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The electrocatalytic behavior and anodic performance of Sb-SnO2 and nickel-doped Sb-SnO2 (Ni-Sb-SnO2) in sodium sulfate and sodium chloride electrolytes were compared. Nickel-doping increased the service lifetime by a factor of 9 and decreased the charge transfer resistance of the Sb-SnO2 electrodes by 65%. More importantly, Ni doping improved the electrocatalytic performance of Sb-SnO2 for the remediation of aqueous phenol and the inactivation of E. coli by a factor of more than 600% and ∼20%, respectively. In the sulfate electrolyte, the primary reactive oxygen species (ROS) identified were OH radicals (Faradaic efficiency η = 2.4%) with trace levels of ozone and hydrogen peroxide (η < 0.01%) at Sb-SnO2. In contrast, the primary ROS at Ni-Sb-SnO2 was ozone (η = 9.3%) followed by OH radicals (η = 3.7%). In the chloride electrolyte, the production of hypochlorite (OCl(-)) was higher (η = 0.73%) than that of ozone (η = 0.13%) at Sb-SnO2, whereas the level of ozone (η = 13.6%) was much higher than that of hypochlorite (η = 0.24%) at Ni-Sb-SnO2. Based on the shift of the reactive species, the primary effect of Ni doping is to catalyze the six-electron oxidation of water to ozone and inhibit the competing one or two-electron oxidation of water (generation of OH radicals, hydrogen peroxides, and hypochlorites). A range of electrochemical and surface analyses were performed, and a detailed mechanism was proposed.

The sustainability of conventional water-and energy-associated systems is being examined in terms of water-energy nexus. This study presents a high-efficiency, off-grid solar desalination system for saline water (salinity 10 and g L −1) that accompanies electrocatalytic oxidations of chloride and, consequently, urine via oxidized chlorine species, while concomitantly producing formate from captured CO2. A variable number of desalination cell arrays is placed between a double-layered nanoparticulate titania electrocatalyst (Ti/IrxTa1−xOy/nano-TiO2; denoted as n-TEC) anode and a porous dendrite Bi cathode. A potential bias to the n-TEC and Bi pair initiates the transport of chloride and sodium ions in the saline water to the anode and cathode cells, respectively, at an ion transport efficiency of ~100% and a specific energy consumption of ~1.9 kWh m −3. During the desalination, the n-TEC anode catalyzes the conversion of the transported chloride into reactive chlorine species, which in turn mediate the decomposition of urine in the anode cell. Concurrent with the anodic process, formate is continuously produced at a Faradaic efficiency of >95% from the CO2 captured in the catholyte. When a photovoltaic cell (power conversion efficiency of ~18%) is coupled to the stack device with five desalination cells, the three independent processes synergistically proceed at a maximum overall solar-to-desalination system efficiency ~16% and a maximum solar-toformate chemical energy conversion efficiency of ~7%.

Bifunctional hybrid electrodes capable of generating various reactive oxygen species (ROS) over a wide range of potentials were developed by coupling electrocatalysts and photoelectrocatalysts. To achieve this, Ni-doped Sb-SnO2 (NSS) was deposited on one side of a titanium (Ti) foil while the other side was anodized to grow a TiO2 nanotube array (TNA) for electrochemical ozone generation and photoelectrochemical hydroxyl radical generation, respectively. Surface characterization indicated that NSS and TNA were formed and spatially separated yet electrically connected through the Ti substrate. While each catalyst possessed unique electrochemical properties, the coupling of both catalysts resulted in mixed electrochemical properties that drove electrocatalysis at high potentials and photoelectrocatalysis at low potentials. The performance of the NSS/TNA electrode for phenol decomposition was ∼3 times greater than that of single-layer catalysts and ∼1.5 times greater than the combined catalytic performances of the individual NSS and TNA catalysts. This synergistic effect was attributed partly to the simultaneous generation of hydroxyl radicals and ozone, followed by the production of other ROS. A mechanism for the generation of ROS was discussed.

Objectives:The purpose of this study was to determine the setting time, compressive strength, solubility, and pH of mineral trioxide aggregate (MTA) mixed with glass ionomer cement (GIC) and to compare these properties with those of MTA, GIC, IRM, and SuperEBA. Materials and Methods: Setting time, compressive strength, and solubility were determined according to the ISO 9917 or 6876 method. The pH of the test materials was determined using a pH meter with specified electrode for solid specimen. Results: The setting time of MTA mixed with GIC was significantly shorter than that of MTA. Compressive strength of MTA mixed with GIC was significantly lower than that of other materials at all time points for 7 days. Solubility of 1 : 1 and 2 : 1 specimen from MTA mixed with GIC was significantly higher than that of other materials. Solubility of 1 : 2 specimen was similar to that of MTA. The pH of MTA mixed with GIC was 2-4 immediately after mixing and increased to 5-7 after 1 day. Conclusions: The setting time of MTA mixed with GIC was improved compared with MTA. However, other properties such as compressive strength and pH proved to be inferior to those of MTA. To be clinically feasible, further investigation is necessary to find the proper mixing ratio in order to improve the drawbacks of MTA without impairing the pre-existing advantages and to assess the biocompatibility. [J Kor Acad Cons Dent 2010;35(5):344-352.]