Hybrid Molecular/Materials Approach to Semiconductor Catalysis
“Solar Fuels” is a multidisciplinary area of research that involves using the energy provided by sunlight to carry out chemical reactions. Nature has crafted its own version of this process, utilizing photosystem II (PSII) to execute the light-driven oxidation of water. The system consists of two parts: a light-absorber (Mg-porphyrin) and a catalyst (Mn-O cubane).
One important challenge in chemical research today is to simulate some version of ‘Artificial Photosynthesis’ by interfacing light absorbing materials (Si, GaP, CdTe) with molecular, metallic or materials catalysts in novel ways that preserve the essential function of both components.
The goal of our group is to investigate new ways to build hybrid molecular/materials interfaces to integrate and stabilize each component. The resulting passivated and functionalized semiconductor could be used to generate fuels (e.g. dihydrogen, alcohols) directly from sunlight in an integrated device. For example, we recently showed that H2 photogeneration can be achieved using a combination of materials and molecular chemistry as shown below in a p-Si(111)|diOMePh|AZO|TiO2|PNP-Ni-PNP photocathode.
Related techniques include organic synthesis, inorganic synthesis, atomic layer deposition (ALD), X-ray photoelectron spectroscopy (XPS), electrochemistry and photoelectrochemistry.
H. J. Kim*, K. L. Kearney*, L. H. Le, Z. J. Haber, A. A. Rockett and M. J. Rose. Charge-Transfer through Ultrathin Film TiO2 on n-Si(111) Photoelectrodes: Experimental and Theoretical Investigation of Electric Field-Enhanced Transport with a Non-Aqueous Redox Couple. J. Phys. Chem. C 2016, 25697-25708. DOI: 10.1021/acs.jpcc.6b08096
O. M. Williams, J. Shi and M. J. Rose. Photoelectrochemical Study of p-GaP(100)|ZnO|AuNP Devices: Strategies for Enhanced Electron Transfer and Aqueous Catalysis. Chem. Commun. 2016, 9145-9148. DOI: 10.1039/C6CC00703A
D. R. Redman, H. J. Kim, K. J. Stevenson and M. J. Rose. Photo-Assisted Electrodeposition of MoSx from Ionic Liquids on Organic-Functionalized Silicon Photoelectrodes for H2 Generation. J. Mater. Chem. A. 2016, 7027-7035. DOI: 10.1039/c5ta09684g
H. J. Kim, J. Seo and M. J. Rose. H2 Photogeneration Using a Phosphonate-Anchored Ni-PNP Catalyst on a Band-Edge-Modified p-Si(111)|AZO Construct. ACS Appl. Mater. Interfaces, 2016, 8, 1061-1066. DOI: 10.1021/acsami.5b09902
F. Li, V. M. Basile and M. J. Rose. Electron Transfer through Surface-Grown, Ferrocene-Capped Oligophenylene Molecular Wires (5-50 A) on n-Si(111) Photoelectrodes. Langmuir, 2015, 31, 7712-7716. DOI: 10.1021/acs.langmuir.5b02121
J. Seo, R. T. Pekarek and M. J. Rose. Photoelectrochemical Operation of a Surface-Bound, Nickel-Phosphine H2 Evolution Catalyst on p-Si(111): A Molecular Semiconductor|Catalyst Construct. Chem. Commun. 2015, 51, 13264-13267. DOI: 10.1039/c5cc02802g
H. J. Kim, K. L. Kearney. L. Le, R. T. Pekarek and M. J. Rose. Platinum-Enhanced Electron Transfer through Ultra-Thin Film Aluminum Oxide (Al2O3) on Si(111) Photoelectrodes. ACS Appl. Mat. Intfc. 2015, 8572-8584. Link
J. Seo, H. J. Kim, R. T. Pekarek and M. J. Rose. Hybrid Organic/Inorganic Band-Edge Modulation of p-Si(111) Photoelectrodes: Effects of R, Metal Oxide, and Pt on H2 Generation. J. Am. Chem. Soc. 2015, 137, 3173-3176. Link
F. Li, V. M. Basile, R. T. Pekarek and M. J. Rose. Steric Spacing of Molecular Linkers on Passivated Si(111) Photoelectrodes. ACS Appl. Mater. Interfaces. 2014, 6, 20557-20568. Link