| Autor: |
Oyetade OA; Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States., Wang Y; Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States., He S; Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States., Margavio HRM; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States., Bottum SR; Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States., Rooney CL; Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.; Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States., Wang H; Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States.; Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States., Donley CL; Chapel Hill Analytical and Nanofabrication Laboratory (CHANL), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States., Parsons GN; Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States., Cohen-Karni T; Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States., Cahoon JF; Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States. |
| Abstrakt: |
Carbon electrodes are ideal for electrochemistry with molecular catalysts, exhibiting facile charge transfer and good stability. Yet for solar-driven catalysis with semiconductor light absorbers, stable semiconductor/carbon interfaces can be difficult to achieve, and carbon's high optical extinction means it can only be used in ultrathin layers. Here, we demonstrate a plasma-enhanced chemical vapor deposition process that achieves well-controlled deposition of out-of-plane "fuzzy" graphene (FG) on thermally oxidized Si substrates. The resulting Si|FG interfaces possess a silicon oxycarbide (SiOC) interfacial layer, implying covalent bonding between Si and the FG film that is consistent with the mechanical robustness observed from the films. The FG layer is uniform and tunable in thickness and optical transparency by deposition time. Using p -type Si|FG substrates, noncovalent immobilization of cobalt phthalocyanine (CoPc) molecular catalysts was employed for the photoelectrochemical reduction of CO 2 in aqueous solution. The Si|FG|CoPc photocathodes exhibited good catalytic activity, yielding a current density of ∼1 mA/cm 2 , Faradaic efficiency for CO of ∼70% (balance H 2 ), and stable photocurrent for at least 30 h at -1.5 V vs Ag/AgCl under 1-sun illumination. The results suggest that plasma-deposited FG is a robust carbon electrode for molecular catalysts and suitable for further development of aqueous-stable Si photocathodes for CO 2 reduction. |
