Tailoring Surface Frustrated Lewis Pairs of In2O3−x(OH)y for Gas‐Phase Heterogeneous Photocatalytic Reduction of CO2 by Isomorphous Substitution of In3+ with Bi3+

Lü

et al. 2018

Adv Funct Materials

128

Light-driven CO 2 reduction into high value-added product is a potential route to convert and store solar energy. Here, using the hydroxyls on an oxyhydroxide photocatalyst, CoGeO 2 (OH) 2 , as solid-state proton source to reduce the CO 2 into CH 4 is proposed. It is found that under irradiation, the lattice hydroxyls on surface of CoGeO 2 (OH) 2 are oxidized by photogenerated holes, resulting in the generation of oxygen vacancies (O Vs ) and protons. The photoinduced O Vs (Lewis acid) and its proximal surface hydroxyls (Lewis base) are more likely to form the frustrated Lewis acid-base pairs, which can capture, activate, and reduce CO 2 with the assistance of protons into CH 4 . The surface lattice hydroxyls are able to regenerate when the catalyst is exposed to the water molecule-containing atmosphere, thus achieving a sustainable CO 2 conversion. The proposed CO 2 reduction by self-breathing surface hydroxyls may open a new avenue to use photocatalysis for energy conversion.

Section: Resultssupporting

confidence: 72%

Frustrated Lewis Pairs Accelerating CO₂ Reduction on Oxyhydroxide Photocatalysts with Surface Lattice Hydroxyls as a Solid‐State Proton Donor

Lü

et al. 2018

Adv Funct Materials

128

“…In order to expanding the limited optical adsorption of In 2 O 3 under sunlight, there have been persistent efforts to alter the material composition of In 2 O 3 , such as element doping, precious metals supporting, and nanostructured substance coating . For example, when Bi metallic dopants are introduced, the optical adsorption can be modified as the result of electronic hybridization between Bi 6s and O 2p orbitals, upwardly shifting the valence band (VB) and consequently reducing bandgap . Recently, Ozin group report a hybrid catalyst consisting of a vertically aligned silicon nanowire (SiNW) support evenly coated by In 2 O 3− x (OH) y nanoparticles to minimized reflection losses and enhanced light trapping within the SiNW support .…”

Section: Methodsmentioning

confidence: 97%

Photoinduced Defect Engineering: Enhanced Photothermal Catalytic Performance of 2D Black In₂O₃₋_x Nanosheets with Bifunctional Oxygen Vacancies

et al. 2019

alternative clean energy supplies and pollution-free technologies turns out to be high priority. [1,2] The CO 2 reduction project plays a pivotal role in response to the concerns because of its capability of exhausted gas consumption and combustible fuels generation. [3][4][5][6] Gas-phase thermal reduction of CO 2 to CO via endothermic reverse water gas shift (RWGS) reaction becomes an attractive strategy on account of abundant accessibility of thermal catalytic active sites. On the same time removing excessive CO 2 in atmosphere, the emitted CO can be also utilized directly as the feedstock for further fuel manufacturing (e.g., via the Fischer-Tropsch process). [7][8][9][10] However, to achieve purposeful CO 2 conversion, massive nonrenewable energy is indispensable to be invested in the reaction. Compared with traditional energy, alternative inexhaustible energy input has been discovered via photothermal process which effectively utilizes full spectrum of sunlight to lead accurate heating location and instantaneously raise the surface temperature of the catalysts. [11][12][13][14][15][16] Indium-oxide-based materials are a typical thermal catalyst with potential prospect for photothermal reduction of CO 2 . Its catalytic active sites promote the adsorption and activation for thermochemical CO 2 hydrogenation, [17,18] but the wide band (2.8 eV) is unfavorable for photothermal conversion for a long time. In order to expanding the limited optical adsorption of In 2 O 3 under sunlight, there have been persistent efforts to alter the material composition of In 2 O 3 , such as element doping, [19] precious metals supporting, [20] and nanostructured substance coating. [21] For example, when Bi metallic dopants are introduced, the optical adsorption can be modified as the result of electronic hybridization between Bi 6s and O 2p orbitals, upwardly shifting the valence band (VB) and consequently reducing bandgap. [22] Recently, Ozin group report a hybrid catalyst consisting of a vertically aligned silicon nanowire (SiNW) support evenly coated by In 2 O 3−x (OH) y nanoparticles to minimized reflection losses and enhanced light trapping within the SiNW support. [23] Basically, eminent photothermal catalysts are composite materials, but the pure ones have not come up yet. In order to construct various active sites to activate wide range of reactants, designing and modulating Photothermal CO 2 reduction technology has attracted tremendous interest as a solution for the greenhouse effect and energy crisis, and thereby it plays a critical role in solving environmental problems and generating economic benefits. In 2 O 3−x has emerged as a potential photothermal catalyst for CO 2 conversion into CO via the light-driven reverse water gas shift reaction. However, it is still a challenge to modulate the structural and electronic characteristics of In 2 O 3 to enhance photothermocatalytic activity synergistically. In this work, a novel route to activate inert In(OH) 3 into 2D black In 2 O 3−x nanosheets via photoinduced defect eng...

Advanced Energy Materials

“…However only at specific sites, in which there are Lewis‐basic OH and Lewis‐acidic unsaturated In atoms, can small gas molecules like CO 2 be activated. For example, Dong et al doped bismuth into the lattice of In 2 O 3− x (OH) y to promote efficiency in photoreduction of CO 2 . The In 3+ ions were substituted by Bi 3+ ions of which the 6s 2 electrons pairs hybridize with the oxygen of InOH resulting in increasing the basicity of this Lewis base.…”

Section: Frustrated Lewis Pairs (Flps)mentioning

confidence: 99%

Atomic‐Level Reactive Sites for Semiconductor‐Based Photocatalytic CO₂ Reduction

Zhang

Xia

Ran

et al. 2020

350

252

Photocatalytic CO2 reduction is an effective means to generate renewable energy. It involves redox reactions, reduction of CO2 and oxidation of water, that leads to the production of solar fuel. Significant research effort has therefore been made to develop inexpensive and practically sustainable semiconductor‐based photocatalysts. The exploration of atomic‐level active sites on the surface of semiconductors can result in an improved understanding of the mechanism of CO2 photoreduction. This can be applied to the design and synthesis of efficient photocatalysts. In this review, atomic‐level reactive sites are classified into four types: vacancies, single atoms, surface functional groups, and frustrated Lewis pairs (FLPs). These different photocatalytic reactive sites are shown to have varied affinity to reactants, intermediates, and products. This changes pathways for CO2 reduction and significantly impacts catalytic activity and selectivity. The design of a photocatalyst from an atomic‐level perspective can therefore be used to maximize atomic utilization efficiency and lead to a high selectivity. The prospects for fabrication of effective photocatalysts based on an in‐depth understanding are highlighted.