3-Hydroxythiophenol-Formaldehyde Resin Microspheres Modulated by Sulfhydryl Groups for Highly Efficient Photocatalytic Synthesis of H2 O2.

Resorcinol-formaldehyde (RF) resin represents a promising visible-light responding photocatalyst for oxygen reduction reaction (ORR) toward H2 O2 production. However, its photocatalytic ORR activity toward H2 O2 generation is still unsatisfied for practical application. Herein, 3-hydroxythiophenol-formaldehyde (3-HTPF) resin microspheres synthesized through polycondensation reaction between 3-HTP and formaldehyde at room temperature and subsequent hydrothermal treatment exhibit enhanced photocatalytic ORR activity is reported. The experimental results show that the partial substitution of hydroxy group (─OH) by sulfhydryl one (─SH) through using 3-HTP to replace resorcinol could slow the rates of nucleation and growth of the resin particles and lead to strongly π-stacked architecture in 3-HTPF. The introduction of ─SH group can also improve adsorption ability of 3-HTPF to O2 molecules and enhance ORR catalytic activity of the photocatalysts. Stronger built-in electric field, better adsorption ability to O2 molecules, and increased surface catalytic activity collectively boost photocatalytic activity of 3-HTPF microspheres. As a result, H2 O2 production rate of 2010 µm h-1 is achieved over 3-HTPF microspheres at 273 K, which is 3.4 times larger than that obtained using RF submicrospheres (591 µm h-1 ). The rational substituent group modulation provides a new strategy for designing polymeric photocatalysts at the molecular level toward high-efficiency artificial photosynthesis.

Vertical growth of SnS2 nanobelt arrays on CuSbS2 nanosheets for enhanced photocatalytic reduction of CO2.

Two-dimensional SnS2 nanobelt arrays vertically grown on two-dimensional CuSbS2 nanosheet (2D SnS2⊥2D CuSbS2) heterostructures were synthesized via a facile solution-phase growth route. The resultant SnS2⊥CuSbS2 heterostructures showed enhanced photocatalytic activity for CO2 reduction because of unique structural advantages and the p-n heterojunction with matched energy band alignment.

Highly efficient utilization of light and charge separation over a hematite photoanode achieved through a noncontact photonic crystal film for photoelectrochemical water splitting.

The trade-off problem between light absorption and charge collection under lower band-bending (bias) is extremely difficult to resolve in water splitting on photoelectrodes. Although the use of metallic back-reflectors, antireflection coatings, and textured substrates and light absorbers enable the improvement of light utilization efficiency, these methods still suffer from high cost and complex fabrication process, especially, incompetent separation of photogenerated carriers. Here taking the hematite (α-Fe2O3) photoanode as a model, we report that a noncontact photonic crystal (PC) film composed of silica nanoparticles and ethoxylated trimethylolpropane triacrylate (ETPTA) resin can significantly enhance the photoelectrochemical (PEC) activity of the photoelectrode. Specifically, more than 250 mV cathodic shift in the onset potential and 4 times larger photocurrent at 1.0 V versus a reversible hydrogen electrode (RHE) were achieved over the α-Fe2O3-PC photoanode hybrid system, compared with the pristine α-Fe2O3 photoanode. Our work showed that a PC film not only boosted light absorption of the α-Fe2O3 layer but also improved its charge transfer efficiency under light illumination. These new findings of the synergistic effect will open a new avenue to design high-performance solar energy conversion devices.

Interface Engineering of Mn-Doped ZnSe-Based Core/Shell Nanowires for Tunable Host-Dopant Coupling.

Transition metal ion doped one-dimensional (1-D) nanocrystals (NCs) have advantages of larger absorption cross sections and polarized absorption and emissions in comparison to 0-D NCs. However, direct synthesis of doped 1-D nanorods (NRs) or nanowires (NWs) has proven challenging. In this study, we report the synthesis of 1-D Mn-doped ZnSe NWs using a colloidal hot-injection method and shell passivation for core/shell NWs with tunable optical properties. Experimental results show optical properties of the NWs are controlled by the composition and thickness of the shell lattice. It was found that both the host-Mn energy transfer and Mn-Mn coupling are strongly dependent on the type of alloy at the interface of doped core/shell NWs. For Mn-doped type I ZnSe/ZnS core/shell NWs, the ZnS shell passivation can enhance florescence quantum yield with little effect on the location of the incorporated Mn dopant due to the identical cationic Zn2+ site available for Mn dopants throughout the core/shell NWs. However, for Mn-doped quasi type II ZnSe/CdS NWs and ZnSe/CdS/ZnS core/shell NWs, the cation alloying (Zn1-xCdxS(e)) can lead to metal dopant migration from the core to the alloyed interface and tunable host-dopant energy transfer efficiencies and Mn-Mn coupling. As a result, a tunable dual-band emission can be achieved for the doped NWs with the cation-alloyed interface. The interfacial alloying mediated energy transfer and Mn-Mn coupling provides a method to control the optical properties of the doped 1-D core/shell NWs.

