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A direct Z-scheme photocatalyst Bi2O3/g-C3N4 was prepared by ball milling and heat treatment methods. The photocatalyst was characterized by X-ray powder diffraction (XRD), UV-vis diffuse reflection spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface areas, photoluminescence technique (PL), and electron spin resonance (ESR) technology. The photocatalytic activity was evaluated by degradation of methylene blue (MB) and rhodamine B (RhB). The results showed that Bi2O3/g-C3N4 exhibited a much higher photocatalytic activity than pure g-C3N4 under visible light illumination. The rate constants of MB and RhB degradation for Bi2O3(1.0wt.%)/g-C3N4 are about 3.4 and 5 times that of pure g-C3N4, respectively. The migration of photogenerated carriers adopts a Z-scheme mechanism. The photoexcited electrons in the CB of Bi2O3 and photogenerated holes in the VB of g-C3N4 are quickly combined, so the photoexcited electrons in the CB of g-C3N4 and holes in the VB of Bi2O3 participate in reduction and oxidation reactions, respectively. O2(-), OH and h(+) are the major reactive species for the Bi2O3/g-C3N4 photocatalytic system., (Copyright © 2014 Elsevier B.V. All rights reserved.)

BiVO4 possesses a suitable band gap for photoelectrochemical (PEC) water splitting to produce hydrogen; however, the performance of BiVO4 is limited by several adverse factors. The bulk charge recombination and the slow surface water oxidation reaction of BiVO4 are main unfavorable factors. In view of these disadvantages, an Fe–Bi electrocatalyst is loaded on BiVO4 to improve the PEC performance of BiVO4. After modification, the onset potential of BiVO4 shifts negatively by 60 mV, and the saturated photocurrent is greatly increased. Systematic studies demonstrate that the Fe–Bi electrocatalyst not only enhances the bulk charge separation, but also accelerates the surface water oxidation rate of BiVO4 and greatly reduces the resistance of the reaction interface. [ABSTRACT FROM AUTHOR]

Exploring cheap and efficient cocatalysts is particularly important for a photoanode during photoelectrochemical (PEC) water splitting. Herein, we demonstrate that composite CoOx/CuO cocatalyst could efficiently enhance the oxygen evolution activity of BiVO4. The onset potential of BiVO4 shifts negatively from 0.42 to 0.38 V vs. the reversible hydrogen electrode (RHE), and the photocurrent of BiVO4 increases from 0.42 mA cm−2 to 1.58 mA cm−2 at 1.23 V vs. RHE, which increases by about 3.76 times. It was confirmed by subsequent electrochemical and physical characterization that the charge separation and injection efficiency were improved, and the IPCE was also improved. Systematic studies indicate that composite CoOx/CuO cocatalyst exhibits better performance than the single CoOx or CuO cocatalyst for promoting the separation of electron‐hole, and accelerating the surface water oxidation reaction. [ABSTRACT FROM AUTHOR]

BiVO has emerged as a promising material for solar water splitting. The poor ability of charge transport and separation always limits its performance for photoelectrochemical water splitting. Herein, we coupled n-type BiVO with p-type LaFeO and LaCoO, achieving a photocurrent more than two times as high as bare BiVO at 1.23 V versus a reversible hydrogen electrode. Also, the onset potential was negatively shifted about 260 mV. The promotion of performance is mainly because the space charge layer in BiVO is broadened, and the band bend is enhanced, which facilitates the separation and transport of photo-generated charges. [ABSTRACT FROM AUTHOR]

Photoelectrochemical oxidation of methyl phenyl sulfide with water as the only oxygen source is achieved on Mo-BiVO 4 photoanode. Mo-BiVO 4 photoelectrode performs oxygen transfer reaction in PEC oxidation of MPS. [Display omitted] • Mo-BiVO 4 photoelectrode was applied to oxidation of methyl phenyl sulfide. • PEC oxygen atom transfer (OAT) reaction was achieved on Mo-BiVO 4 photoelectrode. • Isotopic labelling experiment with H 2 18O revealed oxygen atoms in MPSO were mainly from water. Photoelectrochemical (PEC) selective oxidation is an environment-friendly strategy to obtain value-added chemicals. Herein, we report the PEC oxidation of methyl phenyl sulfide (MPS) into methyl phenyl sulfoxide (MPSO) with 85.7 % selectivity and 36.2 % conversion on molybdenum doped bismuth vanadate (Mo-BiVO 4) photoelectrode under simulated sunlight illumination (AM 1.5 G, 100 mW cm−2). Isotopic labelling experiment with H 2 18O was conducted to clearly reveal that the oxygen atoms in the MPSO were mainly from water. Based on these results, the application of Mo-BiVO 4 has been extended to PEC selective oxidation. [ABSTRACT FROM AUTHOR]

Bismuth vanadate photoanodes often suffer from poor electron transport, which restricts their photoelectrochemical performance in water oxidation. Here, reduced graphene oxide sheets with excellent electronic conductivity are introduced to bismuth vanadate photoanode films to provide a channel for electron transport. As a result, the charge separation efficiency of the photoanode films increases from 59 to 78 % at 420 nm and 1.23 V (vs. the reversible hydrogen electrode) under back irradiation. In particular, the onset potential for photoelectrochemical water oxidation over reduced graphene oxide-bismuth vanadate photoanode films has a cathodic shift of approximately 120 mV in potassium borate electrolyte compared to bare bismuth vanadate photoanode films. [ABSTRACT FROM AUTHOR]