Photocatalytic Reductions using p-GaP Photoelectrode and NAD+/NADH Analogs

POSTER

Abstract

This project investigates photocatalytic reduction of protons using NAD$^{\mathrm{+}}$/NADH analogs attached to the surface of appropriate photocathode (p-GaP). The NAD$^{\mathrm{+}}$ analogs are first photo-chemically reduced to NADH analogs, then the hydride transfer from NADH analogs to protons leads to the H$_{\mathrm{2}}$ evolution. The light harvesting is achieved by NAD$^{\mathrm{+}}$ analogs (red photons) and by p-GaP (blue photons). Our initial study of the photoreduction step involved six NAD$^{\mathrm{+}}$ analog dyes, only two of which showed successful photosensitization of GaP. Subsequent femtosecond pump-probe measurements indicated that the two successful dyes are the ones with sufficiently long excited-state lifetimes (\textgreater 600 ps). The hydricities of model NADH analogs were evaluated using computational and experimental methods, and the results showed that most of the NADH analogs are excellent hydride donors. However, the proton reduction using NADH analogs occurred only in the presence of Pd as a catalyst. The results indicated that NADH analogs exhibit high thermodynamic hydricities, but sluggish hydride transfer kinetics.

Authors

  • Stefan Ilic

    Bowling Green State University

  • Mikhail Zamkov

    University of Notre Dame, University of Toledo, Case Western Reserve University, John Carroll University, Bowling Green State Univ, Materials Science and Technology Division, Oak Ridge National Laboratory, Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Ohio University, Shanghai Jiao Tong University, Department of Chemistry and Biochemistry, University of Toledo, Department of Chemical Engineering, University of Toledo, Wuhan University, Southeast University, Physics and Astronomy and Center for Photochemical Science, Bowling Green State University, Physics and Astronomy, University of Toledo, Air Force Research Laboratory, Physics and Astronomy, Bowling Green State University, Purdue University, Student/Supervisor, Student, None, University of Michigan, Dearborn, Clemson University, Michigan State University, Bowling Green State University, Physics Dep, Cleveland State University, Physical Therapy Program, Central Michigan State University

  • Mikhail Zamkov

    University of Notre Dame, University of Toledo, Case Western Reserve University, John Carroll University, Bowling Green State Univ, Materials Science and Technology Division, Oak Ridge National Laboratory, Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Ohio University, Shanghai Jiao Tong University, Department of Chemistry and Biochemistry, University of Toledo, Department of Chemical Engineering, University of Toledo, Wuhan University, Southeast University, Physics and Astronomy and Center for Photochemical Science, Bowling Green State University, Physics and Astronomy, University of Toledo, Air Force Research Laboratory, Physics and Astronomy, Bowling Green State University, Purdue University, Student/Supervisor, Student, None, University of Michigan, Dearborn, Clemson University, Michigan State University, Bowling Green State University, Physics Dep, Cleveland State University, Physical Therapy Program, Central Michigan State University

  • Mikhail Zamkov

    University of Notre Dame, University of Toledo, Case Western Reserve University, John Carroll University, Bowling Green State Univ, Materials Science and Technology Division, Oak Ridge National Laboratory, Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Ohio University, Shanghai Jiao Tong University, Department of Chemistry and Biochemistry, University of Toledo, Department of Chemical Engineering, University of Toledo, Wuhan University, Southeast University, Physics and Astronomy and Center for Photochemical Science, Bowling Green State University, Physics and Astronomy, University of Toledo, Air Force Research Laboratory, Physics and Astronomy, Bowling Green State University, Purdue University, Student/Supervisor, Student, None, University of Michigan, Dearborn, Clemson University, Michigan State University, Bowling Green State University, Physics Dep, Cleveland State University, Physical Therapy Program, Central Michigan State University