based electrocatalyst for two-electron ORR - nanowire-templated three-dimensional fuzzy graphene (NT-3DFG). NT-3DFG exhibits notable efficiency [onset potential of 0.79 ± 0.01 V vs reversible hydrogen electrode (RHE)], high selectivity (94 ± 2% H2O2), and tunable ORR activity as a function of graphene edge site density. Using spectroscopic surface characterization and density functional theory calculations, we find that NT-3DFG edge sites are readily functionalized by carbonyl (C═O) and hydroxyl (C-OH) groups under alkaline ORR conditions. Our calculations indicate that multiple functionalized configurations at both armchair and zigzag edges may achieve a local coordination environment that allows selective, two-electron ORR. We derive a generalized geometric descriptor based on the local coordination environment that provides activity predictions of graphene surface sites within ∼0.1 V of computed values. We combine synthesis, spectroscopy, and simulations to improve active site characterization and accelerate carbon-based electrocatalyst discovery.
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U2 - 10.1021/acscatal.9b03919
DO - 10.1021/acscatal.9b03919
M3 - Article
AN - SCOPUS:85078920714
SN - 2155-5435
VL - 10
SP - 1993
EP - 2008
JO - ACS Catalysis
JF - ACS Catalysis
IS - 3
ER -