Katalyse der Kohlenstoffdioxid‐Photoreduktion an Nanoschichten: Grundlagen und Herausforderungen

Abstract

Die Umwandlung von CO2 in Treibstoffe und Chemikalien mithilfe der Photokatalyse ist eine vielversprechende Methode, um die Probleme der globalen Erwärmung und Energieversorgung nachhaltig zu lösen. Erfolge im Bereich der Photokatalyse während des letzten Jahrzehnts haben verstärktes Interesse an der Nutzung des Sonnenlichts zur Reduktion von CO2 hervorgerufen. Traditionelle Halbleiter in der Photokatalyse (z. B. TiO2) sind für die Anwendung in natürlichem Sonnenlicht nicht geeignet und sogar unter UV‐Bestrahlung nicht effizient genug. Kürzlich wurden einige zweidimensionale (2D) Materialien für die katalytische CO2‐Reduktion entwickelt. Diese Materialien müssen noch erheblich verbessert werden, was eine Herausforderung für die Entwicklung photokatalytischer Prozesse darstellt. Hier wird die Literatur über die photokatalytische CO2‐Umwandlung mit 2D‐Materialien in der Flüssigphase zusammengefasst, um eine Grundlage für die Suche nach verbesserten Materialien zu schaffen.

Dimension‐Matched Zinc Phthalocyanine/BiVO4 Ultrathin Nanocomposites for CO2 Reduction as Efficient Wide‐Visible‐Light‐Driven Photocatalysts via a Cascade Charge Transfer

“…H 2 Pc/ BVNS exhibits as imilar onset potential compared with that of BVNS,and as expected, it is much lower for ZnPc-coupled one,i ndicating that the ZnPc is more favorable for H 2 O reduction owing to the catalytic effect of zinc ions.B y comparison, the reduction behavior of CO 2 is also much preferred, and this result is consistent with CO 2 TPD curves (Supporting Information, Figure S25). Since the large p network of ZnPc is highly favorable for adsorption of CO 2 molecules through p-p interactions, [30] ZnPc/BVNS presents am uch larger adsorption amount of CO 2 molecules than those on the pristine BVNS.Meanwhile,itisnoticed that both H 2 Pc and ZnPc introduction are beneficial to improve the photocatalytic activity for CO 2 reduction, although ZnPccoupled one has better performance (Supporting Information, Figure S26a). Interestingly,i ti sv erified by the SPS responses and FS results that the enhanced charge separation on H 2 Pc/BVNS and ZnPc/BVNS is roughly same (Supporting Information, Figure S26b,c), indicating the important role of central metal in the catalysis to CO 2 reduction, rather than in the charge separation.…”

Recent progress of photocatalysts based on tungsten and related metals for nitrogen reduction to ammonia

“…The initial chemisorption and activation of N 2 could trigger the formation of different kinds of species in the subsequent reactions owing to multiple complicated electrons transferred hydrogenation procedures and the presence of reactive oxygen species by water oxidation half-reaction, such as oxygen, hydroxyl radicals •OH (2H 2 O+ 4h + → O 2 + 4H + , E 0 = 0.81 V vs. NHE at pH 7 or H 2 O+ h + → OH + H + , E 0 = 2.32 V vs. NHE at pH 7) (Sun et al, 2018). Adversely, the formed O 2 further captures electrons in the CB to suppress the NH 3 photosynthesis (Shiraishi et al, 2018;Sun et al, 2018) (Liu et al, 2012). The oxidation half-reaction products also oxidize the photogenerated NH 3 to HNO 3 , leading to a decrease in the NH 3 yield.…”

“…Transition metal chalcogenides (TMDs) have attracted heightened research interest for photocatalytic NRR primarily owing to their outstanding optical properties (wide spectral response range), relative nontoxicity, liquid media stability, superior electronic mobility, and intrinsic catalytic activity (Sun et al, 2018;Lei et al, 2020;Shen et al, 2020;Shen et al, 2021). Sun et al (2017) presented the trion-induced NRR on ultrathin sulfur-vacancies (SVs)-rich 2D MoS 2 , where photoexcited electron-hole pairs combined the doping-induced charges to form trions, bound multiple electrons and located around the Mo sites in MoS 2 , which lowered thermodynamic barriers and favored the simultaneous six-electron transfer to produce NH 3 .…”

“…The surfaces of many n-type and p-type semiconductors (such as sulphides) are susceptible to decomposition by photogenerated holes or electrons, decreasing the lifetimes of the photocatalysts. To address this issue, strategies such as coating with a second phase, surface passivation and functionalization and incorporation with cocatalysts can be employed (Sun et al, 2018).…”

Photocatalytic CO2 Reduction on TiO2‐Based Materials under Controlled Reaction Conditions: Systematic Insights from a Literature Study

“…The true formation of products from CO 2 as carbon source can be evidencedb yt hree general approaches:( 1) by the stoi-chiometric detection of the byproduct oxygen;t his is considered the bestw ay,b ecause it would also evidencet hat no sacrificial reagents are present and that the catalytic cycle is closed;(2) by 13 C-labeling of CO 2 and ad etection of 13 C-labeled products,o r( 3) the verification of the absence of product formation in ablank experiment, in which under otherwise similar reactionc onditions CO 2 has been replaced by an inert gas. [8] It is acknowledged that the latter two possibilities do not at the same time evidence that the catalytic cycle is truly closed.…”