Construction Of Photocatalytic Systems Research Articles

A Highly Efficient Supramolecular Polymer-Based Singlet Oxygen Generator for Photocatalytic Minisci Alkylation.

Supramolecular polymers, with their specific functional units and structures, can effectively enhance the absorption and utilization of light energy, thereby facilitating more efficient photocatalytic organic reactions. In the present work, we constructed a supramolecular polymer consisting of benzothiazole derivatives (BTBP) and cucurbit[8]uril (CB[8]). The BTBP monomer, known for its unique chemical structure and properties, has been found to exhibit a remarkable capability in generating singlet oxygen (1O2). As a result of the constraining impact of the macrocyclic molecule, the inclusion of CB[8] resulted in an effective enhancement in the ability to generate 1O2 while forming supramolecular polymer BTBP-CB[8]. When evaluating the quantum yield of 1O2 using Rose Bengal (RB) as a reference photosensitizer (75% in water), BTBP-CB[8] demonstrated an enhanced 1O2 quantum yield compared to BTBP, with an impressive yield of 152.4%, demonstrating that the formation of supramolecular polymer contributes to its ability to generate 1O2. Subsequently, BTBP-CB[8], a highly efficient 1O2 generator, was employed for the photocatalytic Minisci alkylation reaction, resulting in an impressive reaction yield of up to 89%. The supramolecular polymer strategies employed in the construction of photocatalytic systems have exhibited remarkable efficacy in the production of 1O2, underscoring their immense prospects in photocatalysis.

A Pyridine Anchoring Strategy for Dye‐Sensitized Photocatalysis

AbstractAnchoring groups play an important role in the assembly of functional molecules onto semiconductor substrates for dye‐sensitized photocatalysis. In addition to directly influencing the adsorption stability, anchoring groups significantly impact the efficiency of electron or hole injection into the substrate, which is a crucial step for photocatalytic reactions. Most reported dye‐sensitized photocatalytic systems, including semiconductor nanoparticles and photoelectrochemical cells, are prepared using the carboxylic or phosphonic acid anchors. The systems prepared with these conventional anchors usually suffer from low adsorption stability in aqueous media. Alternatively, pyridine has emerged as an anchoring group of photosensitizers and molecular catalysts in the construction of photocatalytic systems. The resulting semiconductor nanoparticles and photoelectrodes show superior adsorption stability in aqueous media, providing a simple and efficient way to sensitize the metal or metal oxide substrate. This review focuses on the recent advances of such a pyridine anchoring strategy in the assembly of photosensitizers and molecular catalysts for photocatalytic applications, mainly including photocatalytic water oxidation, reduction, and splitting. The further exploration and understanding of the pyridine‐anchoring method are believed to boost the development of advanced dye‐sensitized photocatalytic devices and technologies.

Coupling Long-Range Facet Junction and Interfacial Heterojunction via Edge-Selective Deposition for High-Performance Z-Scheme Photocatalyst.

The construction of photocatalytic systems that have strong redox capability, effective charge separation, and large reactive surfaces is of great scientific and practical interest. Herein, an edge‐connected 2D/2D Z‐scheme system that combines the facet junction and the interfacial heterojunction to achieve effective long‐range charge separation and large reactive surface exposure is designed and fabricated. The heterostructure is realized by the selective growth of 2D‐layered MoS2 nanoflakes on the edge‐sites of thin TiO2 nanosheets via an Au‐promoted photodeposition method. Attributed to the synergetic coupling of the facet junction and the interfacial heterojunction that assures the effective charge separation, and the tremendous but physically separated reactive sites offered by layered MoS2 and highly‐exposed (001) facets of TiO2, respectively, the artificial Z‐scheme exhibits excellent photocatalytic performance in photodegradation tests. Moreover, the junctional plasmonic Au nanoclusters not only act as electron traps to promote the edge‐selective synthesis but also generate “hot electrons” to further boost photocatalytic performance. The Z‐scheme charge‐flow direction in the heterostructure and the roles of electrons and holes are comprehensively studied using in situ irradiated X‐ray photoelectron spectroscopy and photodegradation tests. This work offers a new insight into designing high‐performance Z‐scheme photocatalytic systems.

Emerging Stacked Photocatalyst Design Enables Spatially Separated Ni(OH)2 Redox Cocatalysts for Overall CO2 Reduction and H2 O Oxidation.

Construction of photocatalytic systems with spatially separated dual cocatalysts is considered as a promising route to modulate charge separation/transfer, promote surface redox reactivities, and prevent unwanted reverse reactions. However, past efforts on the loading of spatially separated double-cocatalysts are limited to hollow structured semiconductors with inner/outer surface and monocrystalline semiconductors with different exposed facets. To overcome this limitation, herein, enabled by a unique stacked photocatalyst design, a facile and versatile strategy for spatial separation of redox cocatalysts on various semiconductors without structural and morphological restriction is demonstrated. The smart design begins with the deposition of light-harvesting semiconductors on reduced graphene oxide (rGO) nanosheets, followed with the coverage of Ni(OH)2 outer layer. The ternary photocatalysts exhibit superior activities and stabilities of H2 O oxidation and selective CO2 -to-CO reduction, remarkably surpassing other counterparts. The origin of the enhanced performance is attributed to the synergistic interplay of rGO@Ni(OH)2 reduction cocatalysts surrounding the semiconductors and Ni(OH)2 oxidation cocatalysts directly supported by the semiconductors, which mitigates the charge recombination, supplies highly active and selective sites for overall reactions, and preserves the semiconductors from photocorrosion. This work presents a new approach to regulating the position of dual cocatalysts and ameliorating the net efficiency of photoredox catalysis.