Promotion of oxygen reduction on a porphyrazine-modified Pt catalyst surface

Catalyst overcoating engineering towards high-performance electrocatalysis

“…Typically, surface engineering of Pt with a hydrophobic ionic liquid layer has been considered as the effective strategy to efficiently destabilize OH ad species and repel water from the surface intermediates and products while maintaining the accessibility of active sites to the reactants, resulting in high resistance of the catalyst to surface oxidation and thus accelerated ORR activities. 63,[225][226][227] In the work reported by Snyder et al, 226 markedly improved ORR kinetics in performance was observed on nanoporous NiPt nanoparticles encapsulated by a hydrophobic, protic ionic liquid (IL, [MTBD][beti]) (Fig. 9f and g).…”

“…2c, d and f). [58][59][60][61][62][63][64] As such, chemically adsorbed or assembled organic molecules with tunable coverage on the surface of the metal are generated. Similar to the direct colloidal reduction synthesis, this strategy relies on the fact that organic molecules are prone to chemically coordinate with metal entities on the surface.…”

“…As earlier reported by Markovic ´'s group, patterning Pt with a self-assembled monolayer of calix [4]arene molecules featuring a wide rim structure endowed the catalyst with a high selectivity for the HOR. 63,64 High occupation of Pt by the calix layer could not change HOR activity since it has fast kinetics in an acidic electrolyte. In contrast, the ORR was inhibited because of the insufficient sites for O 2 adsorption and O-O bond cleavage on the Pt surface following the organic patterning.…”

Surface Modification for Promoting Durable, Efficient, and Selective Electrocatalysts

“…The presence of organic ligands at the Pt surfaces is likely to impact the adsorption and dissociation energetics of O 2 and oxygenated intermediates (O*, OH*, OOH*, HOO*) that govern the activity and selectivity of the electrocatalytic processes, whatever the underlying associated mechanisms . A wide range of organic compounds such as surfactants, polymers, capping ligands or adsorbed macrocycles were demonstrated to tune the reactivity of Pt nanoparticles.…”

Mesostructured cellular foam silica supported Au–Pt nanoalloy: Enrichment of d-state electrons for promoting the catalytic synergy

“…Noble metal nanoparticles (NPs) such as Au, Pt, Pd, Ru, Rh are receiving extensive attention due to their important applications in heterogeneous catalysis [1][2][3][4], sensors [5,6], electronics [7][8][9] and biology [10,11]. In the case of catalysts based on noble metal nanoparticles, two important aspects were usually investigated, geometrical and electronic effects, which are related to particle size [12], metal-support interactions [13][14][15], chemical compositions [16,17], promoter effects [18,19], etc.…”