Indented Cu2MoS4 nanosheets with enhanced electrocatalytic and photocatalytic activities realized through edge engineering.

Edges often play a role as active centers for catalytic reactions in some nanomaterials. Therefore it is highly desirable to enhance catalytic activity of a material through modulating the microstructure of the edges. However, the study associated with edge engineering is less investigated and still at its preliminary stage. Here we report that Cu2MoS4 nanosheets with indented edges can be fabricated through a simple chemical etching route at room temperature, using Cu2MoS4 nanosheets with flat ones as sacrifice templates. Taking the electrocatalytic hydrogen evolution reaction (HER), photocatalytic degradation of rhodamine B (RhB) and conversion of benzyl alcohol as examples, the catalytic activity of Cu2MoS4 indented nanosheets (INSs) obtained through edge engineering was comparatively studied with those of Cu2MoS4 flat nanosheets (FNSs) without any modification. The photocatalytic tests revealed that the catalytic active sites of Cu2MoS4 nanosheets were associated with their edges rather than basal planes. Cu2MoS4 INSs were endowed with larger electrochemically active surface area (ECSA), more active edges and better hydrophilicity through the edge engineering. As a result, the as-fabricated Cu2MoS4 INSs exhibited an excellent HER activity with a small Tafel slope of 77 mV dec(-1), which is among the best records for Cu2MoS4 catalysts. The present work demonstrated the validity of adjusting catalytic activity of the material through edge engineering and provided a new strategy for designing and developing highly efficient catalysts.

PEGylated Cu3BiS3 hollow nanospheres as a new photothermal agent for 980 nm-laser-driven photothermochemotherapy and a contrast agent for X-ray computed tomography imaging.

Developing multifunctional near-infrared (NIR) light-driven photothermal agents is in high demand for efficient cancer therapy. Herein, PEGylated Cu3BiS3 hollow nanospheres (HNSs) with an average diameter of 80 nm were synthesized through a facile ethylene glycol-mediated solvothermal route. The obtained PEGylated Cu3BiS3 HNSs exhibited strong NIR optical absorption with a large molar extinction coefficient of 4.1 × 10(9) cm(-1) M(-1) at 980 nm. Under the irradiation of a 980 nm laser with a safe power density of 0.72 W cm(-2), Cu3BiS3 HNSs produced significant photothermal heating with a photothermal transduction efficiency of 27.5%. The Cu3BiS3 HNSs also showed a good antitumoral drug doxorubicin (DOX) loading capacity and pH- and NIR-responsive DOX release behaviors. At a low dosage of 10 µg mL(-1), HeLa cells could be efficiently killed through a synergistic effect of chemo- and photothermo-therapy respectively based on the DOX release and the photothermal effect of Cu3BiS3 HNSs. In addition, Cu3BiS3 HNSs displayed a good X-ray computed tomography (CT) imaging capability. Furthermore, Cu3BiS3 HNSs could be used for efficient in vivo photothermochemotherapy and X-ray CT imaging of mice bearing melanoma skin cancer. This multifunctional theranostic nanomaterial shows potential promise for cancer therapy.

Various bismuth oxyiodide hierarchical architectures: alcohothermal-controlled synthesis, photocatalytic activities, and adsorption capabilities for phosphate in water.

Controllable synthesis of morphology and composition of functional material through a similar method is very necessary to understand the related properties. In this study, we report a facile solvothermal route to synthesize a series of bismuth oxyiodide compounds, including BiOI, Bi7O9I3, and Bi4O5I2 hierarchical microspheres, under relatively mild conditions through only adjusting the types of alcohols. It was found that the viscosity of alcohol played key roles in determining the morphologies and compositions of the final products. UV-visible diffuse-reflectance spectra and theoretic calculations indicated that bismuth oxyiodides with different ratios of Bi:O:I clearly possessed different light absorption and energy band structures. As a result, the as-synthesized BiOI, Bi7O9I3, and Bi4O5I2 hierarchical microspheres displayed morphology- and composition-dependent photocatalytic activities for the degradation of rhodamine B (RhB) and colorless phenol under visible-light irradiation. On the basis of experimental results, the difference of photocatalytic activity of these bismuth oxyiodide compounds was discussed. Furthermore, hierarchical bismuth oxyiodide microspheres were also evaluated as adsorbents for removing phosphate from aqueous solution. The results showed that Bi7O9I3 and Bi4O5I2 hierarchical microspheres had good adsorption capabilities for phosphate in water because of their larger surface areas and hierarchical porous structures.

Controlled synthesis of olive-shaped Bi2S3/BiVO4 microspheres through a limited chemical conversion route and enhanced visible-light-responding photocatalytic activity.

