An effective, template-free synthesis methodology has been developed for preparing mesoporous nitrogen-doped SrTiO 3 (meso-STON) using glycine as both a nitrogen source and a mesopore creator. The N-doping, large surface area and developed porosity endow meso-STON with excellent activity in visible-light-responsive photodegradation of organic dyes.The exceptional electro-optical properties and physicochemical stability of the perovskite SrTiO 3 (STO) give rise to its attractive performance in photocatalytic applications of solar power, including photocatalytic degradation of organic pollutants, water splitting and photoreduction of CO 2 .1-3 However, the intrinsic large bandgap energy (E g = 3.2 eV) of SrTiO 3 allows only the utilization of UV light, encompassing approximately 5.0% energy of the sunlight. 4 A variety of transition metals (TM) have been doped into a STO's crystal matrix in efforts to tune its electronic bandgap for harvesting visible light. 5,6Unfortunately, TM-doping can also bring about either phase impurity or fast recombination of photogenerated charge carriers. Nonmetal-doping represents another effective strategy to realize visible-light response.7-9 Indeed, it was found that N-doped SrTiO 3 (SrTiO 3Àx N x , STON) exhibited excellent photoreactivity and stability under visible-light irradiation. 10Mesoporous-structured photocatalysts are highly desirable in photocatalysis since their large specific surface area (SSA) and mesoporous channels greatly facilitate adsorption, diffusion and surface reaction of the reactants.11 STO perovskite belongs to the cubic crystal system, and typically has low SSA and poor porosity. Moreover, the porosity of STO could be further destroyed by the known processes of nitriding STO to STON. 5,12Although mesoporous STO has been prepared via templatedirected synthesis using various soft (e.g. surfactant or polymer 13 ) and hard (e.g. inorganic salts 14 ) templates, the synthesis of mesoporous STON has rarely been achieved.Here we report a novel, template-free synthesis methodology to prepare mesoporous STON using glycine as both a nitrogen source and a mesopore creator. Aqueous solution of glycine and Sr(NO 3 ) 2 was dropped into ethanol solution of titanium butoxide under stirring, followed by solvent evaporation and subsequent calcinations at 550 1C for 2 hours. The obtained STON was characterized by XRD, TEM, FTIR, UV-vis, and XPS techniques and used for the photodegradation of three refractory organic dyes under visible-light irradiation.Only a strong single peak appears in the small angle XRD pattern (Fig. 1) of the STON sample, suggesting that it possesses disordered wormlike mesopores. 15 The TEM image in Fig. 2A nicely confirms such mesoporosity. The HRTEM image inserted in Fig. 2A reveals that the walls of the mesopores are comprised of single crystal perovskite STON. The labelled lattice distances are consistent with those of (100) and (110) diffractions obtained from XRD tests (Fig. S1, ESIw). In contrast, the STO sample presents poor mesoporous featu...

The thermal stability of hollow gold nanoparticles has been studied by molecular dynamics (MD) simulations. On the basis of the MD simulation results, the hollow nanoparticles have been classified into three categories, namely, stable, half-stable, and unstable systems. The stability of hollow nanoparticles strongly depends on the wall thickness and the aspect ratio, defined as the outer radius over the wall thickness. These features can be further presented in a two-dimensional phase space according to a large number of simulations. By using this stability diagram, the collapsing mechanism has been proposed.

In this work, we describe three simple modifications to carbon electrodes that were found to improve the detection of an exemplar neurotransmitter (dopamine) in the presence of physiological interferents (ascorbic acid and/or uric acid). First, the electro-oxidation of ascorbic acid, as a pretreatment, at boron-doped diamond electrode (BDE) interfaces is studied. This treatment did suppress the detection of ascorbic acid oxidation signal, but only in a manner suitable for single-use detection of high concentrations of dopamine (i.e., > 1 μM). Second, the hydrogenation of BDE by electrochemical cathodic treatment and plasma hydrogenation was investigated. Large cathodic, applied potentials (i.e., > - 5 V) and hydrogen plasma pretreatment of BDE lead to the partial and complete oxidization of ascorbic acid before dopamine, respectively. The consequence at hydrogen-plasma treated BDE is the complete electrochemical separation of these two species without any typical catalytic reactions between the analytes. Third, the modification of glassy carbon electrodes with carbon black nanoparticles is explored. This modification enables the simultaneous detection of ascorbic acid, dopamine and uric acid, significantly enhancing the sensitivity of dopamine. Dopamine was best detected using the unconventional route of detecting 5,6-dihydroxyindole, which is made possible by use of carbon-black nanoparticles. The potential of all three studied modifications to be of electroanalytical use is highlighted throughout this work.