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Metal–organic framework (MOF) materials have been extensively incorporated with inorganic semiconductor photocatalysts to improve their photocatalytic activity through an efficient charge transfer process across their heterointerface. In this work, octahedral UiO-66-NH2 MOFs with edge-lengths of 110–330 nm are uniformly decorated on the surface of TiO2 electrospun nanofibers by a traditional solvothermal method combined with activation pretreatment. Before the solvothermal growth of UiO-66-NH2, the TiO2 electrospun nanofibers were activated in NaOH solution to etch the TiO2 surface for allowing the exposure of lattice oxygen. The exposed lattice oxygen on the TiO2 surface could interact with the MOF precursor of Zr4+ ions, thus enabling octahedral UiO-66-NH2 to grow uniformly on the surface of TiO2 nanofibers with an intimate Ti–O–Zr hetero-interface. Such an intimate hetero-interface provides an effective channel for boosting the electron transfer between UiO-66-NH2 and TiO2 in their heterostructure. Thus, the UiO-66-NH2/TiO2(anatase) heterostructures exhibited enhanced photocatalytic activity for H2 production as compared to either TiO2(anatase) nanofibers or UiO-66-NH2 nanooctahedra in the presence of Rhodamine B (RhB) as a sensitizer under visible light irradiation. In particular, the decoration of UiO-66-NH2 nanooctahedra on anatase/rutile mixed TiO2 nanofibers could induce further enhancement of the photocatalytic H2 production. The enhanced photocatalytic activity is attributed to the multi-step continuous interfacial transfer of photoinduced electrons with the way of RhB → UiO-66-NH2 → TiO2(anatase) → TiO2(rutile). [ABSTRACT FROM AUTHOR]

The photocatalytic activity of a semiconductor is heavily influenced by its photocatalytic cumulative effect on the four consecutive photo-physiochemical processes, including light harvesting, charge separation, charge migration, and charge utilization. Herein, we proposed and synthesized the well-designed plasmonic Au@Pt/CdS/C 3 N 4 heterostructure to enhance the photocatalytic cumulative effect by simultaneously sensitizing the total four processes. [Display omitted] • Pt/CdS-selective-coated Au nanocubes are assembled onto C 3 N 4 nanosheets. • Plasmon-enhanced photocatalytic cumulative effect on the Au@Pt/CdS/C 3 N 4 heterostructure. • Plasmon-induced HET, RET, and LEFE processes are achieved simultaneously. • Photocatalytic activities of H 2 generation and CO 2 reduction are remarkably enhanced. The photocatalytic activity of a semiconductor is heavily influenced by its photocatalytic cumulative effect on the four consecutive photo-physiochemical processes, including (I) light harvesting, (II) charge separation, (III) charge migration, and (IV) charge utilization. However, it is still a tremendous challenge to enhance the photocatalytic cumulative effect by simultaneously sensitizing the total above I-IV processes of the semiconductor. Herein, we synthesized the well-designed plasmonic Au@Pt/CdS/C 3 N 4 heterostructure through assembling Pt/CdS-selective-coated Au nanocubes onto the two dimensional (2D) ultrathin C 3 N 4 nanosheets (NSs). We have also demonstrated that selectively coating CdS nanoparticle-clusters (NPCs) and Pt nanoparticles (NPs) onto the surfaces and edges of Au NCs could boost the II and III processes of the formed Au@Pt/CdS NCs based on the resonance energy transfer (RET) and "hot electron" transfer (HET) behaviors, respectively, due to the localized surface plasmon resonance (LSPR) of Au NCs. The assembly of the Au@Pt/CdS NCs onto the C 3 N 4 NSs formed lots of 2D Au/CdS/C 3 N 4 interface, where the Au-LSPR not only boosted the I process at the "type II" heterojunction regions of CdS/C 3 N 4 , but also improved the II process of C 3 N 4 NSs via the local electromagnetic field enhancement (LEFE). Furthermore, the quasi-2D porous structure of CdS NPCs increased the surface active-sites at the 2D CdS/C 3 N 4 interface, therefore enhancing the IV process. As such, when normalizing the effective active area as the Au@Pt/CdS/C 3 N 4 hetero-interface region, the plasmonic heterostructure exhibited the ∼ 17.2-fold and ∼ 14.3-fold enhancements on the photocatalytic H 2 evolution and CO 2 reduction as compared to the CdS/C 3 N 4 heterojunction, respectively. [ABSTRACT FROM AUTHOR]

