Covalent triazine-based frameworks (CTFs) with a graphene-like layered morphology have been controllably synthesized by the trifluoromethanesulfonic acid-catalyzed nitrile trimerization reactions at room temperature via selecting different monomers. Platinum nanoparticles are well dispersed in CTF-T1, which is ascribed to the synergistic effects of the coordination of triazine moieties and the nanoscale confinement effect of CTFs. CTF-T1 exhibits excellent photocatalytic activity and stability for H2 evolution in the presence of platinum under visible light irradiation (λ ≥ 420 nm). The activity and stability of CTF-T1 are comparable to those of g-C3 N4 . Importantly, as a result of the tailorable electronic and spatial structures of CTFs that can be achieved through the judicial selection of monomers, CTFs not only show great potential as organic semiconductor for photocatalysis but also may provide a molecular-level understanding of the inherent heterogeneous photocatalysis.

using electrocatalysts, the OER will take place at a high overpotential leading to significant losses of the overall efficiency of water splitting. Although RuO 2 and IrO 2 are highly efficient catalysts for the OER, [1b] the exorbitant price and scarcity of Ru and Ir severely restrict their widespread use in electrolyzers.Remarkable progress has been made in developing efficient nonprecious OER electrocatalysts, such as perovskite oxides, [3] transition metal (TM) oxides, [4] (oxy)hydroxides, [5] phosphates, [6] phosphides, [7] nitrides, [8] chalcogenides, [9] and metal-free carbon nanostructures. [10] Recently, cobalt selenide with different polymorphs has attracted considerable attention for use as efficient catalysts to expedite the OER in basic solution [9a-f ] or the HER in acidic solution, [11] most of which were prepared by a two-step method involving either the synthesis of Co-containing precursors followed by a selenization process, [11a-f ] or the synthesis of selenide precursors followed by a cation-exchange process. [9f ] Since the high OER activity expected for pure cobalt selenide remains out of reach, strategies that can enhance the OER activity of cobalt selenide have been explored. For example, composites of CoSe 2 with graphene [9d] or metal oxides [9a,e] were reported, and exhibited OER activity substantially higher than that of pure CoSe 2 . The enhanced OER activity is believed to result from the synergistic interaction between cobalt selenide and graphene/ metal oxides. [9a,d,e] Besides, ultrathin CoSe 2 nanosheets (NSs) and atomic layers were synthesized by delaminating lamellar hybrid CoSe 2 -DETA (DETA = diethylenetriamine) intermediates, with the aim of exposing more low-coordinated catalytically active sites and achieving better structural stability. [9b,c] These NSs and single-unit-cell atomic layers have accomplished substantially improved OER activity compared to both bulk CoSe 2 and CoSe 2 -DETA intermediates, requiring only a low overpotential (η) of 320 mV at 10 mA cm −2 in basic medium and showing a small Tafel slope of 44 mV decade −1 (dec −1 ). [9b] While CoSe 2 is still the most commonly studied polymorph of cobalt selenide, [9a−f,11] nonstoichiometric cobalt selenide (e.g., Co 0.85 Se) has drawn great attention very recently Cobalt selenide has been proposed to be an effective low-cost electrocatalyst toward the oxygen evolution reaction (OER) due to its well-suited electronic configuration. However, pure cobalt selenide has by far still exhibited catalytic activity far below what is expected. Herein, this paper for the first time reports the synthesis of new monoclinic Co 3 Se 4 thin nanowires on cobalt foam (CF) via a facile one-pot hydrothermal process using selenourea. When used to catalyze the OER in basic solution, the conditioned monolithic selfsupported Co 3 Se 4 /CF electrode shows an exceptionally high catalytic current of 397 mA cm −2 at a low overpotential (η) of 320 mV, a small Tafel slope of 44 mV dec −1 , a turnover frequency of 6.44 × 10 −2 ...

A facile method based on microwave-assisted solvothermal process has been developed to synthesize flowerlike MgO precursors, which were then transformed to MgO by simple calcinations. All the chemicals used (magnesium nitrate, urea, and ethanol) were low cost and environmentally benign. The products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution TEM, and N(2) adsorption-desorption methods. These flowerlike MgO nanostructures had high surface area and showed superb adsorption properties for Pb(II) and Cd(II), with maximum capacities of 1980 mg/g and 1500 mg/g, respectively. All these values are significantly higher than those reported on other nanomaterials. A new adsorption mechanism involving solid-liquid interfacial cation exchange between magnesium and lead or cadmium cations was proposed and confirmed.