Size‐Dependent Visible Light Photocatalytic Performance of Cu₂O Nanocubes

Abstract

Well‐defined Cu2O nanocubes with tunable dimensions and physicochemical properties have been prepared using a simple one‐pot reaction. Reduction of Cu(II) salts by ascorbic acid in the presence of PEG as a structure‐directing agent affords crystalline Cu2O nanocubes of between 50 to 500 nm. Optical band gap, band energies, charge‐carrier lifetimes and surface oxidation state systematically evolve with nanocube size, and correlate well with visible light photocatalytic activity for aqueous phase phenol degradation and H2 production which are both directly proportional to size (doubling between 50 and 500 nm). HPLC reveals fumaric acid as the primary organic product of phenol degradation, and selectivity increases with nanocube size at the expense of toxic catechol. Apparent quantum efficiencies reach 26 % for phenol photodegradation and 1.2 % for H2 production using 500 nm Cu2O cubes.

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 . Hydrogen production over the hierarchical Cu 2 O was superior to that of non‐porous (13 μmol.g −1 .h −1 ) and Cu 2 O nanoparticles (10 μmol.g −1 .h −1 ) of comparable size, and the AQE higher than reported for Pt‐decorated 500 nm Cu 2 O nanocubes (AQE=1.2 %), 375 nm hierarchical Cu 2 O nanocubes (AQE=1.2 %), and Pt‐free 300–500 nm Cu 2 O powder (AQE=0.3 %) and 150 nm Cu 2 O nanostructures on a silicon wafer (AQE in water=0.3 %) under visible light, demonstrating advantageous photophysical properties of our Pompom Dahlia‐like aggregates. Hydrogen production over various Cu 2 O photocatalysts is summarised in Table S3.…”

“…Various structural modifications of Cu 2 O have been investigated to overcome these limitations, with different morphologies such as nano‐wires, cubes, flowers, and spheres, offering significant improvements in photophysical properties for photocatalytic applications. Size and morphology of Cu 2 O nanostructures determine their resulting chemical and physical properties . Hierarchical semiconductors have gained recent interest as they can offer additional control of electronic and optical properties .…”

“…Size and morphology of Cu 2 O nanostructures determine their resulting chemical and physical properties. [16] Hierarchical semiconductors have gained recent interest as they can offer additional control of electronic and optical properties. [17] We reported a hierarchical Cu 2 O photocatalyst comprised of individual nanoparticles assembled into porous nanocubes that exhibited a promising hydrogen productivity (water splitting) 15 μmol.g À 1 .h À 1 corresponding to an apparent quantum efficiency (A.Q.E) of 1.2 % in the presence of a Pt co-catalyst.…”

Glycine–Nitrate Combustion Synthesis of Cu-Based Nanoparticles for NP9EO Degradation Applications

“…This study will provide useful evidence on the potential of this method as a treatment to remove toxic materials from the water environment. [22]. In addition, the peaks at 50.5 • and 74.2 • , which corresponded to the (200) and (220) peaks, respectively, of zero-valent copper (Cu 0 ) were observed.…”

Green Synthesis of a Cu/SiO2 Catalyst for Efficient H2-SCR of NO

“…The advantages of these routes are well documented, and the synthesis of catalysts from a suspension of the active metal with nanometric size might turn out to be profitable [26][27][28][29][30][31][32]. Taking into account the synthesis of metal nanoparticles, there exists a large number of protocols that report the chemical reduction of the metallic precursor in solution as the most promising alternative approach [26,33,34].…”