A novel Ag/Bi3TaO7 plasmonic photocatalyst has been prepared by a simple photoreduction process. The as-prepared Ag/Bi3TaO7 photocatalyst exhibited an enhanced photocatalytic activity for the degradation of tetracycline (TC) compared to that of a bare Bi3TaO7 catalyst. The 1 wt % Ag-loaded Bi3TaO7 sample showed the highest photocatalytic efficiency for TC degradation (85.42%) compared with those of the other samples. The enhanced photocatalytic activity could be ascribed to the synergistic effect of the surface plasmon resonance caused by Ag nanoparticles. Electrochemical impedance spectroscopy demonstrated that the incorporation of silver nanoparticles onto the Bi3TaO7 surface promoted the separation of photogenerated carriers. In addition, an electron spin resonance (ESR) and trapping experiment revealed that the photoinduced active species hydroxyl radical and superoxide radical were the main active species in the photocatalytic process of TC degradation. The photocatalytic reaction mechanism was discussed by active species trapping and ESR analysis.

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The photoelectron transfer between semiconductors and cells is the rate-determining step that controls the solar H2 production of whole-cell inorganic-biohybrid systems (IBSs). Herein, we constructed an IBS by using reduced graphene oxide (RGO) to integrate Shewanella oneidensis MR-1 (SW) cells and Cu2O, which exhibited a 11–38-fold enhancement of photocatalytic H2 production compared with RGO-free IBSs (Cu2O/SW and Cu2O/organic electron mediator/SW). Further analysis revealed that RGO provided multifunctional contributions to H2 production from IBS, that is, sufficient area for IBS supporting, efficient photoelectron collection from Cu2O, and effective electron distribution into the cells. This study offers opportunities for rationally designing electron transfer pathways to achieve high-performance IBSs.

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inorganic-biohybrid system is of great interest because it merges the advantages of the inorganic photosensitizer with efficient light absorption and hydrogenase with high catalytic efficiency. [5][6][7][8] Accordingly, considerable efforts have been made to fabricate the purified hydrogenase biohybrid systems. [9][10][11][12][13][14][15][16] However, the low yield and complicated purification process of hydrogenase severely restrict the wide application of these biohybrid systems.A novel approach using whole cells expressing hydrogenases as the biocatalyst has shown obvious advantages over purified hydrogenases biohybrid system due to the easy fabrication and high stability. To date, two classes of whole-cell biohybrid systems were pursued, in the form of the extracellular photosensitized biohybrid system and the cytoplasmic photosensitized biohybrid system. [17][18][19][20][21][22][23] In the extracellular photosensitized biohybrid system (Figure S1a, Supporting Information), photoexcited electrons from extracellular photosensitizers were delivered to the hydrogenase in the cell through diffusional redox mediators or membrane-bound redox-active proteins, further realizing the solar hydrogen production. Honda and coworkers pioneered the fabrication of the TiO 2 /Escherichia coli extracellular photosensitized biohybrid system, which showed boosted photocatalytic H 2 production. [17] However, the extracellular photosensitized biohybrid system suffers from the sluggish electron transfer owing to the slow transmembrane process. To address this issue, a cytoplasmic photosensitized biohybrid system had been developed by implanting ultrasmall Au nanoclusters into the cytoplasm of Moorella thermoacetica and therefore realized durable solar-driven CO 2 fixation. [22] In this cytoplasmic photosensitized biohybrid system (Figure S1b, Supporting Information), interfacial electron transfer between the photosensitizer and the enzyme occurred in the cytoplasm, thereby avoiding energy loss during transmembrane electron transfer. This strategy provides new insight for the development of more efficient whole-cell biohybrid systems.It is known that there is a periplasmic space located between the outer membrane and the cytoplasm in the Gram-negative bacterial cell. [24] Compared to the cytoplasm, the periplasm is at a short distance from the outer membrane, where is favorable for light absorption. Furthermore, the narrow space Whole-cell inorganic-biohybrid systems, integrating inorganic photosensitizers with intact living cells, have shown great potential for solar hydrogen production. However, the typical whole cell biohybrid system often suffers from the sluggish kinetics of electron transfer in the transmembrane diffusion process, which severely restrict their photocatalytic activity. Here, a unique periplasmic photosensitized biohybrid system is constructed by translocating CuInS 2 /ZnS quantum dots (QDs) into the Shewanella oneidensis MR-1 (SW) cells that express periplasmic hydrogenases. The photoexcitation and electron tra...