Origin of photocatalytic activity in continuous gas phase CO(2) reduction over Pt/TiO(2)

Photocatalytic CO2 Reduction and Electrocatalytic H2 Evolution over Pt(0,II,IV)-Loaded Oxidized Ti Sheets

Energy recycling and production using abundant atmospheric CO₂ and H₂O have increasingly attracted attention for solving energy and environmental problems. Herein, Pt-loaded Ti sheets were prepared by sputter-deposition and Pt⁴⁺-reduction methods, and their catalytic activities on both photocatalytic CO₂ reduction and electrochemical hydrogen evolution were fully demonstrated. The surface chemical states were completely examined by X-ray photoelectron spectroscopy before and after CO₂ reduction. Gas chromatography confirmed that CO, CH₄, and CH₃OH were commonly produced as CO₂ reduction products with total yields up to 87.3, 26.9, and 88.0 μmol/mol, respectively for 700 °C-annealed Ti under UVC irradiation for 13 h. Pt-loading commonly negated the CO₂ reduction yields, but CH₄ selectivity was increased. Electrochemical hydrogen evolution reaction (HER) activity showed the highest activity for sputter-deposited Pt on 400 °C-annealed Ti with a HER current density of 10.5 mA/cm² at −0.5 V (vs. Ag/AgCl). The activities of CO₂ reduction and HER were found to be significantly dependent on both the nature of Ti support and the oxidation states (0,II,IV) of overlayer Pt. The present result could provide valuable information for designing efficient Pt/Ti-based CO₂ recycle photocatalysts and electrochemical hydrogen production catalysts.

Solar Fuels by Heterogeneous Photocatalysis: From Understanding Chemical Bases to Process Development

The development of sustainable yet efficient technologies to store solar light into high energy molecules, such as hydrocarbons and hydrogen, is a pivotal challenge in 21st century society. In the field of photocatalysis, a wide variety of chemical routes can be pursued to obtain solar fuels but the two most promising are carbon dioxide photoreduction and photoreforming of biomass-derived substrates. Despite their great potentialities, these technologies still need to be improved to represent a reliable alternative to traditional fuels, in terms of both catalyst design and photoreactor engineering. This review highlights the chemical fundamentals of different photocatalytic reactions for solar fuels production and provides a mechanistic insight on proposed reaction pathways. Also, possible cutting-edge strategies to obtain solar fuels are reported, focusing on how the chemical bases of the investigated reaction affect experimental choices.

Direct Coupling of Thermo- and Photocatalysis for Conversion of CO2 -H2 O into Fuels

Photocatalytic CO₂ reduction into renewable hydrocarbon solar fuels is considered as a promising strategy to simultaneously address global energy and environmental issues. This study focused on the direct coupling of photocatalytic water splitting and thermocatalytic hydrogenation of CO₂ in the conversion of CO₂ -H₂ O into fuels. Specifically, it was found that direct coupling of thermo- and photocatalysis over Au-Ru/TiO₂ leads to activity 15 times higher (T=358 K; ca. 99 % CH₄ selectivity) in the conversion of CO₂ -H₂ O into fuels than that of photocatalytic water splitting. This is ascribed to the promoting effect of thermocatalytic hydrogenation of CO₂ by hydrogen atoms generated in situ by photocatalytic water splitting.

Understanding synergetic effects of Zn and Rh–Cr promotion to wide-bandgap Ga, Ta and Ti oxides in photocatalytic water splitting

Zn and Rh–Cr promotion of photocatalytic materials as a versatile and valuable strategy to improve UV-light driven overall water splitting activity and the mechanisms of the promotional functions are uncovered.

Conversion of CO2 into renewable fuel over Pt–g-C3N4/KNbO3 composite photocatalyst

g-C₃N₄/KNbO₃ composite photocatalyst was prepared and developed for reduction of CO₂ into CH₄.

Cu2O/reduced graphene oxide composites for the photocatalytic conversion of CO2

A facile one-step microwave-assisted chemical method has been successfully used for the synthesis of Cu2O/reduced graphene oxide (RGO) composites. Photocatalytic CO2 reduction was then investigated on the junction under ambient conditions. The RGO coating dramatically increases Cu2O activity for CO2 photoreduction to result in a nearly six times higher activity than the optimized Cu2O and 50 times higher activity than the Cu2O/RuOx junction in the 20(th) hour. Furthermore, an apparent initial quantum yield of approximately 0.34 % at 400 nm has been achieved by the Cu2O/RGO junction for CO2 photoreduction. The photocurrent of the junction is nearly double that of the blank Cu2O photocathode. The improved activity together with the enhanced stability of Cu2O is attributed to the efficient charge separation and transfer to RGO as well as the protection function of RGO, which was proved by XRD, SEM, TEM, X-ray photoelectron spectroscopy, photo-electrochemical, photoluminescence, and impedance characterizations. This study further presents useful information for other photocatalyst modification for efficient CO2 reduction without the need for a noble-metal co-catalyst.