This README.txt file was generated on [20181210] by [KatarzynaSokol] ------------------- GENERAL INFORMATION ------------------- 1. Photoreduction of CO2 with a Formate Dehydrogenase Driven by Photosystem II Using a Semi-artificial Z‑Scheme Architecture 2. Authors: Katarzyna P. Sokol, William E. Robinson, Ana R. Oliveira, Julien Warnan, Marc M. Nowaczyk, Adrian Ruff, Inês A. C. Pereira, and Erwin Reisner 3. Date of data collection: 201806-201811 4. Geographic location of data collection: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K. 5. Information about funding sources that supported the collection of the data: This work was supported by an ERC Consolidator Grant “MatEnSAP” (682833 to E.R.), the U.K. Engineering and Physical Sciences Research Council (EP/L015978/1 and EP/G037221/1, nanoDTC to W.E.R., and a DTA studentship to K.P.S.), the Chris-tian Doppler Research Association (Austrian Federal Ministry for Digital and Economic Affairs and the National Foundation for Re-search, Technology and Development), the OMV group (to E.R. and J.W.), the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft (to A.R. and M.M.N.), the European Union's Horizon 2020 MSCA ITN-EJD 764920 PHOTOBIOCAT (to M.M.N.), Fundação para a Ciência e Tecno-logia (Portugal) fellowship SFRH/BD/116515/2016 (to A.R.O.), grant PTDC/BIA-MIC/2723/2014 and R&D units UID/Multi/04551/2013 (Green-IT) and LISBOA-01-0145-FEDER-007660 (MostMicro) cofunded by FCT/MCTES and FEDER funds through COMPETE2020/POCI and European Un-ion’s Horizon 2020 research and innovation programme (grant agreement No 810856). Research project data has originated from: Photoelectrochemistry of Photosystem II Integrated into Tailor-Made 3D Electrodes (Ref 1504802), U.K. Engineering and Physical Sciences Research Council (EPSRC) DTA Award. 6. Publication: Journal of the American Chemical Society, 2018, 140 (48), pp 16418–16422 DOI: 10.1021/jacs.8b10247 -------------------------- SHARING/ACCESS INFORMATION -------------------------- Recommended citation for the data: Additional data related to this publication are available at the University of Cambridge data repository (https://doi.org/10.17863/CAM.32922). --------------------- ABSTRACT --------------------- Abstract (directly reproduced from the above-named paper and authors): Solar-driven coupling of water oxidation with CO2 reduction sus-tains life on our planet and is of high priority to contemporary ener-gy research. Here, we report a photoelectrochemical tandem device, which performs photocatalytic CO2 reduction to formate. We em-ploy a semi-artificial design, which wires a W-dependent formate dehydrogenase (FDH) cathode to a photoanode containing the pho-tosynthetic water oxidation enzyme, photosystem II, via a synthetic dye with complementary light absorption. From a biological per-spective, the system achieves a metabolically-inaccessible pathway of light-driven CO2 fixation to formate. From a synthetic point of view, it represents a proof-of-principle system utilizing precious-metal-free catalysts for selective CO2 to formate conversion using water as an electron donor. This hybrid platform demonstrates the translatability and versatility of coupling abiotic and biotic compo-nents to create challenging models for solar fuel and chemical synthesis. --------------------- FIGURES --------------------- Figure 1: (Panel A) Schematic representation of the semi-artificial photosynthetic tan-dem PEC cell coupling CO2 reduction to water oxidation. A blend of POs and PSII adsorbed on a dpp-sensitized photoanode (IO-TiO2|dpp|POsPSII) is wired to an IO-TiO2|FDH cathode (species size not drawn to scale). (Panel B) Energy level diagram showing the electron-transfer pathway between PSII, the redox polymer (POs), the dye (dpp), the conduc-tion band (CB) of IO-TiO2 electrodes, four [Fe4S4] clusters and the [WSe]-active site in FDH. All potentials are reported vs. SHE at pH 6.5. Figure 2: PFV scans (v = 5 mV s−1) of IO-TiO2 (black trace) and IO-TiO2|FDH (red traces, arrow indicates scan order). Inset: CPE at Eapp = −0.6 V vs. SHE. Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. A three-electrode configuration employed a two-compartment cell with Ag/AgCl (saturated KCl) reference and Pt mesh counter electrodes. Figure 3: Characterization of two-electrode PEC cell consisting of IO-TiO2|FDH cathode wired to IO-TiO2|dpp|POsPSII tandem pho-toanode. (Panel A) Representative stepped-voltage chronoamperometry (0.1 V voltage steps with 30 s dark and 30 s light cycles) of the fully assembled PEC cell (red trace). Control experiments in absence of PSII (green and black trace) and without FDH (blue and black trace) are also shown. Applied voltage (Uapp) values are shown on top of the traces. (Panel B) CPE (Uapp = 0.3 V) of the two-electrode PSII-FDH system (red trace) and a similar system in the absence of FDH (blue trace). Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmos-phere CO2, pH = 6.5, T = 25 °C, continuous stirring. Simulated solar light source: AM 1.5G filter; Ee = 100 mW cm−2; λ > 420 nm. Figure S1: Schematic representation of the dye-sensitized IO-TiO2|dpp|POsPSII photoanode wired to IO-TiO2|FDH cathode (species size not drawn to scale). Abbreviations: Mn4Ca, oxygen-evolving complex (OEC); TyrZ, tyrosine; P680, pigment/primary electron donor; PheoD1/PheoD2, pheophytin; QA/QB, plastoquinones; [Fe4S4], iron-sulfur clusters; [WSe], FDH active site; Eg, bang gap energy; EF, Fermi level; all potentials reported vs. SHE at pH 6.5. Scheme adopted from [Sokol, K. P.; Robinson, W. E.; Warnan, J.; Kornienko, N.; Nowaczyk, M. M.; Ruff, A.; Zhang, J. Z.; Reisner, E. Bias-Free Photoelectrochemical Water Splitting with Photosystem II on a Dye-Sensitised Photoanode Wired to Hydrogenase. Nat. Energy 2018, 3, 944–951] Figure S2: PFV scan (scan rate = 5 mV s−1) of the IO-TiO2|FDH cathode after 2 h electrolysis with continuous stirring at Eapp = −0.6 V vs. SHE (see red trace in Figure 2 inset) showing the activity retention for CO2 reduction to formate (HCO2−). Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. A three-electrode configuration employed a working electrode and a Ag/AgCl (saturated KCl) reference and Pt mesh counter electrode, respectively. Figure S3: Three-electrode characterization of the IO-TiO2|dpp|POs-PSII photoanode. Stepped-potential chronoamperometry (0.1 V potential steps with 30 s dark and 10 s light cycles) for the determination of onset potential (Eonset) and limiting photocurrent for IO-TiO2|dpp|POs-PSII photoanode. Eapp values (shown on top of the lines) are reported vs. SHE. Short irradiation times were used to minimize PSII photodegradation. Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. Simulated solar light source: AM 1.5G filter; Ee = 100 mW cm−2; λ > 420 nm. A three-electrode configuration employed a working electrode and a Ag/AgCl (saturated KCl) reference and Pt mesh counter electrode, respectively. Figure S4: Photocurrent density as a function of applied voltage (Uapp) (sampled pulse voltammetry) based on stepped-voltage chronoamperometry measurements determined in Figure 3a (0.1 V voltage steps with 30 s dark and 30 s light cycles) for the two-electrode PEC cell consisting of IO-TiO2|FDH cathode wired to IO-TiO2|dpp|POsPSII tandem photoanode. Steady-state J values were taken at the end of illumination and baseline-corrected for background dark current. The fully assembled PEC cell (red trace) and control experiments in absence of PSII (green and black trace) and without FDH (blue and black trace) are shown. Error bars correspond to the standard deviation (N = 3). Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. Simulated solar light source: AM 1.5G filter; Ee = 100 mW cm−2; λ > 420 nm. Figure S5: Two-electrode system characterization of the IO-TiO2|FDH cathode wired to the IO-TiO2|dpp|POs-PSII photoanode (data reproduced from the Figure S4). Photocurrent density as a function of applied bias voltage (Uapp) (−0.2 to 0.1 V) based on stepped-voltage (ΔUapp = 0.1 V) chronoamperometry measurements determined in Figure 3a, indicating close to bias-free capabilities of the device to drive the coupled reactions. Values of J were taken at the end of illumination (baseline-corrected for background dark current). Error bars correspond to the sample standard deviation (N = 3). Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. Simulated solar light source: AM 1.5G filter; Ee = 100 mW cm−2; λ > 420 nm. Figure S6: Stepped-potential chronoamperometry (0.1 V voltage steps with 30 s dark and 60 s light cycles) of the two-electrode IO-TiO2|dpp|POs-PSII || IO-TiO2 cell. Applied voltage (Uapp) values are shown on top of the lines. Spikes during dark phases are due to the change in applied Uapp. Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. Simulated solar light source: AM 1.5G filter; Ee = 100 mW cm−2; λ > 420 nm. Figure S7: Controlled-potential electrolysis at Uapp = 0.6 V of the two-electrode tandem system: IO-TiO2|FDH (or enzyme-free IO-TiO2) cathode wired to the IO-TiO2|dpp|POsPSII photoanode. Formate (n[HCO2−] = 0.209 μmol cm−2, ηF = 95%) produced at the IO-TiO2|FDH cathode (red trace) after continuous 1 h illumination was quantified by IC analysis. The control experiment in absence of FDH (black trace) is also shown (no formate detected). Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. Simulated solar light source: AM 1.5G filter; Ee = 100 mW cm−2; λ > 420 nm. Figure S8: Controlled-potential electrolysis at Uapp = 0.3 V of the two-electrode tandem system. Photocurrent density as a function of time plotted for three independent replicates (red, blue and magenta traces), indicating the reproducibility of the system. Formate (n[HCO2−] = 0.185 ± 0.017 μmol cm−2, ηF = 70 ± 9%; N = 3) produced at the cathode after continuous 1 h illumination was quantified by IC analysis. The series of control experiments in absence of FDH (black, green and light green traces) are also shown. Conditions: CO2/NaHCO3 (100 mM), KCl (50 mM), one atmosphere CO2, pH = 6.5, T = 25 °C, continuous stirring. Simulated solar light source: AM 1.5G filter; Ee = 100 mW cm−2; λ > 420 nm. --------------------- DATA & FILE OVERVIEW --------------------- Name: OpenData_FDH-tandem 1. File List A. Filename: 01_3-electrode_CV Short description: Three-electrode Cyclic voltammetry (raw data .IDS format, .ASCII format, data analysis using Origin Graph .OPJ format) B. Filename: 02_2-electrode_Chronoamp Short description: Two-electrode Chronoamperometry (raw data in .IDS format and .ASCII format, data analysis using Origin Graph .OPJ format and Microsoft Excel Worksheet .XLSX format) C. Filename: 03_Electrolysis Short description: Three-electrode and two-electrode electrolysis (raw data in .IDS format and .ASCII format, data analysis using Origin Graph .OPJ format and Microsoft Excel Worksheet .XLSX format) D. Filename: 04_Product_quantification Short description: Gas Chromatography (raw data in .LOG format, data analysis using Origin Graph .OPJ format and Microsoft Excel Worksheet .XLSX format) and Ionic Chromatography data (raw data in .TXT format, data analysis using Origin Graph .OPJ format and Microsoft Excel Worksheet .XLSX format) -------------------------- METHODOLOGICAL INFORMATION -------------------------- 1. Description of methods used for collection/generation of data: The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/jacs.8b10247. Materials and experimental methods for the electrode preparation, electrochemistry measurements (PFV, CPE, and PEC), and product analysis, including Figures S1−S8: https://pubs.acs.org/doi/suppl/10.1021/jacs.8b10247/suppl_file/ja8b10247_si_001.pdf 2. Research and data collection methods: electrochemistry and photoelectrochemistry (cyclic voltammetry, chronoamperometry, electrolysis), ion and gas chromatography 3. Software-specific information needed to interpret the data: Microsoft Office Excel, Origin 4. People involved with sample collection, processing, analysis: Katarzyna P. Sokol, William E. Robinson 5. Keywords: semi-artificial photosynthesis, enzymes, photosystem II, formate dehydrogenase, photoelectrochemistry, photoelectrochemical cell, tandem system, solar energy, solar-driven, carbon dioxide reduction, carbon fixation, formate, Calvin cycle