Oriented 2.0.0 Cu2O nanoplatelets supported on few-layers graphene as efficient visible light photocatalyst for overall water splitting

Abstract

Cu2O nanoplatelets with preferential 2.0.0 facet orientation supported on few layers graphene were prepared as films in a single step by pyrolysis at 900 o C under inert atmosphere of Cu 2+-chitosan precursor. /fl-G films exhibit a photocatalytic activity for overall water splitting of 19.5 mmol/gCu+G•h. This value is about 4 orders of magnitude higher than the photocatalytic activity measured for unoriented Cu2O nanoparticles on few-layers graphene or than commercial Cu2O nanoparticles and about three orders of magnitude higher than the activity reported in the literature for Cu2O nanoparticles. In addition Cu2O nanoparticles on few-layers graphene retain about 50 % of its photocatalytic activity after 6 days of continuous irradiation. It is proposed that this activity and stability arises from the combination of features derived from the pyrolysis preparation procedure including strong Cu2O-graphene grafting, the role of graphene as cocatalyst and preferential 2.0.0 facet orientation.

Oriented Au nanoplatelets on graphene promote Suzuki-Miyaura coupling with higher efficiency and different reactivity pattern than supported palladium

“…In addition, other factor that should be playing a role is the crystallographic orientation of Au nanoplatelets in the 111 facet and the possible steps on the platelets. Whatever the origin of this remarkable catalytic activity for ���� /fl-G, it agrees with already observations on a remarkably high activity of metal NPs (Au, Pt and Cu) grafted on G prepared by pyrolysis for homocouplings, oxidations and as photocatalysts [35][36][37]42].…”

Pompon Dahlia‐like Cu2O/rGO Nanostructures for Visible Light Photocatalytic H2 Production and 4‐Chlorophenol Degradation

“…Interfacing the Cu 2 O semiconductor with rGO nanosheets to form a heterojunction almost doubles the specific activity, consistent with greater visible light absorption. [42] Hydrogen production over the hierarchical Cu 2 O was superior to that of non-porous (13 μmol.g À 1 .h À 1 ) [43] and Cu 2 O nanoparticles (10 μmol.g À 1 .h À 1 ) [7] of comparable size, and the AQE higher than reported for Pt-decorated 500 nm Cu 2 O nanocubes (AQE = 1.2 %), [41b] 375 nm hierarchical Cu 2 O nanocubes (AQE = 1.2 %), [44] and Pt-free 300-500 nm Cu 2 O powder (AQE = 0.3 %) [7] and 150 nm Cu 2 O nanostructures on a silicon wafer (AQE in water = 0.3 %) under visible light, [45] demonstrating advantageous photophysical properties of our Pompom Dahlia-like aggregates. Hydrogen production over various Cu 2 O photocatalysts is summarised in Table S3.…”

Photocatalysis for Hydrogen Production and CO2 Reduction: The Case of Copper‐Catalysts

“…Owning to the difference of the [100] and [111] facets CB and VB position, photogenerated charges were effectively separated in mix‐faceted Cu 2 O materials, improving H 2 production . Cu 2 O with preferential exposed facets has been successfully grown on graphene of few layers and presented higher photocatalytic H 2 production with respect to un‐oriented Cu 2 O nanoparticles or commercial Cu 2 O . In addition, while un‐supported Cu 2 O particles are very unstable during H 2 photoproduction (rapid oxidation of Cu 2 O to CuO), the presence of few layers of graphene in the composite increased significantly the stability of Cu 2 O particles through the strong Cu 2 O‐graphene interaction.…”