AbstractBismuth vanadate (BiVO4) has been identified as one of the excellent visible-light-responsive photoanode for use in the photoelectrochemical water splitting. Recently intense research efforts have been devoted to the development of highly efficient BiVO4 photoanode. Herein, we reported a low-cost and scalable method for preparing nanostructured BiVO4 film. A much enhanced photocurrent (1.5 mA•cm−2) was obtained for such film, which was 6.5 times higher than that of planar film at 1.23 V [vs. RHE (Reversible Hydrogen Electrode)]. The method provides an eco-friendly, reproducible and facile way to scale up on different substrates with attractive potential.

The cover picture shows a vision of the large scale utilization of the bismuth vanadate photoanode in the water splitting. Bismuth vanadate, due to the appropriate valence band position and bandgap, has risen to be one of the most promising semiconductors for photoelectrochemical water splitting. The enlarged nanoporous bismuth vanadate photoanodes are prepared by chemical vapor deposition and subsequent calcination, which is facile, low-cost and non-toxic. The obtained photoanode with high carrier density and filling factor demonstrates excellent performance in photoelectrochemical water splitting and can be further enhanced by doping or coupling to oxygen evolution catalyst. This method paves a promising way for large-scale production of bismuth-based semiconductor films. More details are discussed in the article by Yang et al. on page 30–34.

AbstractDoping has been widely used to engineer efficient photocatalysts for the water-splitting process in energy conversion and storage systems. Although composition tuning through heteroatom doping is one of the strategies to enhance photoactivity, the origin of the increased activity by doping remains unclear and most illustrations of its role fall in the band engineering area. Herein, it is reported that the rhodium dopants on the surface of Zn2GeO4, which affect the band structure negligibly, can act as active sites for water splitting. As a result, the Rhδ+/Zn2GeO4 photocatalyst demonstrates excellent stability for up to 460 days and significant enhancement of the photocatalytic activity to that of the undoped photocatalyst. The findings in this work may open the door for a rethink of the detailed principles of dopants in photocatalysis, and highlight a feasible route to fabricating efficient photocatalysts.

•The α-Fe2O3 exposed by {012} and {104} facets can facilitate the reduction of IO3−.•The O2 evolution activity (309.4 μmol h−1 g−1) of α-Fe2O3 photocatalyst mainly exposed by {012} and {104} facets is 84 times higher than that (3.68 μmol h−1 g−1) of α-Fe2O3 mostly exposed by {101} and {111} planes.•This work may open the door for further development of enhanced Z-scheme photocatalytic systems.The mechanism study of redox mediator to transfer the photogenerated electrons is extremely desirable for artificial Z-scheme photocatalytic systems. Here we find that the α-Fe2O3 exposed by {012} and {104} facets can facilitate the reduction of IO3−, which results in increasing the activity of photocatalytic water oxidation significantly. By employing NaIO3 as an electron acceptor, the O2 evolution activity (309.4 μmol h−1 g−1) of α-Fe2O3 photocatalyst mainly exposed by {012} and {104} facets is 84 times higher than that (3.68 μmol h−1 g−1) of α-Fe2O3 mostly exposed by {101} and {111} planes. We anticipate that the findings in this work may open the door for further development of enhanced Z-scheme photocatalytic systems.Download high-res image (103KB)Download full-size image

•CNTs/Fe–Ni/TiO2 nanocomposites were synthesized by in situ FBCVD method.•CNTs were in situ grown on the surface of TiO2.•The sample synthesized at 500 °C exhibited best photocatalytic activity.•The probable mechanism of synergistic enhancement on photocatalysis was discussed.Carbon nanotube (CNTs)/Fe–Ni/TiO2 nanocomposite photocatalysts have been synthesized by an in situ fluidized bed chemical vapor deposition (FBCVD) method. The composite photocatalysts were characterized by XRD, Raman spectroscopy, BET, FESEM, TEM, UV–vis spectroscopy, and XPS. The results showed that the CNTs were grown in situ on the surface of TiO2. Fe(III) in TiO2 showed no chemical changes in the growth of CNTs. Ni(II) was partly reduced to metal Ni in the FBCVD process, and the metal Ni acted as a catalyst for the growth of CNTs. The photocatalytic activities of CNTs/Fe–Ni/TiO2 decreased with the rise of the FBCVD reaction temperature. For the sample synthesized at low FBCVD temperature (500 °C), more than 90% and nearly 50% of methylene blue were removed under UV irradiation in 180 min and under visible light irradiation in 300 min, respectively. The probable mechanism of synergistic enhancement of photocatalysis on the CNTs/Fe–Ni/TiO2 nanocomposite is proposed.

A uniformly distributed TiO2/CNTs composite film was fabricated by an in-situ chemical vapor deposition (CVD) method. CNTs are directly grown from the prepared TiO2 film by the spray pyrolysis deposition method doped with nickel oxide on Ni substrate. The nano-size TiO2 particles are uniformly distributed on the side walls of CNTs. The TiO2/CNTs composite exhibits high photocatalytic activity in the degradation of methyl orange (MO) and 95% of MO (10 mg/L) could be removed within 150 min under UV light irradiation. The results of the present study are promising for the development of a new method for the fabrication of well-distributed TiO2/CNTs compositefilm.Graphical abstractHighlights► In-situ growth of uniformly distributed TiO2/CNTs composite on Ni substrate by CVD. ► Uniformly distributed TiO2/CNTs composite exhibits good degradation of MO. ► Synergistic effect of uniformly distributed TiO2/CNTs is proposed.