Photocatalytic Water Splitting and Carbon Dioxide Reduction

Durable Solar-Powered Systems with Ni-Catalysts for Conversion of CO2 or CO to CH4

“…Solar fuel research has gained substantial attention given the abundance of solar energy that hits the Earth’s surface. − In this context, light-driven CO 2 reduction has shown increasing promise toward producing both fuel precursors, such as CO for use in Fischer–Tropsch chemistry, and viable fuels such as methanol and methane. ,, The conversion of solar energy into chemical energy is appealing because it can provide long-term energy storage in a convenient form that is compatible with existing infrastructure. Catalysts driving this process should ideally be based on inexpensive metals and operate in the presence of water to enable rapid industrial-scale use .…”

“…Catalysts driving this process should ideally be based on inexpensive metals and operate in the presence of water to enable rapid industrial-scale use . A number of earth-abundant metal complexes have been reported that are capable of catalyzing CO 2 reduction to CO or HCO 2 – through visible light-driven reactions. − Very recently, molecular transition metal catalysts capable of producing methane from carbon dioxide and visible light have emerged; however, reports of this reaction are rare. , Even more rare is the light-driven catalytic reduction of carbon dioxide to methane in the presence of solvent quantities of water . In fact, the vast majority of molecular photocatalytic systems for CO 2 reduction utilize anhydrous solvents such as acetonitrile or N , N -dimethylformamide .…”

Photocatalytic Reduction of CO2 to CO and Formate: Do Reaction Conditions or Ruthenium Catalysts Control Product Selectivity?

“…Most commonly, homogeneous catalysts in photocatalytic CO 2 reductions produce CO or HCO 2 – as the primary products. , Often selectivity for these products is rationalized as catalyst controlled with research focusing on catalyst design as a primary method of product selectivity control. However, a myriad of conditions are commonly used in homogeneous photocatalytic CO 2 reduction reactions including selection of (1) a CO 2 solubilizing solvent such as N , N -dimethylformamide (DMF) or acetonitrile (MeCN), (2) electron and proton sources such as 1,3-dimethyl-2-phenyl-2,3-dihydro-1 H -benzoimidazole (BIH), triethylamine (TEA), 1-benzyl-1,4-dihydronicotinamide (BNAH), or water, (3) a photosensitizer (PS) such as Ir III (ppy) 3 or [Ru II (bpy) 3 ] 2+ (where ppy is 2-phenylpyridine and bpy is 2,2′-bipyridine), and (4) a number of catalyst designs.…”

“…To probe the influence of each component, two ruthenium precatalysts were selected from the literature which are reported to be selective for formate in the case of [Ru II (bpy) 2 (CO) 2 ] 2+ and selective for CO in the case of [Ru II (C Me N OMe C Me )­(MeCN) 2 Cl] + (referred to as [Ru II (CNC)­Cl] + below) under the photocatalytic reaction conditions analyzed (Figure ). ,, For each catalyst, the solvent, photosensitizer, and proton and electron sources were varied systematically to elucidate the effect of each component on CO versus HCO 2 – selectivity.…”

Photoinduced Generation of a Durable Thermal Proton Reduction Catalyst with in Situ Conversion of Mn(bpy)(CO)3Br to Mn(bpy)2Br2

“…Proton reduction to H 2 is a commonly pursued approach in the search for a chemical fuel that can be derived from an abundant resource such as water. If the hydrogen evolution reaction is paired with water oxidation, only O 2 is generated as a stoichiometric waste . Ideally, these catalytic processes would be driven by robust catalysts derived from earth-abundant elements with fast rates of catalysis. , The catalysts should also durably operate with minimal driving force to avoid energetic losses .…”