Advancing photoreforming of organics: highlights on photocatalyst and system designs for selective oxidation reactions

Abstract

Photoreforming is a process that harnesses the redox ability of photocatalysts upon illumination, to simultaneously drive the reduction of H+ into hydrogen gas and oxidation of organic compounds. Over the...

A TiO2‐Co(terpyridine)2 Photocatalyst for the Selective Oxidation of Cellulose to Formate Coupled to the Reduction of CO2 to Syngas

“…[1][2][3][4] One green chemistry approach is the photooxidation of solid waste streams such as biomass coupled to the simultaneous reduction of protons for the generation of value-added oxidation products and the energy carrier H 2 . [5][6][7][8] This photoreforming (PR) process relies typically on as emiconductor particle that absorbs light to generate excited electrons to catalyze the reduction of water to H 2 ,w hile holes are being used to oxidize the organic waste. [5,9] An archetypical semiconductor for PR is TiO 2 coupled with various kinds of H 2 evolving co-catalysts such as Pt, RuO 2 ,M oS 2 or Ni 2 P, [10][11][12][13][14] especially as TiO 2 is as table,i nexpensive and scalable semiconductor suitable for PR of soluble biomass-derived substrates such as glucose.…”

Photodehydrogenation of Ethanol over Cu2O/TiO2 Heterostructures

“…In this context, biomass resources are a particularly compelling alternative source of hydrogen owing to their renewable character and their near net-zero CO 2 footprint [1][2][3][4][5][6]. Additional advantages of the hydrogen production from dehydrogenation of biomass-derived organics are the potential to co-produce valuable side organic chemicals for better process economics and the possibility to implement cost-effective waste abatement processes [7,8].…”

“…Additionally, bioethanol aqueous solutions can be directly used, without the need for purification. Compared with water splitting, the production of hydrogen from ethanol is thermodynamically advantageous (∆G 0 = +237 kJ•mol −1 for water oxidation vs. ∆G 0 = +41.5 kJ•mol −1 for ethanol oxidation to acetaldehyde), which decreases the energy input required to drive hydrogen production [2,8]. Compared with water splitting, ethanol dehydrogenation also enables a much simpler product purification, preventing the H 2 and O 2 back reaction.…”

“…To solve these limitations, Cu 2−x O can be combined with TiO 2 within p-n heterojunctions that protect Cu 2−x O against photocorrosion and reduce the charge carrier recombination. The synergism between the two materials is enabled by the appropriate conduction band edges of Cu 2−x O, −1.79 V for Cu 2 O and −1.03 V for CuO, which allows the rapid injection of the photogenerated electrons from the Cu 2−x O to the TiO 2 conduction band [8,[15][16][17][18][19]. Thus, the combination of Cu 2−x O and TiO 2 is regarded as a highly interesting photocatalyst to: (i) stabilize the Cu 2−x O, (ii) boost the overall catalytic activity by extending the light absorption of TiO 2 toward the visible light range and (iii) maximize external quantum yield by a rapid charge separation between the two phases enabled by their adequate band edges.…”

Facile one-step synthesis and enhanced photocatalytic activity of a WC/ferroelectric nanocomposite

“…1 In this respect, direct use of natural solar energy through photocatalysts represents an important area of technology. When refined the approach could be used to provide useful chemicals, 2 reduce CO2 in the atmosphere 3 or using narrow band-gap materials to produce fuels. 4 Despite abundant studies on semiconductors, including a variety of inorganic metal oxides (such as TiO2, ZnO, WO3 and SnO) [5][6][7][8][9] and sulfides (ZnS and CdS), [10][11][12][13][14] and the development of a variety of structures 15 their photocatalytic efficiency is still far from satisfactory.…”