Pt/MnO2 Nanoflowers Anchored to Boron Nitride Aerogels for Highly Efficient Enrichment and Catalytic Oxidation of Formaldehyde at Room Temperature.

The catalytic room temperature oxidation of formaldehyde (HCHO) is widely considered as a viable method for the abatement of indoor toxic HCHO pollution. Herein, Pt/MnO2 nanoflowers anchored to boron nitride aerogels (Pt/MnO2 -BN) were fabricated for the catalytic room temperature oxidation of HCHO. The three-dimensional Pt/MnO2 -BN aerogels demonstrated superior catalytic activity as a result of the improved diffusion of the reactant molecules within the porous structure. Furthermore, the porous aerogels displayed excellent HCHO adsorption capacities, which promote a rapid HCHO gas-phase concentration reduction and a subsequent complete oxidation of the adsorbed HCHO. The combined adsorption and oxidation properties of the Pt/MnO2 -BN aerogels enhance the oxidative removal of HCHO. The optimized Pt/MnO2 -BN demonstrated excellent catalytic activity toward HCHO (200 ppm) at room temperature, achieving a 96 % formaldehyde conversion after 50 min.

Spatially Separating Redox Centers on Z-Scheme ZnIn2 S4 /BiVO4 Hierarchical Heterostructure for Highly Efficient Photocatalytic Hydrogen Evolution.

Photocatalysis technology using solar energy for hydrogen (H2 ) production still faces great challenges to design and synthesize highly efficient photocatalysts, which should realize the precise regulation of reactive sites, rapid migration of photoinduced carriers and strong visible light harvest. Here, a facile hierarchical Z-scheme system with ZnIn2 S4 /BiVO4 heterojunction is proposed, which can precisely regulate redox centers at the ZnIn2 S4 /BiVO4 hetero-interface by accelerating the separation and migration of photoinduced charges, and then enhance the oxidation and reduction ability of holes and electrons, respectively. Therefore, the ZnIn2 S4 /BiVO4 heterojunction exhibits excellent photocatalytic performance with a much higher H2 -evolution rate of 5.944 mmol g-1 h-1 , which is about five times higher than that of pure ZnIn2 S4 . Moreover, this heterojunction shows good stability and recycle ability, providing a promising photocatalyst for efficient H2 production and a new strategy for the manufacture of remarkable photocatalytic materials.

Construction of Hierarchical Hollow Co9 S8 /ZnIn2 S4 Tubular Heterostructures for Highly Efficient Solar Energy Conversion and Environmental Remediation.

Visible-light-responsive hierarchical Co9 S8 /ZnIn2 S4 tubular heterostructures are fabricated by growing 2D ZnIn2 S4 nanosheets on 1D hollow Co9 S8 nanotubes. This design combines two photoresponsive sulfide semiconductors in a stable heterojunction with a hierarchical hollow tubular structure, improving visible-light absorption, yielding a large surface area, exposing sufficient catalytically active sites, and promoting the separation and migration of photogenerated charges. The hierarchical nanotubes exhibit excellent photocatalytic H2 evolution and CrVI reduction efficiency. Under visible-light illumination, the optimized Co9 S8 /ZnIn2 S4 heterostructure provides a remarkable H2 generation rate of 9039 µmol h-1 g-1 without the use of any co-catalysts and CrVI is completely reduced in 45 min. The Co9 S8 /ZnIn2 S4 heterostructure is stable after multiple photocatalytic cycles.

Hierarchical Titanium Dioxide Nanowire/Metal-Organic Framework/Carbon Nanofiber Membranes for Highly Efficient Photocatalytic Degradation of Hydrogen Sulfide.

