Photocatalytic CO 2 conversion for hydrocarbon fuel production has been known as one of the most promising strategies for achieving carbon neutrality. Yet, its conversion efficiency remains unsatisfactory mainly due to its severe charge-transfer resistance and slow charge kinetics. Herein, a tunable interfacial charge transfer on an oxygen-vacancies-modified bismuth molybdate nanoflower assembled by 2D nanosheets (BMOVs) and 2D bismuthene composite (Bi/BMOVs) is demonstrated for photocatalytic CO 2 conversion. Specifically, the meticulous design of the Ohmic contact formed between BMOVs and bismuthene can allow the modulation of the interfacial charge-transfer resistance. According to density functional theory (DFT) simulations, it is ascertained that such exceptional charge kinetics is attributed to the tunable built-in electric field (IEF) of the Ohmic contact. As such, the photocatalytic CO 2 reduction performance of the optimized Bi/BMOVs (CO and CH 4 productions rate of 169.93 and 4.65 μmol g −1 h −1 , respectively) is ca. 10 times higher than that of the pristine BMO (CO and CH 4 production rates of 16.06 and 0.51 μmol g −1 h −1 , respectively). The tunable interfacial resistance of the Ohmic contact reported in this work can shed some important light on the design of highly efficient photocatalysts for both energy and environmental applications.

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Hierarchically porous nanocrystalline CaTiO 3 , SrTiO 3, and BaTiO 3 ceramics have been produced by impregnating corresponding alkaline-earth metal ions into preformed macroporous TiO 2 monoliths in a solution containing urea, followed by calcination. The macroporous TiO 2 had been obtained via the sol-gel process accompanied by phase separation utilizing a chelating agent, ethyl acetylacetonate (EtAcAc), together with mineral salt and ammonium chloride, to decrease the reactivity of titanium alkoxide. Formations of CaCO 3 , SrCO 3 , and BaCO 3 on the surface of TiO 2 monoliths are promoted by CO 2 generated by the concurrent two processes during impregnation; hydrolysis, and decarbonation of the chelating agent EtAcAc, and hydrolysis of urea at 60°C. The latter also raises pH of the impregnating solution which further promotes the mineralization of the carbonate salts. Calcination of the resultant monolithic composite of metal carbonate/TiO 2 allows the crystallization of metal titanate. The addition of urea to the impregnating solution is found to be an effective strategy for the formation of perovskite monoliths by the impregnation process. This study provides a versatile approach to the preparation of hierarchically porous titania-based perovskites. P. Paranthaman-contributing editor

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This study investigates the dissolution behavior as well as the surface biomineralization in simulated body fluid (SBF) of a paste composed of glycerol (gly) and a bioactive glass in the system CaO-MgO-SiO2-Na2O-P2O5-CaF2 (BG). The synthesis of the bioactive glass in an alumina crucible has been shown to significantly affect its bioactivity due to the incorporation of aluminum (ca. 1.3–1.4 wt %) into the glass network. Thus, the kinetics of the hydroxyapatite (HA) mineralization on the glass prepared in the alumina crucible was found to be slower than that reported for the same glass composition prepared in a Pt crucible. It is considered that the synthesis conditions lead to the incorporation of small amount of aluminum into the BG network and thus delay the HA mineralization. Interestingly, the BG-gly paste was shown to have significantly higher bioactivity than that of the as-prepared BG. Structural analysis of the paste indicate that glycerol chemically interacts with the glass surface and strongly alter the glass network architecture, thus generating a more depolymerized network, as well as an increased amount of silanol groups at the surface of the glass. In particular, BG-gly paste features early intermediate calcite precipitation during immersion in SBF, followed by hydroxyapatite formation after ca. seven days of SBF exposure; whereas the HA mineralization seems to be suppressed in BG, probably a consequence of the incorporation of aluminum into the glass network. The results obtained within the present study reveal the positive effect of using pastes based on bioactive glasses and organic carriers (here alcohols) which may be of interest not only due to their advantageous visco-elastic properties, but also due to the possibility of enhancing the glass bioactivity upon surface interactions with the organic carrier.