Search

An oxygen-vacancies-engaged photocatalytic mechanism was proposed to address the poor photo absorption and sluggish electron-hole separation of TiO 2. Electrons and holes are fully utilized for nitrobenzene reduction coupled with benzyl alcohol oxidation under visible light irradiation. • Oxygen vacancies (OVs) were generated through surface complexation under mild condition. • Fully making use of the photogenerated charge carriers rapidly promoted its separation and transfer efficiency. • Disclosing photoinduced electron transfer among photocatalysis. • The prepared TiO 2 exhibited good recyclability. Defects can greatly optimize the solar light harvesting capability and electronic structure of oxide materials. However, it remains challenging to achieve a defect engineering strategy under mild conditions. Meanwhile, the simultaneous exploitation of photogenerated holes (h+) and electrons (e−) to promote both photooxidation and photoreduction in a coupled system has rarely been reported. For the first time, we reveal an oxygen-vacancies-mediated photocatalytic strategy in which the electrons and holes are fully utilized for nitrobenzene reduction coupled with benzyl alcohol oxidation. The oxygen vacancies (OVs) generated in situ on the surface of TiO 2 greatly extend light absorption into the visible region and promote the photogenerated electron transport for efficient photocatalysis. The experimental and theoretical results together indicate that chemisorption on the TiO 2 surface decreases the oxidation potential of benzyl alcohol and causes an upward shift in its HOMO, which facilitates the oxidation reaction of benzyl alcohol to benzaldehyde. The in situ generated surface OVs also act as a bridge to enable the trapping and transferring of the photoinduced electrons to the nitrobenzene. This work provides a new perspective of utilizing the chemisorption between the reactant and catalyst to achieve a defect engineering strategy for synergetic photocatalysis. [ABSTRACT FROM AUTHOR]

• Multilayered wrinkled C 3 N 4 nanosheets is obtained via thermal-control synthesis. • The catalyst displays excellent selectivity, recycling stability, long-term durability, notable generality. • Cocatalysis of O 2 − and 1O 2 results in the unprecedented activity in sulfide oxidation. • The electron photoexcitation is valid under the competitive formation of charge carriers and excitons. Incorporating visible light into sulfide oxidation is an emerging desirable strategy to produce versatile sulfoxides. We introduce the design and synthesis of multilayered wrinkled C 3 N 4 nanosheets and demonstrate their unprecedented sulfide oxidation activity. Due to the wrinkled surfaces with a large S BET (208.6 m2g−1), wrinkled C 3 N 4 nanosheets exhibit a sensitive optical response, facilitating the electron photoexcition. Layer structure confinement enables robust e−-h+ interactions and valid photoexcited excitons formation, allowing rapid 1O 2 reactive species production. Integrating the sensitive optical response with robust e−-h+ interactions, photoexcited electrons and excitons are jointly produced, giving large yields of ⋅O 2 − and 1O 2 reactive species that are conductive to O 2 − and 1O 2 cocatalysis with an activity that is up to 33-fold that of bulk C 3 N 4. In the cocatalysis mechanism, both O 2 − and 1O 2 , can produce peroxysulfoxide intermediates, resulting in target sulfoxides. This is the first report on sulfide oxidation via O 2 − and 1O 2 cocatalysis and a promising study on catalyst exploitation for high-efficiency and high-selectivity production process. [ABSTRACT FROM AUTHOR]

The rational design and preparation of low-cost and visible-light-active catalysts for photodegradation of methylene blue (MB) have been regarded as an efficient way for the utilization of solar energy to address the environmental issues. Herein, in this work, a novel MoS 2 /CdS/Bi 2 MoO 6 ternary Z-scheme heterojunction to be applied in pollutant photodegradation is fabricated via hydrothermal method. Under visible light illumination, the as-prepared 2.4% MoS 2 /CdS/Bi 2 MoO 6 -2.0 composites display desirable photocatalytic activity with removal efficiency of 96.0% towards MB and the total organic carbon removal rate of 73.5% within 120 ​min. The apparent reaction rate constant of 2.4% MoS 2 /CdS/Bi 2 MoO 6 -2.0 (0.0256 min−1) is approximately 16 and 5.2 times higher than those of pure Bi 2 MoO 6 (0.0016 min−1) and CdS (0.0049 min−1), respectively. Meanwhile, the as-prepared ternary photocatalyst possess favorable universality. Combined with a series of characterization results, the enhanced photocatalytic activity of 2.4% MoS 2 /CdS/Bi 2 MoO 6 -2.0 is mainly attributed to the successful formation of the ternary Z-scheme photocatalysts, which could boost the separating/transferring efficiency and reduction/oxidation ability of charge carriers. In addition, the cycling experiments demonstrate that 2.4% MoS 2 /CdS/Bi 2 MoO 6 -2.0 possesses favorable stability and recoverability. Overall, this work put forward a simple strategy for synthesizing visible-light-active ternary Z-scheme photocatalytic materials. MoS 2 /CdS/Bi 2 MoO 6 ternary Z-scheme heterojunction has been successfully prepared via hydrothermal method, which exhibit the greatest photocatalytic activity with 96.0% of MB removal efficiency under visible light illumination. [Display omitted] • Preparation of MoS 2 /CdS/Bi 2 MoO 6 Z-scheme heterojunctions via a hydrothermalmethod • MoS 2 /CdS/Bi 2 MoO 6 heterojunctions inhibit the recombination of photogenerated carries. • MoS 2 /CdS/Bi 2 MoO 6 exhibits high photocataltic degradation efficiency. [ABSTRACT FROM AUTHOR]