Vectorial carriers interfacial migration of Cd1-xZnxS heterophase junctions for visible-light water splitting

Cation exchange synthesis of porous Cd1‐xZnxS twinned nanosheets for visible light highly active H2 evolution

“…To the best of our knowledge, at the interface of ZB and WZ in Cd 0.5 Zn 0.5 S solid solution, the CB and VB energy levels of the WZ structure move up relative to the energy levels of the ZB structure, and these two structures can build a type-II phase junction located F I G U R E 1 0 Schematic illustration for the charge transfer and separation in Cd 0.5 Zn 0.5 S system and proposed mechanism for photocatalytic H 2 production under visible light irradiation in the twinned boundary, which results that the photogenerated electrons are effectively separated from the holes. 3,25,55 This is significantly different from most heterojunctions where electrons or holes can only be separated separately. 27,55 Based on the above analysis, Figure 10 gives the structural configuration and band positions for our porous Cd 0.5 Zn 0.5 S twinned nanosheets.…”

“…31,32 In addition to the important factor of high temperature, the presence of OH − in weakly alkaline DETA is another indispensable factor for the formation of twinned phase junctions, due to the unequal coordination ability between Zn 2+ /Cd 2+ and DETA leads to the difference in mass transfer among the principal reactants. 25,33 In order to determine the forma-tion of CdS and ZnS solid solution and exclude the possibility of phase separation, the elemental analysis by electron energy loss spectroscopy and EDS analysis were carried out (Figure 3E-J). Element mapping in Figure 3E-I shows that Cd, Zn, and S are evenly distributed in the porous Cd 0.5 Zn 0.5 S twinned nanosheets.…”

“…16,20 The zigzag structure in Figure 3D is the characteristic structure for a continuous nano twin structure with paralleled twin planes (marked in red line). 3,25 The lattice fringes paralleling to the twin plane with a spacing of 0.32 nm correspond to the <111> planes of the zinc blende (ZB) lattice. Atoms, which form the twin plane, show wurtzite (WZ) structure atom configuration with neighbor layer atoms.…”

“…Photogenerated holes converge in the valence band of the WZ phase to the twin plane and photooxidation occurs on the surface. 25,53 The enhancement of photocatalytic activity can be attributed to the designed Cd 0.5 Zn 0.5 S structure possessing both porous structure and nano twin structure, which can form an effective photocatalytic system. (i) The porous structure can remarkably abridge the path of electron transfer and broaden the light utilization by prolonging the time of light reaction in the pore walls.…”

“…23 In our previous study, twinned Cd 0.6 Zn 0.4 S nanoparticles with high photocatalytic activity were prepared by solvothermal method with thioacetamide as the sulfur source and triethanolamine as the solvent. 25 So far, there have only been a few reports on the synthesis of porous twinned nanosheets by the cation-exchange method. Here we employ the inorganic-organic hybrid semiconductor fakes as the precursor and develop a simply cation-exchange approach to fabricate porous twinned nanosheets.…”