Search

Highly ordered multi-leg TiO2 nanotubes (MLTNTs) functionalized with platinized cyanographene are proposed as a hybrid photoelectrode for enhanced photoelectrochemical water splitting. The platinized cyanographene and cyanographene/MLTNTs composite yielded photocurrent densities 1.66 and 1.25 times higher than those of the pristine MLTNTs nanotubes, respectively. Open circuit VOC decay (VOCD), electrochemical impedance spectroscopy (EIS), and intensity-modulated photocurrent spectroscopy (IMPS) analyses were performed to study the recombination rate, charge transfer characteristics, and transfer time of photogenerated electrons, respectively. According to the VOCD and IMPS results, the addition of (platinized) cynographene decreased the recombination rate and the transfer time of photogenerated electrons by one order of magnitude. Furthermore, EIS results showed that the (platinized) cyanographene MLTNTs composite has the lowest charge transfer resistance and therefore the highest photoelectrochemical performance.

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.