Spatial charge separation between wurtzite CdS polar (0001) and (0001¯) facets and their enhanced visible-light photocatalytic activity

Photogenerated Charge Separation between Polar Crystal Facets Under a Spontaneous Electric Field

“…[ 15 ] . Recently, the ZnO {001} polar planes have been found to have enhanced photocatalytic CO 2 reduction activity, [ 22 ] In addition to ZnO{001}, hexagonal phase CdS{001}, [ 23–26 ] CdSe{001} [ 27 ] and Cu‐Zn‐In‐S{001}, [ 28 ] cubic phase CoO{111}, [ 29 ] CdTe{111}, [ 30 ] NiO{111}, [ 31 ] Cu 2 O{111}, [ 32,33 ] Cu 2 Se{111}, [ 34 ] Cu 2 O/Cu 2 Se{111}, [ 35 ] and Zn 0.67 Cd 0.33 S{111} [ 36 ] as well as tetragonal phase anatase TiO 2 {111} [ 37,38 ] crystal facets have been reported to be the reactive surfaces for photocatalytic decomposition of organic dyes, [ 23,24,27,29–33 ] photocatalytic H 2 generation [ 25,26,28,35–37 ] and CO 2 reduction. [ 38 ]…”

“…Reproduced with permission. [ 24 ] Copyright 2017, Elsevier. f,g) CoO{111}.…”

“…We have investigated the structures at atomic scale of the hexagonal phase CdS{001}, [ 24 ] cubic phase CoO{111}, [ 29 ] CdTe{111}, [ 30 ] NiO{111}, [ 31 ] Cu 2 Se{111}, [ 34 ] Cu 2 O{111}, [ 32,33 ] and Cu 2 O/Cu 2 Se{111} [ 35 ] and tetragonal phase anatase TiO 2 {111} [ 38 ] crystallographic facets by periodic density functional theory (DFT) calculation, the result is shown in Figure 1d–p. It is found that the exposed photocatalytic active facets are completely polar surfaces.…”

“…It is found that the exposed photocatalytic active facets are completely polar surfaces. According to the model of charge separation between ZnO polar facets, the enhanced photocatalytic mechanisms for the decomposition of organic dyes of the CdS {001}, [ 24 ] CoO{111}, [ 29 ] CdTe{111}, [ 30 ] NiO{111}, [ 31 ] and Cu 2 Se{111} [ 34 ] crystal planes, the enhanced photocatalytic mechanisms for H 2 generation of the Cu 2 O/Cu 2 Se{111} [ 35 ] crystal planes and the enhanced photocatalytic mechanisms for CO 2 reduction of TiO 2 {111} [ 38 ] crystal facets have been described. The hexagonal phase ZnO and CdSe are all similar in structure.…”

“…[ 1,42,43 ] At the nonmetallic‐atom‐terminated surfaces, the photocreated holes react with OH − /H 2 O to produce hydroxyl radicals ( · OH). Finally, the pollutant molecules are oxidized by the · OH radicals into H 2 O, CO 2 , and mineralization products, [ 1,24,27,29–31,34 ] as shown in Figure 2b. For the photocatalytic H 2 generation, at the metallic‐atom‐terminated surfaces, H + ions react with photo‐produced electrons to form H 2 .…”