Photocatalysis is an efficient approach to degrade hydrogen sulfide (H2 S) and titanium dioxide (TiO2 ) is commonly used as a catalyst for H2 S degradation. However, the low separation rate of photoinduced carriers and low gas adsorption ability of TiO2 limit its H2 S photocatalytic decomposition rate. In this paper, single-crystalline TiO2 nanowires are assembled on one-dimensional carbon nanofibers (CNFs) and a tunable metal-organic framework (MOF) coating is fabricated on the surface of the TiO2 nanowires using a versatile step-by-step self-assembly strategy. The excellent photocatalytic properties of the resulting membrane originate from the ability of the CNFs to rapidly transport charge carriers and the high and regenerable H2 S adsorption ability of the MOF. The photocatalytic mechanism of the as-prepared material was also discussed. Therefore, this work provides a promising method to improve the photocatalytic performance of H2 S degradation.

Visible-light-driven amino acids production from biomass-based feedstocks over ultrathin CdS nanosheets.

Chemical synthesis of amino acids from renewable sources is an alternative route to the current processes based on fermentation. Here, we report visible-light-driven amination of biomass-derived α-hydroxyl acids and glucose into amino acids using NH3 at 50 °C. Ultrathin CdS nanosheets are identified as an efficient and stable catalyst, exhibiting an order of magnitude higher activity towards alanine production from lactic acid compared to commercial CdS as well as CdS nanoobjects bearing other morphologies. Its unique catalytic property is attributed mainly to the preferential formation of oxygen-centered radicals to promote α-hydroxyl acids conversion to α-keto acids, and partially to the poor H2 evolution which is an undesired side reaction. Encouragingly, a number of amino acids are prepared using the current protocol, and one-pot photocatalytic conversion of glucose to alanine is also achieved. This work offers an effective catalytic system for amino acid synthesis from biomass feedstocks under mild conditions.

Hierarchical core-shell heterostructures of ZnIn2S4 nanosheets on electrospun In2O3 nanofibers with highly enhanced photocatalytic activity.

Well-designed heterostructure semiconductor photocatalysts can improve the activity of photocatalytic reactions. In this work, we constructed a series of hierarchical ZnIn2S4/In2O3 heterostructures by growing ultrathin two-dimensional ZnIn2S4 nanosheets onto one-dimensional In2O3 electrospun nanofibers and used them as photocatalysts for the efficient photoreduction of toxic Cr(VI). This structural design increased the specific surface area, promoted the separation of photogenerated electrons and holes, and provided more active sites for the catalytic reactions. Under visible light irradiation, the optimized ZnIn2S4/In2O3 photocatalyst showed the highest photocatalytic performance with 100% reduction efficiency for Cr(VI) (50 mg/L) within 90 min, which is much higher than pure In2O3 and ZnIn2S4. Additionally, the recycling tests and X-ray diffraction (XRD) characterization indicated the stability of the ZnIn2S4/In2O3 photocatalyst, making it a promising candidate for environmental remediation applications. Finally, the two active species (e- and ·O2-) participating in the photoreduction process were determined via trapping experiments and electron spin resonance (ESR) spectroscopy. Finally, a possible mechanism for the ZnIn2S4/In2O3 heterojunction photocatalytic system was carefully determined.

SnS2/SnO2 heterostructured nanosheet arrays grown on carbon cloth for efficient photocatalytic reduction of Cr(VI).

Nowadays, among the many heavy metal pollutants, hexavalent chromium (Cr(VI)) seriously threatens ecological systems and human health due to its high solubility, acute toxicity and potential carcinogenicity in wastewater. Meanwhile, semiconductor photocatalytic reduction is continuously gaining increasing significant research attention in the treatment of Cr(VI). Hence, we report an efficient preparation method for SnS2/SnO2 composites on carbon cloth (CC), for efficient photocatalytic reduction of aqueous Cr(VI). The morphology, composition, surface elements and optical properties of CC@SnS2/SnO2 composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy. It was found that carbon cloth (CC) could be effectively used as a catalyst support in the obtained SnS2/SnO2 composites. In addition, the CC@SnS2 calcined 30 min exhibited the best efficiency for photocatalytic reduction of aqueous Cr(VI), which can be attributed to the formation of a heterostructure and the effective separation of photogenerated electrons (e-) and holes (h+). It was also found that acidic conditions are more favorable for the photocatalytic reduction of aqueous Cr(VI) due to the presence of abundant H+. The photocatalytic mechanism of as-prepared composites is also discussed in detail.