In this work, we present the 2D/2D type of heterojunction photocatalysts fabricated by horizontal loading ultrathin hexagonal SnS 2 nanosheets on g-C 3 N 4 nanosheets through a facile ultrasonic dispersion method. The sheet-like structures of these two nanomaterials induce a large contact region in the heterojunction interface, as evidenced by electron microscopic analyses. By taking advantage of this feature, the as-fabricated SnS 2 /g-C 3 N 4 heterojunction nanosheets exhibit considerable improvement on the photocatalytic activities for the degradation of organic dyes and phenols under visible light irradiation as compared to pure g-C 3 N 4 and SnS 2 nanosheets. In particular, the optimal heterojunction nanosheet with 5.0 wt.% SnS 2 shows the apparent rate constant of ∼0.2 min −1 for the RhB photodegradation, which is higher than that of pure g-C 3 N 4 and SnS 2 nanosheets by a factor of 4 and 8, respectively. Further studies by steady-state and transient photoluminescence spectroscopy indicate that the photosynergistic effect of SnS 2 /g-C 3 N 4 heterojunction can remarkably enhance the photoinduced interfacial charge transfer, thereby increasing the charge separation during the photocatalytic reaction. [ABSTRACT FROM AUTHOR]

We present high-yield hydrogen production through selective photocatalytic decomposition of formic acid by using electrospun TiO 2 nanofibers decorated with AuPd bimetallic alloy nanoparticles under simulated sunlight irradiation. By using only 5 mg of the AuPd/TiO 2 nanofibers containing the 0.75% Au and 0.25% Pd, we could achieve an optimal H 2 generation rate of 88.5 μmol h −1 with an apparent quantum yield at 365 nm as 15.6%, which is higher than that of the Pd/TiO 2 and Au/TiO 2 nanofibers by a factor of 1.6 and 4.5, respectively. The enhanced photocatalytic decomposition of formic acid for H 2 generation could be attributed to the stronger electron-sink effect of AuPd alloy nanoparticles, the high selectivity of Pd for the dehydrogenation of formic acid, and the surface plasmon resonance effect of Au. More importantly, we demonstrate that the photocatalytic processes enable re-activation of the AuPd nanoparticles that were poisoned by CO during thermal decomposition of formic acid. As such, the presented AuPd/TiO 2 nanofibers are promising materials for re-generation of H 2 under mild conditions from liquid storage carrier of hydrogen. [ABSTRACT FROM AUTHOR]

Amine-functionalization of TiO2 nanoparticles, through a solvothermal approach, substantially increases the affinity of CO2 on TiO2 surfaces through chemisorption. This chemisorption allows for more effective activation of CO2 and charge transfer from excited TiO2, and significantly enhances the photocatalytic rate of CO2 reduction into methane and CO. [ABSTRACT FROM AUTHOR]

In this work, the lacunary Keggin-type phosphotungstates of [PW9O34]9- (PW9) clusters were loaded onto the g-C3N4 nanosheets (NSs) to synthesize the phosphotungstate clusters-decorated 2D heterojunction photocatalysts by using the electrostatic-force driven self-assembly process. The surface charge polarity of g-C3N4 NSs was changed from a negative to a positive charge through the acidizing treatment. The positively-charged g-C3N4 NSs allowed the negatively-charged PW9 clusters to be adsorbed and deposited onto the g-C3N4 NSs, forming the PW9/g-C3N4 heterojunction NSs. The as-synthesized samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and UV-VIS absorption spectra, respectively. The photocatalytic activity tests indicated that, upon simulated sunlight irradiation, the photocatalytic H2-generation rate of PW9/g-C3N4 heterojunction NSs (~23.8 μmol h−1) was ~3.3 times higher than that of the pure g-C3N4 NSs (~7.3 μmol h−1). The enhanced photocatalytic activity of PW9 cluster-decorated g-C3N4 NSs could be attributed to the enhanced separation process of the photoinduced charge-carriers, due to the Z-scheme-mediate charge transfer behavior across their hetero-interface. [ABSTRACT FROM AUTHOR]

