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Mass transfer is an essential factor determining photocatalytic performance, which can be modulated by fluid field via manipulating the kinetic characteristics of photocatalysts and photocatalytic intermediates. Past decades have witnessed the efforts and achievements made in manipulating mass transfer based on photocatalyst structure and composition design, and thus, a critical survey that scrutinizes the recent progress in this topic is urgently necessitated. This review examines the basic principles of how mass transfer behavior impacts photocatalytic activity accompanying with the discussion on theoretical simulation calculation including fluid flow speed and pattern. Meanwhile, newly emerged viable photocatalytic micro/nanomotors with self‐thermophoresis, self‐diffusiophoresis, and bubble‐propulsion mechanisms as well as magnet‐actuated photocatalytic artificial cilia for facilitating mass transfer will be covered. Furthermore, their applications in photocatalytic hydrogen evolution, carbon dioxide reduction, organic pollution degradation, bacteria disinfection and so forth are scrutinized. Finally, a brief summary and future outlook are presented, providing a viable guideline to those working in photocatalysis, mass transfer, and other related fields. [ABSTRACT FROM AUTHOR]

Photocatalytic technology offers a practical way to solve the energy crisis by producing hydrogen under sunlight but its performance is encumbered by the fast recombination of photoinduced electron-hole pairs. Constructing heterojunctions to form built-in electric fields could separate these electrons and holes, finally enhancing the photocatalytic efficiency. Herein, a Mn 0.5 Cd 0.5 Se/g-C 3 N 4 (MCS/CN) heterojunction was fabricated by a facile method to tap into this advantage. 2%MCS/CN shows a hydrogen evolution rate of up to 354.5 μmol in 3 h, which is 4.49 and 126.6 times that of pure g-C 3 N 4 and Mn 0.5 Cd 0.5 Se, respectively. Its photocatalytic stability is proved by six cycling tests. Photocurrent, EIS, along with PL spectra, prove that the recombination of photoinduced electron-hole pairs is inhibited by constructing a heterojunction between Mn 0.5 Cd 0.5 Se and g-C 3 N 4. In summary, this work demonstrates the enhancement of photocatalysis by constructing a S-scheme heterojunction and offers a feasible way to develop other effective photocatalysts. • Mn 0.5 Cd 0.5 Se/g-C 3 N 4 S-scheme heterojunction was constructed by a facile solvothermal method. • Photocatalytic performance was enhanced greatly by fast carrier separation. • The nanosheets-nanoparticles heterojunction provides a general avenue to design other photocatalysts. [ABSTRACT FROM AUTHOR]

Fast recombination of photoinduced carriers inhibits the performance of photocatalysts. By constructing heterojunctions, built-in electric fields can be formed to separate electrons and holes and finally enhance the photocatalytic efficiency. Herein, a MnxCd1−xSe in situ heterojunction was fabricated by a facile solvothermal method to draw upon this advantage. Absorption spectra show that the light absorption of CdSe raises up obviously after the doping of Mn2+. Best performance was achieved when the doping percent of Mn2+ was 50%. This Mn0.5Cd0.5Se sample exhibits a 7.2 folds increase in hydrogen evolution against pure CdSe owing to the fast electron transportation. Moreover, it proves well stability in an 18 h cycling test and gains a 6.7% apparent quantum yield under 420 nm light. In summary, this work constructs an in situ heterojunction to enhance the photocatalytic hydrogen evolution efficiency and sheds light on a feasible way for the application of photocatalysis. [ABSTRACT FROM AUTHOR]

Utilizing cocatalysts is an effective measure to enhance photocatalytic activities of photocatalysts. Nevertheless, noble-metal cocatalysts such as Pt and Au impose astounding costs on the application of photocatalytic technology. Herein, noble-metal-free MoS2 was used as a cocatalyst to improve the photocatalytic activity of visible-light-responsive TaON for the first time. This work indicates that MoS2/TaON presented higher activity than Pt/TaON while MoS2 costs much less than Pt. The photocatalytic degradation ratio of RhB over Ta1Mo1 (mass ratio of TaON:MoS2 = 1:1) was about 65% after 2 h visible light irradiation, which is about five times higher than that of pure TaON. Furthermore, MoS2/SiO2/TaON ternary photocatalysts were constructed to further improve the photocatalytic performance. When the mass ratio of Ta8Si1 (mass ratio of TaON:SiO2 = 8:1) to MoS2 was 1:1, the degradation ratio of RhB reached 75% after 2 h visible light irradiation. This work provides a facile method to construct high-efficient photocatalysts with the noble-metal-free cocatalyst MoS2, paving the way to realize the application of cheap and environment-friendly photocatalysis. [ABSTRACT FROM AUTHOR]