A unique approach for the synthesis of nonstoichiometric, mesoporous molybdenum oxide (MoO 3-x ) with nanosized crystalline walls by using a soft template (PEO-b -PS) synthesis method is introduced. The as-synthesized mesoporous MoO 3-x is very active and stable (durability > 12 h) for the electrochemical hydrogen evolution reaction (HER) under both acidic and alkaline conditions. The intrinsic MoO 3 serves as an HER electrocatalyst without the assistance of carbon materials, noble metals, or MoS 2 materials. The results from transmission electron microscopy and N 2 sorption techniques show that the as-synthesized mesoporous MoO 3-x has large accessible pores (20-40 nm), which are able to facilitate mass transport and charge transfer during HER. In terms of X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed oxidation, and diffusive refl ectance UV-vis spectroscopy, the mesoporous MoO 3-x exhibits mixed oxidation states (Mo 5+ , Mo 6+ ) and an oxygen-defi cient structure. The as-synthesized MoO 3-x only requires a low overpotential (≈0.14 V) to achieve a 10 mA cm −2 current density in 0.1 M KOH and the Tafel slope is as low as 56 mV dec −1 . Density functional theory calculations demonstrate a change of electronic structure and the possible reaction pathway of HER. Oxygen vacancies and mesoporosity serve as key factors for excellent performance.

CuO is an important transition metal oxide with a narrow bandgap (E g ) 1.2 eV). CuO has been used as a catalyst, a gas sensor, in anode materials for Li ion batteries. CuO has also been used to prepare high temperature superconductors and magnetoresistance materials. In this paper, CuO with urchin-like morphologies has been synthesized via a simple reflux method. The reflux method has advantages over other solution-based techniques, such as ease of operation, safety, and high yield (95%). XRD results showed pure tenorite CuO was produced. FE-SEM exhibited an urchin-like morphology of CuO, which is composed of aggregates of nanosized strips. HR-TEM showed that the strips were single crystals with the lattice fringe of 2.3 Å, which corresponds to (111). DSC and TGA results suggested that as-synthesized CuO had high thermal stability. Time-dependent experiments were conducted to illustrate the evolution of the urchin-like morphology and crystal phase formation of CuO. The effects of copper sources and precipitators on the phase and morphology of the products were studied. As-synthesized CuO showed much better catalytic performance, increased yield (from 64.3% to 89.5%) for olefin epoxidation than commercial CuO and CuO prepared by thermal decomposition of copper hydroxide.

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We report a preparation method for visible light responsive Carbon Quantum Dots (CQDs) embedded in mesoporous TiO 2 materials. The as-prepared mesoporous TiO 2 (meso-Ti-450) material is a member of the recently designed University of Connecticut (UCT) mesoporous materials family. The UCT materials were synthesized based on sol-gel chemistry. The nanoparticles are randomly packed in inverse surfactant micelles and mesopores are formed by interconnected intraparticles. To achieve full usage of the visible region of sunlight (> 400 nm), CQDs were introduced without destroying the mesopores. The photocatalytic performance of the CQDs/meso-Ti-450 was investigated by the degradation of methylene blue. Due to the up-conversion property and electron withdrawing property of CQDs, the photocatalytic activity of the composite material was largely enhanced under visible light irradiation. The highest photocatalytic activity was achieved by 5% CQDs/meso-Ti-450 in an hour. Compared to commercial P25, which is capable of removing 10% methylene blue (MB) under visible light conditions, the 5% CQDs/meso-Ti-450 can mostly remove MB (98%) under the same conditions. To date, the usage of mesoporous titanium oxide and carbon material composites for dye degradation under visible light has not been reported.

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