Boosted Inner Surface Charge Transfer in Perovskite Nanodots@Mesoporous Titania Frameworks for Efficient and Selective Photocatalytic CO₂ Reduction to Methane

Abstract

Exploring high‐efficiency and stable halide perovskite‐based photocatalysts for the selective reduction of CO2 to methane is a challenge because of the intrinsic photo‐ and chemical instability of halide perovskites. In this study, halide perovskites (Cs3Bi2Br9 and Cs2AgBiBr6) were grown in situ in mesoporous TiO2 frameworks for an efficient CO2 reduction. Benchmarked CH4 production rates of 32.9 and 24.2 μmol g−1 h−1 with selectivities of 88.7 % and 84.2 %, were achieved, respectively, which are better than most reported halide perovskite photocatalysts. Focused ion‐beam sliced‐imaging techniques were used to directly image the hyperdispersed perovskite nanodots confined in mesopores with tunable sizes ranging from 3.8 to 9.9 nm. In situ X‐ray photoelectronic spectroscopy and Kelvin probe force microscopy showed that the built‐in electric field between the perovskite nanodots and mesoporous titania channels efficiently promoted photo‐induced charge transfer. Density functional theory calculations indicate that the high methane selectivity was attributed to the Bi‐adsorption‐mediated hydrogenation of *CO to *HCO that dominates CO desorption.

Inorganic Copper-Based Halide Perovskite for Efficient Photocatalytic CO2 Reduction

“…Therefore, replacing Pb 2+ with an environmentally friendly metal ion to develop low toxic halide perovskite with excellent photoelectrical properties is of great research and practical application significance. To date, Sn-, Sb-, and Bi-based single and double perovskites, such as CsSnCl 3 , Cs 3 Bi 2 Br 9 , , Cs 3 Sb 2 Br 9 , and Cs 2 AgBiBr 6 , , have been successfully demonstrated as photocatalysts for CO 2 reduction, which offered a wider choice of photocatalyst materials.…”

Design and synthesis of an S-scheme TiO2homojunction with an adjusted, well-defined phase for directional carrier transfer in solar water splitting

“…Binding energy is negatively related to surface electron density, 28 this means that the anatase and rutile TiO 2 in TiO 2 -TELMs were closely connected due to the formation of homojunction structures, and the electron density gradually increases with increasing the ratio of rutile TiO 2 . 29–31 When the ratio of rutile TiO 2 exceeds to a certain value, for example 65% in this work, the electron density of TiO 2 in the TiO 2 -TELM sample gradually decreases, and the electrons transfer from rutile to anatase TiO 2 . Therefore, this suggests that the electron transfer from anatase to rutile or from rutile to anatase should be adjusted by the ratio of rutile or anatase in TiO 2 -TELMs.…”

Recent advances and potential applications of flexible adsorption and separation materials: A review

“…Recently, the demand for fossil energy, such as oil and coal, has significantly increased worldwide, causing a severe energy crisis. 109 Therefore, solid-gas separation and storage technology has received much attention from researchers as an efficient and straightforward energy storage technology. Solid gas separation and storage technology can separate important industrial gases, such as CO 2 , from mixed waste gases and store them in solid media for backup.…”

“…Recently, the demand for fossil energy, such as oil and coal, has significantly increased worldwide, causing a severe energy crisis 109 . Therefore, solid‐gas separation and storage technology has received much attention from researchers as an efficient and straightforward energy storage technology.…”