With the rapid development of industry, organic pollutants and bacterial contamination in water resources are becoming increasingly severe. Photocatalysis is an effective approach to address this problem. ZnO, as a traditional n- type semiconductor photocatalyst, has a relatively wide bandgap, which results in a narrow range of light absorption and quick recombination of photogenerated charge carriers, thus limiting its development. In this work, we constructed p -type CuO/ n -type ZnO heterojunction nanofibers (HNFs) to extend the light harvesting range and improve the migration and separation of the photoinduced electrons and holes across the hetero-interface through. Afterwards, Ag nanoparticles were introduced into above HNF matrix to reinforce the photocatalytic activity. Results showed that, upon simulated sunlight irradiation, the Ag NPs-decorated p- type CuO/ n- type ZnO HNFs exhibited enhanced photocatalytic activities. After 20 min of simulated sunlight irradiation, approximately 98.5% of MB was degraded by 1.0 at% Ag NPs-decorated p- type CuO/ n- type ZnO HNFs. Additionally, after 10 min of irradiation, the disinfection efficiency of HNFs for Escherichia coli was > 99.99%. It is worth noting that this study has opened up a new pathway for the rational design of p-n junction photocatalysts with superior charge transfer properties, to achieve remarkable photocatalytic disinfection and degradation activities. [Display omitted] • A p -type CuO/ n -type ZnO photocatalyst was prepared, leading to the broadening of photoabsorption in the visible region. • The CuO/ZnO nanofibers possess excellent photocatalytic activity for the degradation of MB and disinfection of E. coli. • To further enhance the activity of binary photocatalysts, Ag nanoparticles were successfully modified on CuO/ZnO HNFs. • Ag nanoparticles-modified CuO/ZnO HNFs photocatalysts exhibit rapid dye degradation and bactericidal activity (<30 min). [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of 2D g-C 3 N 4 /SnS 2 /TiO 2 ternary photocatalyst was present. • g-C 3 N 4 /SnS 2 /TiO 2 showed broad photoresponsive range and promoted charge separation. • The continuous charge steps were fabricated at the hetero-interface of catalyst. • The photocatalytic disinfection activity of g-C 3 N 4 /SnS 2 /TiO 2 was highly enhanced. • Both O 2 - and h+ are responsible for photocatalytic process of g-C 3 N 4 /SnS 2 /TiO 2. The development of inexpensive and high-efficient semiconductor photocatalysts is of great significance for achieving the goal of environmental remediation. However, the fast recombination of the photoinduced charge-carriers in semiconductor photocatalysts still poses a huge obstacle. In this contribution, we pave "continuous charge steps" in multiple 2D-semiconductor hetero-interface through an orderly assembly of 2D semiconductors of g-C 3 N 4 , SnS 2 , and TiO 2 nanosheets (NSs) by using a facile ultrasonic dispersion and subsequent heat treatment. The matchable energy band structures between the above three 2D NSs allows their orderly composite (g-C 3 N 4 /SnS 2 /TiO 2 NSs) to possess two kinds of broad 2D hetero-interface configurations (g-C 3 N 4 /SnS 2 /TiO 2 and TiO 2 /g-C 3 N 4 /SnS 2) with the extended light-harvesting range. The time-resolved photoluminescence spectroscopy results prove that both of the above hetero-interface configurations could induce the formation of "continuous charge steps" to accelerate the interfacial electron transfer. Thus, upon UV–visible light irradiation, the as-synthesized g-C 3 N 4 /SnS 2 /TiO 2 NSs exhibited 4.2–7.5 fold enhancement for the photocatalytic degradation of Rhodamine B. Notably, the photocatalytic disinfection efficiency of the g-C 3 N 4 /SnS 2 /TiO 2 NSs for Escherichia coli could be over 99.99% after simulated sunlight irradiation for only 30 min. This study opens up a new path for sensible design of ternary heterostructure photocatalyst with continuous charge steps towards an extraordinary photocatalytic activity. [ABSTRACT FROM AUTHOR]

