Production of Liquid Solar Fuels and Their Use in Fuel Cells Shunichi Fukuzumi  Joule  Volume 1, Issue 4, Pages 689-738 (December 2017) DOI: 10.1016/j.joule.2017.07.007 Copyright © 2017 Terms and Conditions

Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 1 Photoelectrocatalytic Cell for CO2 Reduction Schematic illustration of the photoelectrochemical reduction of CO2 with a two-electrode configuration with no electrical bias, comprising an InP/[RuCP] photocathode and a TiO2/Pt photoanode.144 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 2 Photocatalytic Synthesis of Formate on CuFeO2/CuO (Coupled to a Pt Foil) After being used for the first 7 days, an as-synthesized photocatalyst (fresh) was annealed at 923 K for 3 hr in the presence of atmospheric air (e.g., identical to the synthesis conditions) and recycled for CO2 photoconversion (denoted as first week recycled).147 This recycling was repeated four times and hence the single photocatalyst sample was used for 5 weeks in total for CO2 conversion under continuous irradiation with an AM 1.5G light. Changes in Ecell are also shown. Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 3 I-V and I-P Curves at 30°C for Two Sets of DFAFCs Using Pd–B/C and Pd/C as the Anode Catalysts, Respectively The flowing rate of 3 M formic acid was 200 mL min−1 and the flowing rate of O2 was 500 mL min−1. Note: in the polarization measurement of the fuel cell, the open-circuit duration for refueling 3 M formic acid was ca. 300 s.165 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 4 Time Course of Production of Methanol by CO2 Hydrogenation Plots of concentrations of methanol, ethyl formate, and formic acid (TON) with respect to time for CO2 hydrogenation to methanol under the catalysis of [Co(acac)3]/Triphos/HNTf2 in THF (8 mL) and EtOH (3 mL) with H2 (70 bar) and CO2 (20 bar) at 100°C.222 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 5 Time Courses of Formation Formic Acid and Methanol by CO2 Hydrogenation with the Ir(III)-OH2 Catalyst (15) P(13CO2) = 20 bar, P(H2) = 60 bar, 1 = 15.9 μmol, m(H2O) = 2.0 g.223 Formic acid concentrations obtained at 60°C (blue squares), at 25°C (gray squares), and in 2.5 M H2SO4 at 70°C (green squares). Methanol (green circles) concentrations were detected in the presence of H2SO4 at 70°C, under these conditions. The dashed curve indicates an observable decrease in formic acid concentration due to continuous methanol formation. Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 6 Time Course of CH3OH and O2 Production from the Photocatalytic CO2 Reduction System Conditions: BiVO4 (0.2 g), 1.0 M NaOH solution (100 mL), and full-spectrum irradiation of a Xe lamp.227 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 7 Cell Performance of an Ammonia SOFC I-V curves of an anode-supported cell at 550–650°C: Ni/BCY25||BCY10|SSC fueled with 45.0% H2, 1.0% H2O, 54.0% N2, and 42.9% NH3, 1.4% H2O, 55.7% N2; cathode gas, O2.281 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 8 Catalytic Reduction of N2 to NH3 Catalytic formation of ammonia by the reduction of N2 with larger amounts of CoCp∗2 as a reductant and [LutH]OTf as a proton source in the presence of dimolybdenum catalysts in toluene.332 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 9 Catalytic Reduction of N2 to N2H4 and NH3 Catalytic formation of hydrazine and ammonia by the reduction of N2 with larger amounts of CoCp∗2 as a reductant and Ph2NH2OTf as a proton source in the presence of dimolybdenum catalysts in toluene.333 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 10 DHFC Performance of Two Different NiZn Anode Catalysts Conditions: catalyst loading 2 mg cm−2 (anode), 1 mg cm−2 (cathode); 80°C, hydrazine hydrate flow rate = 2 mL min−1 (20 wt %), air flow rate = 500 cm3 min−1.360 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 11 Daihatsu Fuel Cell Electric Vehicle with an Alkaline Membrane Fuel Cell Stack, Shown in Blue, Using Hydrazine Hydrate as Fuel The vehicle was presented at the Tokyo Motor Show in December 2013.360 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 12 Effects of Metal Nitrates on Photocatalytic Production of H2O2 Photocatalytic H2O2 production in the absence and presence of metal ions with Lewis acidity under irradiation of [RuII(Me2phen)3]2+ (20 μM) with visible light (λ > 420 nm) for 1 hr in the presence of Ir(OH)3 (3.0 mg) and M(NO3)n (Mn+ = Sc3+, Y3+, Yb3+, Lu3+, Zn2+, Mg2+, and Ca2+, 100 mM) in O2-saturated H2O (3.0 mL, [O2] = 1.2 mM).407 The pH values of the solutions were adjusted to 2.8 by adding HNO3. Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 13 Photocatalytic Production of H2O2 with NiFe2O4 (A) Time courses of H2O2 production under visible-light irradiation (λ > 420 nm) of [RuII(Me2phen)3]2+ (200 μM) in the presence of Sc3+ (100 mM) and NiFe2O4 (0.17 g L−1) with diameters of 1,300 nm (black circle), 120 nm (blue square), and 91 nm (red triangle) in O2-saturated H2O (3.0 mL, [O2] = 1.2 mM).416 (B) Time course of H2O2 production in the presence of NiFe2O4 (0.17 g L−1) and Sc3+ (100 mM) under visible-light irradiation (λ > 420 nm) of [RuII(Me2phen)3]2+ (200 μM) in O2-saturated H2O (3.0 mL, [O2] = 1.2 mM).416 [RuII(Me2phen)3]2+ was added twice to the reaction suspension at 50 hr and 100 hr during photoirradiation. The amount of [RuII(Me2phen)3]2+ added to the reaction suspension each time at 50 hr and 100 hr was calculated in terms of the concentration increasing from 200 μM. Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 14 Photoelectrocatalytic Cell for Production of H2O2 from Water or Seawater A two-compartment cell for photocatalytic production of H2O2 from water and O2 using an m-WO3/FTO photoanode and a CoII(Ch)/CP cathode, separated by Nafion membrane in water or seawater under simulated 1 sun (AM 1.5G) illumination.429 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 15 Photocatalytic Production of H2O2 from Water, Seawater, and Water with NaCl Time courses of H2O2 production with a WO3/FTO photoanode and CoII(Ch)/CP cathode in pH 1.3 water (red circle), in pH 1.3 seawater (blue circle), and in an NaCl aqueous solution (pH 1.3) (blue square) under simulated 1 sun (AM 1.5G) illumination.429 Time course of H2O2 production in the absence of CoII(Ch) on carbon paper under simulated 1 sun (AM 1.5G) illumination in pH 1.3 water is shown as black circles. Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 16 A One-Compartment H2O2 Fuel Cell A one-compartment H2O2 fuel cell with iron phthalocyanine or porphyrin complex as a cathode and Ni mesh as an anode in an acidic solution, where H2O2 is used as both fuel and oxidant (GC, glassy carbon electrode).440 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Figure 17 Cell Performance of H2O2 Fuel Cells I-V and I-P curves of one-compartment H2O2 fuel cells with a Ni mesh anode and carbon cloth electrode modified with [FeII(H2O)2]3[CoIII(CN)6]2 in an aqueous solution containing 0.30 M H2O2, 0.12 M Sc(NO3)3, and 1.0 M NaCl at 25°C.444 Currents and powers were normalized by the geometric surface area of the electrodes. Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 1 Catalytic Cycles of Interconversion between Hydrogen and Formic Acid See Maenaka et al.94 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 2 Catalytic Cycles of Hydrogen Production from Paraformaldehyde with an Ir(III)-OH Complex (3) See Suenobu et al.174 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 3 Formation of the Amido Complex by Dehydrochlorination of a Ru(II)-Hydride PNP Complex with Base and (P = PiPr2) See Alberico et al.205 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 4 Formation of the Amido Complex and the Reaction of the Amido Complex with Methanol and the Equilibrium between the Products (P = PiPr2) See Alberico et al.205 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 5 Proposed Mechanism for the Hydrogen Production from a Methanol-Water Solution Catalyzed by an Ir(III)-Hydroxo Complex See Fujita et al.175 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 6 Base-free Hydrogen Production from Aqueous Methanol with Ru(II)-Hydride PNP Complexes (A0 and A1) See Monney et al.212 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 7 Synthesis of Fe(II)-Hydride Pincer Complexes See Alberico et al.213 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 8 Synthesis of Fe(II)-Hydride Pincer Complexes See Bielinski et al.214 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 9 Catalysts of Hydrogenation of CO2 to Methanol See Kothandaraman et al.220 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 10 Sequence for CO2 Capture and In Situ Hydrogenation to CH3OH Using a Polyamine See Kothandaraman et al.220 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 11 Photocatalytic Production of H2O2 from H2O and O2 under Photoirradiation of [RuII(Me2phen)3]2+ in the Presence of [CoIIICp*(bpy) (OH2)]2+ in H2O Containing Sc (NO3)3 See Kato et al.407 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions

Scheme 12 Photocatalytic Cycle of Visible-Light-Driven Water Oxidation by O2 to Produce H2O2 with a Composite Photocatalyst, NiII[RuII(CN)4(bpy)] See Aratani et al.418 Joule 2017 1, 689-738DOI: (10.1016/j.joule.2017.07.007) Copyright © 2017 Terms and Conditions