Tailoring Acidic Oxygen Reduction Selectivity on Single-Atom Catalysts via Modification of First and Second Coordination Spheres

Tang, Cheng; Chen, Ling; Li, Haijing; Li, Laiquan; Jiao, Yan; Zheng, Yao; Xu, Haolan; Davey, Kenneth; Qiao, Shi Zhang

doi:10.1021/jacs.1c03135

Cited by 509 publications

(485 citation statements)

References 47 publications

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“…This single-cell performance has been further boosted to 0.09 g Pt kW −1 on carbon-defect-anchored Pt SAC in a latest report 38 . These conflicting observations suggest that the ORR pathway and product selectivity on isolated Pt sites may be tailored by different reactivity of Pt central atom as arisen from different coordination environment 39 – 43 . How to address the above controversy, to correlate the apparent ORR performance with Pt-coordinated motifs at atomic level is therefore highly demanded.…”

Section: Introductionmentioning

confidence: 99%

Manipulating the oxygen reduction reaction pathway on Pt-coordinated motifs

Zhao

Yao

et al. 2022

Nat Commun

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Electrochemical oxygen reduction could proceed via either 4e−-pathway toward maximum chemical-to-electric energy conversion or 2e−-pathway toward onsite H2O2 production. Bulk Pt catalysts are known as the best monometallic materials catalyzing O2-to-H2O conversion, however, controversies on the reduction product selectivity are noted for atomic dispersed Pt catalysts. Here, we prepare a series of carbon supported Pt single atom catalyst with varied neighboring dopants and Pt site densities to investigate the local coordination environment effect on branching oxygen reduction pathway. Manipulation of 2e− or 4e− reduction pathways is demonstrated through modification of the Pt coordination environment from Pt-C to Pt-N-C and Pt-S-C, giving rise to a controlled H2O2 selectivity from 23.3% to 81.4% and a turnover frequency ratio of H2O2/H2O from 0.30 to 2.67 at 0.4 V versus reversible hydrogen electrode. Energetic analysis suggests both 2e− and 4e− pathways share a common intermediate of *OOH, Pt-C motif favors its dissociative reduction while Pt-S and Pt-N motifs prefer its direct protonation into H2O2. By taking the Pt-N-C catalyst as a stereotype, we further demonstrate that the maximum H2O2 selectivity can be manipulated from 70 to 20% with increasing Pt site density, providing hints for regulating the stepwise oxygen reduction in different application scenarios.

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Section: Introductionmentioning

confidence: 99%

Manipulating the oxygen reduction reaction pathway on Pt-coordinated motifs

Zhao

Yao

et al. 2022

Nat Commun

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“…However, if the coordinated atoms in the first coordination shell were partially replaced by O atoms, such as Co–N 2 O 2 , the active center was found to shift to the O-adjacent carbon atoms and H 2 O 2 becomes the preferred product. 42 Recently, in the investigation of the eNRR mechanism on Fe-decorated MoS 2 nanosheets, it was found that the active site is the Mo atoms along the Mo-edge of MoS 2 , rather than the deposited Fe single atoms. Nevertheless, the doping of the isolated Fe atoms can synergistically tune the eNRR activity and the selectivity toward ammonia.…”

Section: New Catalytic Mechanismsmentioning

confidence: 99%

Understanding Single-Atom Catalysis in View of Theory

Zhang

Luo

et al. 2021

JACS Au

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In the past decade, isolated single atoms have been successfully dispersed on various substrates, with their potential applications being intensively investigated in different reactions. While the essential target of research in single-atom catalysis is the precise synthesis of stable single-atom catalysts (SACs) with clear configurations and impressive catalytic performance, theoretical investigations have also played important roles in identifying active sites, revealing catalytic mechanisms, and establishing structure–activity relationships. Nevertheless, special attention should still be paid in theoretical works to the particularity of SACs. In this Perspective, we will summarize the theoretical progress made on the understanding of the rich phenomena in single-atom catalysis. We focus on the determination of local structures of SACs via comparison between experiments and simulations, the discovery of distinctive catalytic mechanisms induced by multiadsorption, synergetic effects, and dynamic evolutions, to name a few, the proposal of criteria for theoretically designing SACs, and the extension of original concepts of single-atom catalysis. We hope that this Perspective will inspire more in-depth thinking on future theoretical studies of SACs.

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“…Very recently, the same group constructed a CoNOC catalyst with N, O-dual coordination and C–O–C functional groups that demonstrated outstanding activity and a selectivity of >95% for acidic H 2 O 2 electrosynthesis relative to the CoN 4 site. 117 DFT computations, poisoning experiments, and in situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy suggested that an active site (especially for OOH* adsorption) shifted from the center Co atom to the O-adjacent C atom, enabling a superior 2e − ORR pathway ( Fig. 2g ).…”

Section: Engineering Of the M–n X Active Site For Enhancing The Intrinsic Activitymentioning

confidence: 99%