Operando FTIR study of the photocatalytic reduction of CO₂ in the presence of water vapor over Pt/TiO₂: on the role of surface residual C-species

Abstract

Benchmark TiO2 and Pt/TiO2 photocatalysts were investigated by operando FTIR spectroscopy to shed light on catalytic pathways influencing CO2 photoreduction in vapor phase. Through combination with multivariate curve resolution-chemometric analysis,...

Exploring the effect of the reaction conditions on the mechanism of the photocatalytic reduction of CO2 in the vapor phase over Pt/TiO2: an operando FTIR study

“…S4†) are chemically reactive and capable of being readily converted into intermediates/products under irradiation as reported in our previous study. 5…”

“…2 Moreover, recent studies have also evidenced the formation of C2 products through C–C coupling mechanisms, such as ethane (C 2 H 6 ), ethanol (C 2 H 5 OH), ethylene (C 2 H 4 ) and acetic acid (CH 3 COOH). 3–5…”

“…Carbon-containing species, originating from synthesis procedures or storage conditions, may reside on the surface of the sample and potentially contribute to product formation, leading to an overestimation of product formation rates and overall yields of the reaction. Despite the well-documented involvement of carbon residues in photocatalytic activity, 5,13 the unambiguous identification of impurities and their specific impact on photoactivity during the reaction remains a persistent challenge.…”

“…In this context, a continuous flow operando gas-phase photoreactor equipped with Fourier transform infrared spectroscopy surface analysis in transmission mode was developed 5,26 to investigate the vapor-phase photocatalytic reduction of CO 2 . This methodology employs the simultaneous analysis of the products of the reaction and the catalytic surface, which makes it possible to acquire a better understanding of the correlation between the structure and performance of the catalysts.…”

Evidence on C–C Coupling to Acetate as Key Reaction Intermediate in Photocatalytic Reduction of CO2 over Pt/TiO2

“…12 These residues, originating from catalyst preparation or organic compound adsorption, can contribute to reaction products, complicating the attribution of products solely to CO 2 reduction. 13 Our previous study demonstrated that carbon residues significantly impact CO 2 photocatalytic reduction, accounting for up to 40% of methane yields. 14 Given the low yields of CO 2 conversion, it is crucial to distinguish between products from residual-carbon impurities and those from the reduction of CO 2 to better understand the underlying reaction mechanisms.…”