Alkaline Co(OH)₂-Decorated 2D Monolayer Titanic Acid Nanosheets for Enhanced Photocatalytic Syngas Production from CO₂

Abstract

The difficulty of adsorption and activation of CO2 at the catalytic site and rapid recombination of photogenerated charge carriers severely restrict the CO2 conversion efficiency. Here, we fabricate a novel alkaline Co­(OH)2-decorated ultrathin 2D titanic acid nanosheet (H2Ti6O13) catalyst, which rationally couples the structural and functional merits of ultrathin 2D supports with catalytically active Co species. Alkaline Co­(OH)2 beneficially binds and activates CO2 molecules, while monolayer H2Ti6O13 acts as an electron relay that bridges a photosensitizer with Co­(OH)2 catalytic sites. As such, photoexcited charges can be efficiently channeled from light absorbers to activated CO2 molecules through the ultrathin hybrid Co­(OH)2/H2Ti6O13 composite, thereby producing syngas (CO/H2 mixture) from photoreduction of CO2. High evolution rates of 56.5 μmol h–1 for CO and 59.3 μmol h–1 for H2 are achieved over optimal Co­(OH)2/H2Ti6O13 by visible light illumination. In addition, the CO/H2 ratio can be facilely tuned from 1:1 to 1:2.4 by changing the Co­(OH)2 content, thus presenting a feasible approach to controllably synthesize different H2/CO mixtures for target applications.

Photocatalytic Anaerobic Oxidation of Aromatic Alcohols Coupled With H2 Production Over CsPbBr3/GO-Pt Catalysts

“…To further study the influence of the introduction of GO and Pt on charge separation and migration, a series of photoelectrochemical characterizations over blank CsPbBr 3 , CPB/GO, and CPB/GO-Pt composites have been carried out. As shown in Figure 2A , the photocurrent response tests of these samples reveal that the CPB/GO-Pt hybrid composite (taking CPB/1.0% GO-1%Pt with optimal photoactivity as an example) displays higher current density than blank CsPbBr 3 and CPB/GO samples, indicating a more efficient separation of the photogenerated carrier ( Liao et al, 2021 ). Figure 2B presents the electrochemical impedance spectroscopy (EIS) study of these samples, which is employed to study the charge transfer resistance of the samples.…”

A critical review on emerging photocatalysts for syngas generation via CO2 reduction under aqueous media: a sustainable paradigm

“…21,28 As we have mentioned earlier, different approaches have been adopted from time to time for syngas production, but the solar-driven approach is one of the pioneering ones. 16,26,29 Over a decade, numerous studies have been conducted on photocatalytic CO 2 reduction and significant efforts have been made to develop new photocatalytic systems to increase photocatalytic performance. [30][31][32][33][34] In addition, there are plenty of reviews and perspectives on photocatalytic CO 2 reduction that mainly discuss the challenges in CO 2 photoreduction for solar fuel production, the different types of photocatalytic systems for CO 2 reduction, improvement in the photo selectivity of solar fuels, and advancements in the structural engineering of photocatalysts for solar-driven CO 2 reduction into fuels.…”

“…21,28 As we have mentioned earlier, different approaches have been adopted from time to time for syngas production, but the solar-driven approach is one of the pioneering ones. 16,26,29 Over a decade, numerous studies have been conducted on photocatalytic CO 2 reduction and significant efforts have been made to develop new photocatalytic systems to increase photocatalytic performance. 30–34…”

Controllable Visible-Light-Driven Syngas Evolution by a Ternary Titania Hybrid Sacrificial System with a Photosensitive Metal–Organic PdII Cage and ReI Catalyst

“…The huge consumption of global energy causes a sharp reduction of traditional fossil fuels and increases the concentration of atmospheric CO 2 that induces severe environmental issues including global warming and ocean acidification. − Using photocatalytic technology to decompose water and reduce carbon dioxide for producing “solar fuel” is an effective method to alleviate energy shortage and natural environment deterioration. − Syngas, a mixture of H 2 and CO, is a critical raw material for the production of bulk chemicals and active alternative fuel through the Fischer–Tropsch processing. The control of the CO/H 2 ratio in syngas is very important for the synthesis of useful chemicals, and generally CO/H 2 mixtures with a ratio of 1:1 or 1:2 can produce aldehydes or methanol. , However, less effort has been made in photocatalytic controllable syngas generation than pure H 2 and CO production. − In 1983, Lehn and co-workers initially developed several Re­(bipy)­(CO) 3 X complexes for photocatalytic conversion of CO 2 to CO, which attracted much attention due to their effectiveness and selectivity . In 2015, Reisner and co-workers immobilized a Re bipyridine photocatalyst fac-[Re­(2,2′-bipyridine-4,4′-bisphosphonic acid)­(CO) 3 (Cl)] (ReP) on TiO 2 particles to form heterogeneous catalysts, obtaining significantly enhanced durability and activity .…”