La2Sn2O7 (LSO) micro/nanospheres, synthesized by a hydrothermal method, exhibited photocatalytic performance for CO2 reduction. The evolution rate of the main reduction products (CH4 and CO) was 0.20 and 0.10 μmol h−1, respectively. Loading of Au co-catalyst over La2Sn2O7 efficiently enhanced the photocatalytic activity of CO2 reduction. The highest photocatalytic efficiency was obtained over 1 wt% Au/La2Sn2O7 with an apparent quantum yield (AQY) of 2.54%. Characterization techniques including SEM, TEM, XRD, XPS, DRS, PL, and electrochemical analysis were applied and the physicochemical properties of La2Sn2O7 and Au/La2Sn2O7 samples are discussed. A possible mechanism of photocatalytic CO2 reduction over Au/La2Sn2O7 is proposed.

Urchin-like LaPO4 hollow spheres were successfully synthesized by a facile solution route using citric acid (CA) as a structure-directing agent. The size of the three-dimensional (3D) hollow spheres was tuned by changing the concentration of CA. The formation mechanism of the 3D LaPO4 hollow spheres was revealed by studying the time-dependent morphology evolution process. Importantly, compared with monodispersed one-dimensional (1D) LaPO4 nanorods, the 3D LaPO4 hollow spheres self-assembled from nanorods showed a 6.8-fold enhancement in photocatalytic activity for CO2 reduction, which is attributed to the synergistic effect of their hierarchical hollow structure, higher light-harvesting capacity, and faster electron transfer. Our findings provide not only a simple, facile method for the synthesis of hierarchical hollow micro/nanoarchitectures but also an efficient route for enhancing the photocatalytic performance.

Here, we show for the first time that the photocatalytic activity of covalent triazine-based frameworks (CTFs) can be efficiently improved using a facile sulfur-doping approach. The sulfur-doped CTFs show superior photocatalytic activity and stability in hydrogen evolution from water under visible light irradiation over pristine CTFs and g-C3N4. The significantly improved catalytic efficiency was attributed to sulfur-doping in the frameworks, which results in enhanced adsorption of visible light, reduced recombination of free charge carriers, and rapid separation and transportation of photogenerated electron–holes.

The photocatalytic CO2 reduction over LaPO4 was significantly enhanced by simply introducing CoCl2 into the aqueous medium. The introduced CoCl2 functioned as a co-catalyst accelerating photogenerated hole transfer, by the reversible redox couple CoIII–Cl/CoII–Cl, effectively suppressing the recombination of photogenerated charges.

A facile approach for the heterogenization of transition metal catalysts using non-covalent interactions in hollow click-based porous organic polymers (H-CPPs) is presented. A catalytically active cationic species, [Ru(bpy)3]2+ (bpy = 2,2’-bipyridyl), was immobilized in H-CPPs via electrostatic interactions. The intrinsic properties of [Ru(bpy)3]2+ were well retained. The resulting Rucontaining hollow polymers exhibited excellent catalytic activity, enhanced stability, and good recyclability when used for the oxidative hydroxylation of 4-methoxyphenylboronic acid to 4-methoxyphenol under visible-light irradiation. The attractive catalytic performance mainly resulted from efficient mass transfer and the maintenance of the chemical properties of the cationic Ru complex in the H-CPPs.

•H2 evolution activity of BiPO4 and BiPO4/RGO was first reported.•The incorporation of RGO into BiPO4 results in a significant enhancement in the photocatalytic activity.•Three different methods were used to prepare BiPO4/RGO, and hydrothermal method is the most effective one.Nanocomposites of BiPO4 and reduced graphene oxide (BiPO4/RGO) synthesized by hydrothermal method, hydrazine reduction, and UV-assisted photoreduction method were studied as photocatalysts for hydrogen evolution from ethanol aqueous solution under irradiation. The incorporation of RGO into BiPO4 significantly enhanced the photocatalytic activity for H2 evolution, and the photocatalytic activity increases in the order of BiPO4/RGO-hydrothermal > BiPO4/RGO-photoreduction > BiPO4/RGO-hydrazine. The optimum proportion of GO is 2 wt% for all the samples prepared by different methods. The rate of H2 production calculated for BiPO4/RGO-hydrothermal (with 2 wt% GO) nanocomposite was about 306 μmol/h/g, which was almost 2 times as high as that for bare BiPO4. The XRD, Raman and XPS characterization suggested that the original GO was successfully reduced to RGO. The more intimate contact between BiPO4 and RGO, the higher photocurrent responses and the higher reduction degree of RGO was consistent with the higher photocatalytic performance.

A novel orthorhombic LaCO3OH photocatalyst is synthesized by a facile hydrothermal method. The prepared LaCO3OH sample exhibits high photocatalytic activity for hydrogen evolution from aqueous methanol solutions under UV light irradiation, which is about 3 times higher than that of anatase TiO2. The Mott–Schottky plot shows the VCB of the prepared LaCO3OH of −0.87 V vs. RHE at pH 7. Theoretical calculations of the electronic structures for LaCO3OH reveal that the top of the valence band (VB) and the bottom of the conduction band (CB) are mainly composed of O 2p and La 4f states, respectively. The superior photocatalytic performance of LaCO3OH could be ascribed predominantly to the high reduction potential of photoinduced electrons. A possible mechanism for the hydrogen evolution over LaCO3OH is proposed. This work highlights the potential application of lanthanum-based materials in the field of energy conversion.

LaOF samples were synthesized by a facile hydrothermal method followed by a subsequent heat treatment. Its performance for photocatalytic hydrogen production under UV light irradiation was first reported. Loading of the Pt cocatalyst over LaOF was observed to efficiently enhance the photocatalytic H2 production activity. With techniques such as XPS, DRS, flat potential measurement and PL, the physicochemical properties of the LaOF samples were discussed.Download full-size imageHighlights► The LaOF is synthesized by a hydrothermal method with subsequent heat-treatment. ► The LaOF exhibits photocatalytic activity for H2 evolution from CH3OH/H2O solutdion. ► The Pt-loading on the LaOF is beneficial for the photocatalytic H2 evolution.

A novel orthorhombic LaCO3OH photocatalyst is synthesized by a facile hydrothermal method. The prepared LaCO3OH sample exhibits high photocatalytic activity for hydrogen evolution from aqueous methanol solutions under UV light irradiation, which is about 3 times higher than that of anatase TiO2. The Mott–Schottky plot shows the VCB of the prepared LaCO3OH of −0.87 V vs. RHE at pH 7. Theoretical calculations of the electronic structures for LaCO3OH reveal that the top of the valence band (VB) and the bottom of the conduction band (CB) are mainly composed of O 2p and La 4f states, respectively. The superior photocatalytic performance of LaCO3OH could be ascribed predominantly to the high reduction potential of photoinduced electrons. A possible mechanism for the hydrogen evolution over LaCO3OH is proposed. This work highlights the potential application of lanthanum-based materials in the field of energy conversion.

Here, we show for the first time that the photocatalytic activity of covalent triazine-based frameworks (CTFs) can be efficiently improved using a facile sulfur-doping approach. The sulfur-doped CTFs show superior photocatalytic activity and stability in hydrogen evolution from water under visible light irradiation over pristine CTFs and g-C3N4. The significantly improved catalytic efficiency was attributed to sulfur-doping in the frameworks, which results in enhanced adsorption of visible light, reduced recombination of free charge carriers, and rapid separation and transportation of photogenerated electron–holes.