Well-defined olive-shaped Bi(2)S(3)/BiVO(4) microspheres were synthesized through a limited chemical conversion route (LCCR), where olive-shaped BiVO(4) microspheres and thioacetamide (TAA) were used as precursors and sulfur source, respectively. The as-synthesized products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission microscope (HRTEM), X-ray photoelectron spectra (XPS), UV-visible diffuse-reflectance spectroscopy (UV-vis DRS), and photoluminescence (PL) spectra in detail. Compared with pure BiVO(4) microspheres and Bi(2)S(3) nanorods, the Bi(2)S(3)/BiVO(4) products showed obviously enhanced photocatalytic activity for the degradation of rhodamine B (Rh B) in aqueous solution under visible-light irradiation (λ > 400 nm). In addition, the Bi(2)S(3)/BiVO(4) composite microspheres showed good visible-light-driven photocatalytic activity for the degradation of refractory oxytetracycline (OTC) as well. On the basis of UV-vis DRS, the calculated energy band positions, and PL spectra, the mechanism of enhanced photocatalytic activity of Bi(2)S(3)/BiVO(4) was proposed. The present study provides a new strategy to design composite materials with enhanced photocatalytic performance.

Single-crystal NaY(MoO4)2 thin plates with dominant {001} facets for efficient photocatalytic degradation of dyes under visible light irradiation.

Single-crystal NaY(MoO(4))(2) thin plates dominated by high-energy {001} facets were hydrothermally synthesized under relatively mild conditions, free of organic additives, seeds and templates. The as-obtained NaY(MoO(4))(2) thin plates showed an excellent visible-light-responding photocatalytic activity for degradation of dyes in water.

From hollow olive-shaped BiVO4 to n-p core-shell BiVO4@Bi2O3 microspheres: controlled synthesis and enhanced visible-light-responsive photocatalytic properties.

In this study, hollow olive-shaped BiVO(4) and n-p core-shell BiVO(4)@Bi(2)O(3) microspheres were synthesized by a novel sodium bis(2-ethylhexyl)sulfosuccinate (AOT)-assisted mixed solvothermal route and a thermal solution of NaOH etching process under hydrothermal conditions for the first time, respectively. The as-obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy, Brunauer-Emmett-Teller surface area, and UV-vis diffuse-reflectance spectroscopy in detail. The influence of AOT and solvent ratios on the final products was studied. On the basis of SEM observations and XRD analyses of the samples synthesized at different reaction stages, the formation mechanism of hollow olive-shaped BiVO(4) microspheres was proposed. The photocatalytic activities of hollow olive-shaped BiVO(4) and core-shell BiVO(4)@Bi(2)O(3) microspheres were evaluated on the degradation of rhodamine B under visible-light irradiation (λ > 400 nm). The results indicated that core-shell BiVO(4)@Bi(2)O(3) exhibited much higher photocatalytic activities than pure olive-shaped BiVO(4). The mechanism of enhanced photocatalytic activity of core-shell BiVO(4)@Bi(2)O(3) microspheres was discussed on the basis of the calculated energy band positions as well. The present study provides a new strategy to enhancing the photocatalytic activity of visible-light-responsive Bi-based photocatalysts by p-n heterojunction.

An unusual zinc substrate-induced self-construction route to various hierarchical architectures of hydrated tungsten oxide.

A novel active zinc substrate-induced sequential self-construction method is presented for the fabrication of hydrated WO(3) hierarchical octahedrons, flakes, lanterns, and arresting sandwiched double-layer nanorods arrays architectures for the first time. Photocatalytic activity and gas sensing properties of the as-obtained various WO(3).0.33H(2)O architectures were studied as well.

Bisurfactant-controlled synthesis of three-dimensional YBO3/Eu3+ architectures with tunable wettability.

Three-dimensional (3D) architectures of YBO(3)/Eu(3+) with different morphologies such as nest-like, rose-like, cruller-like, and flower-like, were hydrothermally synthesized by simply adjusting the ratios of surfactant polyethylene glycol-6000 (PEG-6000) to octadecylamine (ODA). These 3D architectures were all self-assembled by nanoflakes. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL) spectra were used to characterize the morphology and structures of the samples. PEG-6000, ODA, and the ODA/PEG ratio played important roles in the formation process of various architectures. Rose-like architecture was chosen as a candidate, and the formation mechanism of the architecture was proposed on the basis of XRD analysis and SEM observation of the products at different reaction periods of time. As-synthesized samples displayed strong emission located at 591, 610, and 615 nm. Water contact angle measurements indicated that the films fabricated by the samples obtained under the different ratios of PEG-6000/ODA could exhibit tunable wettability ranging from superhydrophilicity to superhydrophobicity. This kind of one-pot bisurfactant-controlled hydrothermal synthesis method reported here provides a new strategy to realize the surfaces of functional materials with tunable wettability.