Crystal Faces of Cu₂O and Their Stabilities in Photocatalytic Reactions

Abstract

Cu 2 O microcrystals with well-formed facets were synthesized by a simple hydrothermal method. The surface stabilities and photocatalytic properties of Cu 2 O microcrystals were systematically investigated. Cu 2 O {100} and {110} facets gradually disappear and transform into nanosheets during the photodegradation of methyl orange (MO) dye. With the increase of irradiation time, Cu 2 O microcrystals completely transform into nanosheets with {111} facets. The finally formed nanosheets exhibit stable photocatalytic activities. On the basis of both experimental analysis and theoretical calculations, a novel model of charge separation among crystal faces was proposed and the morphology transformation mechanism accompanied by MO bleaching was discussed. It is concluded that Cu 2 O exposing {111} facets can be used as a stable photocatalyst.

The effect of different exposed facets on the photoelectrocatalytic degradation of o-chlorophenol using p-type Cu 2 O crystals

“…The synthesis of Cu 2 O micro or nanostructures with controllable morphologies has been developed [14,15], including nanocubes [15,16], octahedra [15,16], polyhedral morphology [17], hollow structures [18] and nanowires [19], and many growth mechanisms have been proposed. These Cu 2 O microcrystals were generally synthesized by hydrothermal methods in the presence of different capping reagents (e.g., surfactant [20], ascorbic acid or hydrazine hydrate [16], and acetic acid [17]). The photodegradation of organic pollutants in a suspended catalyst system would cause several problems, such as difficulty in the recovery of photocatalysts, easy agglomeration and decreased active surface, low efficiency and the risk of secondary pollution.…”

Inquiring the photocatalytic activity of cuprous oxide nanoparticles synthesized by a green route on methylene blue dye

“…Among the various semiconductor metal oxides as photocatalyst, Cu 2 O NPs find a special place in photocatalysis under visible light [10][11][12][14][15][16]. Wide applications of this oxide NPs are mainly owing to its nontoxicity, easy availability of cheap and up-scalable synthetic routes, lying of the band gap (i.e., 2.17 eV) in the visible range, tunability of band gap, and strong tendency to adsorb molecular oxygen which helps in scavenging the photogenerated electrons so that electron-hole pairs recombination can be restrained easily at the interface [10][11][12][14][15][16].…”

“…Wide applications of this oxide NPs are mainly owing to its nontoxicity, easy availability of cheap and up-scalable synthetic routes, lying of the band gap (i.e., 2.17 eV) in the visible range, tunability of band gap, and strong tendency to adsorb molecular oxygen which helps in scavenging the photogenerated electrons so that electron-hole pairs recombination can be restrained easily at the interface [10][11][12][14][15][16]. It is reported that size and shape are of paramount importance in tailoring the various properties and applications of the Cu 2 O NPs.…”

“…A variety of Cu 2 O nanostructures such as wires, boxes, cubes, truncated cubes, octahedra, nanocages, nanomultipods, spheres, and a variety of hollow structures have already been synthesized and tested for their photocatalytic activity on various organic compounds [14,15]. To develop diverse architectures of Cu 2 O, the various methods widely used includes hydrothermal method, microemulsion method, surfactantassisted route, and wet chemical method [10][11][12][14][15][16]. Sun et al [9] have reported an enhanced photocatalytic activity for Cu 2 O-graphene oxide (GO) nanocomposite synthesized via solvothermal route towards Rhodamine B (RhB) dye.…”

“…In another article, Zhang et al [11] A few reports are available on photocatalytic activity study of Cu 2 O NPs synthesized by green chemical route. Cu 2 O microcrystals with well-formed facets were synthesized by a simple hydrothermal method by Zheng et al [14] and investigated the surface stabilities and photocatalytic properties of the synthesized Cu 2 O microcrystals. It is reported that Cu 2 O {100} and {110} facets gradually disappear and transform into nanosheets during the photodegradation of MO dye.…”