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Register a new userCO2 dissociation activated through electron attachment on reduced rutile TiO2(110)-1x1 surface
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Converting CO$_2$ to useful compounds through the solar photocatalytic reduction has been one of the most promising strategies for artificial carbon recycling. The highly relevant photocatalytic substrate for CO$_2$ conversion has been the popular TiO$_2$ surfaces. However, the lack of accurate fundamental parameters that determine the CO$_2$ reduction on TiO$_2$ has limited our ability to control these complicated photocatalysis processes. We have systematically studied the reduction of CO2 at specific sites of the rutile TiO$_2$(110)-1x1 surface using scanning tunneling microscopy at 80 K. The dissociation of CO2 molecules is found to be activated by one electron attachment process and its energy threshold, corresponding to the CO$_2^{dot-}$/CO$_2$ redox potential, is unambiguously determined to be 2.3 eV higher than the onset of the TiO$_2$ conduction band. The dissociation rate as a function of electron injection energy is also provided. Such information can be used as practical guidelines for the design of effective catalysts for CO$_2$ photoreduction.
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Present study investigates the photoabsorption properties of single crystal rutile TiO2 (110) surfaces after they have been implanted with low fluence of Cobalt ions. The surfaces, after implantation, demonstrate fabrication of nanostructures and anisotropic nano-ripple patterns. Creation of oxygen vacancies (Ti3+ states) as well as band gap modification for these samples is also observed. Results presented here demonstrate that fabrication of self organized nanostructures and development of oxygen vacancies, upon cobalt implantation, promote the enhancement of photoabsorbance in both UV (2 times) and visible (5 times) regimes. These investigations on nanostructured TiO2 surfaces can be important for photo- catalysis.
Photocatalytic water splitting reaction on TiO2 surface is one of the fundamental issues that bears significant implication in hydrogen energy technology and has been extensively studied. However, the existence of the very first reaction step, the direct photo-dissociation of water, has been disregarded. Here, we provide unambiguously experimental evidence to demonstrate that adsorbed water molecules on reduced rutile TiO2(110)-1times1 surface can be dissociated under UV irradiation using low temperature scanning tunneling microscopy. It is identified that a water molecule at fivefold coordinated Ti (Ti5c) site can be photocatalytically dissociated, resulting in a hydroxyl at Ti5c and another hydroxyl at bridge oxygen row. Our findings reveal a missing link in the photocatalytic water splitting reaction chain, which greatly contribute to the detailed understanding of underlying mechanism.
We report experimental results on three-dimensional momentum imaging measurements of anions generated via dissociative electron attachment to gaseous formamide. From the momentum images, we analyze the angular and kinetic energy distributions for NH$_2^{-}$, O$^{-}$, and H$^{-}$ fragments and discuss the possible electron attachment and dissociation mechanisms for multiple resonances for two ranges of incident electron energies, from 5.3~eV to 6.8~eV, and from 10.0~eV to 11.5~eV. {it Ab initio} theoretical results for the angular distributions of the NH$_2^{-}$ anion for $sim$6~eV incident electrons, when compared with the experimental results, strongly suggest that one of the two resonances producing this fragment is a $^2$A$$ Feshbach resonance.
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We present experimental results for dissociative electron attachment to acetylene near the 3 eV $^2Pi_g$ resonance. In particular, we use an ion-momentum imaging technique to investigate the dissociation channel leading to C$_2$H$^-$ fragments. From our measured ion-momentum results we extract fragment kinetic energy and angular distributions. We directly observe a significant dissociation bending dynamic associated with the formation of the transitory negative ion. In modeling this bending dynamic with emph{ab initio} electronic structure and fixed-nuclei scattering calculations we obtain good agreement with the experiment.
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