Indium oxide-based Z-scheme hollow core-shell heterostructure with rich sulfur-vacancy for highly efficient light-driven splitting of water to produce clean energy.

Crafting an inorganic semiconductor heterojunction with defect engineering and morphology modulation is a strategic approach to produce clean energy by the highly efficient light-driven splitting of water. In this paper, a novel Z-scheme sulfur-vacancy containing Zn3In2S6 (Vs-Zn3In2S6) nanosheets/In2O3 hollow hexagonal prisms heterostructrue (Vs-ZIS6INO) was firstly constructed by an oil bath method, in which Vs-Zn3In2S6 nanosheets grew on the surfaces of In2O3 hollow hexagonal prisms to form a hollow core-shell structure. The obtained Vs-ZIS6INO heterostructrue exhibited much enhanced activity of the production of H2 and H2O2 by the light-driven water splitting. In particular, under visible light irradiation (λ > 420 nm), the rate of generation of H2 of Vs-ZIS6INO sample containing 30 wt% Vs-Zn3In2S6 (30Vs-ZIS6INO) could reach 3721 µmol g-1h-1, which was 87 and 6 times higher than those of Zn3In2S6 (43 µmol g-1h-1) and Vs-Zn3In2S6 (586 µmol g-1h-1), respectively. Meanwhile, 30Vs-ZIS6INO could exhibit the rate of H2O2 production of 483 µmol g-1h-1 through the dual pathways of indirect 2e- oxygen reduction (ORR) and water oxidation (WOR) without adding any sacrifice agents, far exceeding In2O3 (7 µmol g-1h-1) and Vs-Zn3In2S6 (58 µmol g-1h-1). The excellent photocatalytic activities of H2 and H2O2 generations of Vs-ZIS6INO sample might result from the synergistic effect of the sulfur vacancy, hollow core-shell structure, and Z-scheme heterostructure, which accelerated the electron delocalization, enhanced the absorption and conversion of solar energy, reduced the carrier diffusion distance, and ensured high REDOX ability. In addition, the possible photocatalytic mechanisms for the production of H2 and H2O2 were discussed in detail. This study provided a new idea and reference for constructing the novel and efficient inorganic semiconductor heterostructures by coordinating vacancy defect and morphology design to adequately utilize water splitting for the production of clean energy.

Conductive Polymer-Inorganic Polythiophene/Cd0.5Zn0.5S Heterojunction with Apace Charge Separation and Strong Light Absorption for Boosting Photocatalytic Activity.

In order to utilize the synergistic effect between a conductive polymer and an inorganic semiconductor to efficaciously enhance charge transfer and solve the problem of unsatisfactory performance of a single photocatalyst, thiophene (Th) was polymerized on the Cd0.5Zn0.5S nanoparticle surface to prepare a conductive polymer-inorganic polythiophene/Cd0.5Zn0.5S (PTh/CZS) heterostructrue through a simple in situ oxidation polymerization for the first time. The as-prepared PTh/CZS heterostructures significantly improved photocatalytic TCH degradation and hydrogen production activities. Especially, the 15PTh/CZS sample exhibited the optimal hydrogen production rate (18.45 mmol g-1 h-1), which was 2.51 times higher than pure Cd0.5Zn0.5S nanoparticles. In addition, 15PTh/CZS also showed very fast and efficient photodegradation ability for degrading 88% of TCH in 25 min. Moreover, the degradation rate (0.06229 min-1) was five times more than that of Cd0.5Zn0.5S. The π-π* transition characteristics, high optical absorption coefficient, wide absorption wavelength of PTh, the tight contact interface, and synergistic effect of PTh and Cd0.5Zn0.5S efficiently boosted charge transfer rate and increased the light absorption of PTh/CZS photocatalysts, which greatly enhanced the photocatalytic abilities. Besides, the mechanism of improved photocatalytic activities for TCH degradation and H2 production was also carefully proposed. Undoubtedly, this work would provide new insights into coupling conductive polymers to inorganic photocatalysts for achieving multifunctional applications in the field of photocatalysis.

The electronic structure of carbones revealed: insights from valence bond theory.

In this contribution, we studied the OC-C bond in carbon suboxide and related allene compounds using the valence bond method. The nature of this bond has been the subject of debate, whether it is a regular, electron sharing bond or a dative bond. We compared the nature of this bond in carbon suboxide with the gold-CO bond in Au(CO)2+, which is a typical dative bond, and we studied its charge-shift bond character. We found that the C-CO bond in carbon suboxide is unique in the sense that it cannot be assigned as either a dative or electron sharing bond, but it is an admixture of electron sharing and dative components, together with a high contribution of ionic character. These findings provide a clear basis for distinguishing the commonly found dative bonds between ligands and transition metals and the present case of what may be described as coordinative bonding to carbon.