Anchoring of single-platinum-adatoms on cyanographene: Experiment and theory

Abstract

Graphene decorated with isolated single atoms (SAs) offers new vista to magnetic and spintronic devices up to single-atom catalysts. While sp atoms can be efficiently bound to graphene, d-block atoms require anchoring groups to prevent nanoparticle formation. Identification of suitable binding sites is a challenging task because the interaction among graphene, anchoring groups and adatoms is very complex. Using density functional theory (DFT) we explored strength and nature of interactions of graphene covalently functionalized by − OH, − CN, − F, and − H groups as anchors for Pt SAs. Both theory and experiment showed that − CN groups acted as suitable ligand enabling immobilization of 3.7 wt % single Pt adatoms. The findings imply that CN functionalized graphene, i.e., cyanographene, is a perspective material for anchoring metal adatoms with potential implications as single-atom-catalysts.

Multi-Leg TiO2 Nanotube Photoelectrodes Modified by Platinized Cyanographene with Enhanced Photoelectrochemical Performance

“…This is higher than the typical binding energies for bulk metallic Pt (371 eV). Nevertheless, such positive shifts have been observed in ultra-small particles of Pt [48], particularly when interacting with nitrogen atoms [49], as in the present case. G-CN/Pt contained 2.3 wt.…”

“…Cyanographene (G-CN) showed the typical layered structure of fluorographene-derived functionalized graphenes [42,47] (Figure 1a). The microwave assisted homogeneous deposition of single Pt 2+ ions on G-CN has also been previously confirmed in detail by high resolution electron microscopy (TEM), sub-Angstrom resolution aberration-corrected high-angle annular dark-field scanning TEM and chemical mapping with energy dispersive X-ray spectroscopy [48]. After the reduction with NaBH 4 , ultrasmall Pt nanoparticles were clearly formed (Figure 1b-d), with 98% of the particles having diameters between 0.5 to 2 nm.…”

“…The synthesis process of the G-CN was described elsewhere [43] as well as the immobilization of Pt 2+ ions [48]. Briefly, 100 mg of G-CN was dispersed by sonication (15 min, Branson 2510, Danbury, CT, USA, 100W, 45 kHz) in 10 mL of water.…”

Hydrogen Evolution Reaction-From Single Crystal to Single Atom Catalysts

“…In SACs the role of the support becomes more profound as each isolated atom lies at the border between the support and metal 'phase'. The strategy of stabilizing single atoms on carbon (and other) carriers involves providing anchoring groups or defects acting as ligands for the metal atoms [187,188]. These ligands act as Lewis bases binding the metal center and inherently poses H affinity if not saturated by bonding to the metal atom.…”

Hydrogen Evolution Reaction - From Single Crystal to Single Atom Catalysts

“…In SAHCs the role of the support becomes more profound as each isolated atom lies at the border between the support and metal 'phase'. The strategy of stabilizing single atoms on carbon (and other) carriers involves providing anchoring groups or defects acting as ligands for the metal atoms [174,175]. These ligands act as Lewis bases binding the metal center and inherently poses H Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 16 February 2020 doi:10.20944/preprints202002.0215.v1 affinity if not saturated by bonding to the metal atom.…”