The contribution of methanol (CH 3 OH) sacrificing reagent to the photocatalytic evolution of H 2 from aqueous solutions has been studied by tracing the reaction of D 2 O over a Cu/S-TiO 2 catalyst under UV illumination. Use of D 2 O/ CH 3 OH produced higher formation rates of HD and D 2 than that of H 2 . The low H 2 formation rates indicate that the direct reaction of CH 3 OH with photogenerated holes does not proceed to an appreciable extent in the presence of high concentrations of D 2 O. The role of CH 3 OH in accelerating hydrogen formation can be attributed to its ability to produce an electron donor, injecting its electrons to the conduction band.

The rate-determining step of ethanol photocatalytic oxidation was identified to be the adsorption of O(2) by an infrared (IR) spectroscopy coupled with mass spectrometry method. Dosing O(2) during reaction showed that adsorption of O(2) controls the accumulation of photogenerated electrons and the formation of acetate (CH(3)COO(-)(ad)), acyl species (CH(3)CO(ad)), acetaldehyde (CH(3)CHO(ad)), CO(2), and H(2)O. Accumulation of CH(3)COO(-)(ad) on the TiO(2) surface slowed down the conversion of ethanol to CO(2) and H(2)O. Removal of CH(3)COO(-)(ad) from the TiO(2) surface holds the key to accelerating the rate of ethanol photocatalytic oxidation. This study bridges the gap between results of nanosecond and millisecond transient absorption studies and those of minute scale photocatalytic oxidation studies.

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The direct use of sulfur-containing coke to generate electricity has been studied by a transient approach that involves feeding a batch of coke samples to a NiÀyttria-stabilized zirconia (YSZ) anode solid oxide fuel cell operating at 750 °C in flowing He, measuring the fuel cell performance, and monitoring the concentration of the exhaust gases with a mass spectrometer (MS) and a gas chromatograph (GC). Feeding coke to the fuel cell produced current densities as high as 261 mA/cm 2 at a load of 0.56 V with the concomitant evolution of CO 2 , giving an energy efficiency (i.e., the ratio of the electric energy produced to the enthalpy of consumed fuel) of 52.9%, nearly 3 times higher than the efficiency resulting from feeding H 2 fuel. The volumetric three-phase boundary (TPB) length available at the NiÀYSZ anode for electrochemical oxidation of H 2 was estimated to be 4.1 Â 10 12 m/m 3 , which is 3 orders of magnitude larger than the TPB length available for oxidation of carbon at the anode surface in direct contact with the solid fuel. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) mapping of the NiÀYSZ anode after the experiments in coke showed the absence of sulfur compounds, indicating that the sulfur-containing coke did not transfer any sulfur species that could cause poisoning to the anode surface. The fuel cell performance and energy efficiency results support the feasibility of direct power generation from coke in a NiÀYSZ anode solid oxide fuel cell.