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Bifunctional single atom electrocatalysts: coordination–performance correlations and reaction pathways

DOI: 10.1021/acsnano.0c05088 DOI Help

Authors: Wenchao Wan (University of Zurich) , Carlos A. Triana (University of Zurich) , Jinggang Lan (University of Zurich) , Jingguo Li (University of Zurich) , Christopher S. Allen (Diamond Light Source; University of Oxford) , Yonggui Zhao (University of Zurich) , Marcella Iannuzzi (University of Zurich) , Greta R. Patzke (University of Zurich)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Nano

State: Published (Approved)
Published: October 2020
Diamond Proposal Number(s): 16967

Abstract: Single atom catalysts (SACs) are ideal model systems in catalysis research. Here we employ SACs to address the fundamental catalytic challenge of generating well-defined active metal centers to elucidate their interactions with coordinating atoms, which define their catalytic performance. We introduce a soft-landing molecular strategy for tailored SACs based on metal phthalocyanines (MPcs, M = Ni, Co, Fe) on graphene oxide (GO) layers to generate well-defined model targets for mechanistic studies. The formation of electronic channels through π–π conjugation with the graphene sheets enhances the MPc-GO performance in both oxygen evolution and reduction reactions (OER and ORR). Density functional theory (DFT) calculations unravel that the outstanding ORR activity of FePc-GO among the series is due to the high affinity of Fe atoms toward O2 species. Operando X-ray absorption spectroscopy and DFT studies demonstrate that the OER performance of the catalysts relates to thermodynamic or kinetic control at low- or high-potential ranges, respectively. We furthermore provide evidence that the participation of ligating N and C atoms around the metal centers provides a wider selection of active OER sites for both NiPc-GO and CoPc-GO. Our strategy promotes the understanding of coordination–activity relationships of high-performance SACs and their optimization for different processes through tailored combinations of metal centers and suitable ligand environments.

Journal Keywords: single atom catalyst; graphene; phthalocyanine; water oxidation; oxygen reduction; operando X-ray absorption spectroscopy

Subject Areas: Chemistry

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