Graphene oxide/TiO(2) composites were prepared by using TiCl(3) and graphene oxide as reactants. The concentration of graphene oxide in starting solution played an important role in photoelectronic and photocatalytic performance of graphene oxide/TiO(2) composites. Either a p-type or n-type semiconductor was formed by graphene oxide in graphene oxide/TiO(2) composites. These semiconductors could be excited by visible light with wavelengths longer than 510 nm and acted as sensitizer in graphene oxide/TiO(2) composites. Visible-light driven photocatalytic performance of graphene oxide/TiO(2) composites in degradation of methyl orange was also studied. Crystalline quality and chemical states of carbon elements from graphene oxide in graphene oxide/TiO(2) composites depended on the concentration of graphene oxide in the starting solution. This study shows a possible way to fabricate graphene oxide/semiconductor composites with different properties by using a tunable semiconductor conductivity type of graphene oxide.

Co3O4/BiVO4 composite photocatalyst with a p-n heterojunction semiconductor structure has been synthesized by the impregnation method. The physical and photophysical properties of the composite photocatalyst have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transimission electron microscopy (TEM), BET surface area, and UV-visible diffuse reflectance spectra. Co is present as p-type Co3O4 and disperses on the surface of n-type BiVO4 to constitute a heterojunction composite. The photocatalyst exhibits enhanced photocatalytic activity for phenol degradation under visible light irradiation. The highest efficiency is observed when calcined at 300 degrees C with 0.8 wt % cobalt content. On the basis of the calculated energy band positions and PL spectra, the mechanism of enhanced photocatalytic activity has been discussed.

Electroreduction of CO2 to liquid fuels such as ethanol and n‐propanol, powered by renewable electricity, offers a promising strategy for controlling the global carbon balance and addressing the need for the storage of intermittent renewable energy. In this work, we discovered that the composite composed of nitrogen‐doped graphene quantum dots (NGQ) on CuO‐derived Cu nanorods (NGQ/Cu‐nr) was an outstanding electrocatalyst for the reduction of CO2 to ethanol and n‐propanol. The Faradaic efficiency (FE) of C2+ alcohols could reach 52.4 % with a total current density of 282.1 mA cm−2. This is the highest FE for C2+ alcohols with a commercial current density to date. Control experiments and DFT studies show that the NGQ/Cu‐nr could provide dual catalytic active sites and could stabilize the CH2CHO intermediate to enhance the FE of alcohols significantly through further carbon protonation. The NGQ and Cu‐nr had excellent synergistic effects for accelerating the reduction of CO2 to alcohols.

Electroreduction of CO2 to CO powered by renewable electricity is a possible alternative to synthesizing CO from fossil fuel. However, it is very hard to achieve high current density at high faradaic efficiency (FE). Here, the first use of N,P‐co‐doped carbon aerogels (NPCA) to boost CO2 reduction to CO is presented. The FE of CO could reach 99.1 % with a partial current density of −143.6 mA cm−2, which is one of the highest current densities to date. NPCA has higher electrochemical active area and overall electronic conductivity than that of N‐ or P‐doped carbon aerogels, which favors electron transfer from CO2 to its radical anion or other key intermediates. By control experiments and theoretical calculations, it is found that the pyridinic N was very active for CO2 reduction to CO, and co‐doping of P with N hinder the hydrogen evolution reaction (HER) significantly, and thus the both current density and FE are very high.

Catalysts H 2000Efficient Photocatalytic Degradation of Phenol over Co3O4/BiVO4 Composite under Visible Light Irradiation. -The title composite photocatalyst is synthesized by the impregnation method from aqueous solutions of Co(NO3)2 and BiVO4 and characterized by XRD, XPS, TEM, BET surface area measurements, and UV/VIS diffuse reflectance spectroscopy. Co3O4/BiVO4 exhibits enhanced photocatalytic activity for phenol degradation under visible light irradiation. The highest efficiency is observed after calcination at 300°C with 0.8 wt% Co content. The mechanism of enhanced photocatalytic activity is discussed on the basis of the calculated energy band positions and photoluminescence spectra. The composite photocatalyst is promising for water purification applications for its good precipitation performance and stability. -(LONG, M.; CAI*, W.; CAI, J.; ZHOU, B.; CHAI, X.; WU, Y.; J.

Electrocatalytic reduction of CO2 into multicarbon (C2+) products powered by renewable electricity offers one promising way for CO2 utilization and promotes the storage of renewable energy under the ambient environment....

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In this study, we found that poly(vinyl phenol)/polybenzoxazine (PVPh/PBZ) copolymers feature low surface energies when they possess a minimal number of intermolecular hydrogen-bonding interactions. For example, PVPh/PBZ = 30/70 exhibits an extremely low surface energy of 16.8 mJ/m2 after thermal curingeven lower than that of poly(tetrafluoroethylene) (22.0 mJ/m2)based on calculations performed using a two-liquid geometric method. Infrared spectroscopic analyses indicated that a decrease in the degree of intermolecular hydrogen bonding in the PVPh/PBZ copolymers resulted in a lower surface free energy. An increase in the intermolecular hydrogen bonding did, however, enhance the thermal properties, namely, the glass-transition temperature, the thermal decomposition temperature, and the char yield. The manipulation of intermolecular hydrogen-bonding interactions is a unique and simple approach toward preparing low-surface-energy materials without the need to employ fluoropolymers or silicones.