The long-range transfer of photoinduced charge-carriers was realized in the well-designed all 2D-layered heterojunction photocatalyst, which led to remarkable enhancements of both photocatalytic oxidation and reduction activities. [Display omitted] • A photo-assisted self-assembly strategy for making 2D heterojunction photocatalysts. • The novel 2D heterojunction photocatalyst is made of 2D-layered SnS 2 , RGO, and g-C 3 N 4. • An interesting long-range spatial separation of charge-carriers is realized. • The 2D heterojunction photocatalyst exhibits the enhanced photocatalytic redox ability. Constructing heterojunction photocatalysts has been proven as an ingenious tactic to adjust the lifetimes of the higher redox-active charge-carriers toward highly-efficient photocatalytic applications. Numerous recent efforts focused on the short-range spatial separation of charge-carriers in the heterojunction photocatalysts. However, engineering a long-range transfer channel in the well-designed heterojunction photocatalyst to further spatially separate the charge-carriers is still a huge challenge. In this contribution, we developed a facile photo-assisted self-assembly strategy to synthesize the all 2D-layered heterojunction photocatalysts of SnS 2 /RGO/g-C 3 N 4 nanosheets (NSs). During the synthesis process, the precursor of 2D graphene-oxide (GO) NSs was converted into the reduced GO (RGO) NSs by the photoactive semiconductors of 2D SnS 2 and g-C 3 N 4 NSs. Meanwhile, the above two 2D semiconductors were simultaneously anchored onto the surface of the RGO NSs. Upon visible-light irradiation of the synthesized SnS 2 /RGO/g-C 3 N 4 NSs, the 2D RGO component could provide a broad electron-transfer surface for the long-range spatial-separation of charge-carriers in the semiconductor components of the NSs. Thus, this all 2D-layered heterojunction photocatalyst exhibited ∼ 9.2 and ∼ 4.6-fold enhancement on the photocatalytic oxidation degradation of the organic dye, and ∼ 68 and ∼ 3.4-fold enhancement on photocatalytic protons reduction as compared to the pure SnS 2 and g-C 3 N 4 NSs, respectively. [ABSTRACT FROM AUTHOR]

• TiO 2 was synthesized by a solvothermal method and treated with N-plasma at atmospheric pressure. • Ti3+ ions of N-TiO 2 form the Ti3+ self-doped system, which causing the light absorption range enhanced. • The catalytic H 2 evolution of N-TiO 2 is 14.85 times higher than that of the pristine TiO 2 NFs. [Display omitted] The N-TiO 2 was prepared by N-plasma treatment at room temperature and ambient, which caused the results of higher generation of oxygen vacancy. The reaction also resulted in reducing more Ti3+, and forming the Ti3+ self-doped system, changing the electronic structure of Ti3+, enhancing its light absorption range, and then enhancing its photocatalytic activity. The photocatalytic activity was ~14.85 times higher than that of the pristine TiO 2. An enhancement of the photocatalytic activity of Titanium dioxide nanosheets (TiO 2 NFs) by N 2 plasma (N-plasma) treatment has been suggested. TiO 2 NFs was synthesized by a solvothermal method and treated with N-plasma at atmospheric pressure. Then the as-prepared TiO 2 and N-plasma treated TiO 2 (N-TiO 2) NFs photocatalyst were extensively characterized. Interestingly, more oxygen vacancy and Ti3+ ions were found in the N-TiO 2 NFs. Meanwhile, Ti3+ ions form the Ti3+ self-doped system, which causing the light absorption range enhanced. The catalytic H 2 evolution of N-TiO 2 NFs at a rate of 8.1 mmol g−1 h−1, which is 14.85 times higher than that of the pristine TiO 2 NFs. These results might suggest new views for the photoactivity of TiO 2 NFs and provide a kind of feasibility for other metal oxides in the photocatalytic field. [ABSTRACT FROM AUTHOR]

• 2D multi-hetero-interface was constructed in Ti 3 C 2 T x /(001)TiO 2 /C 3 N 4 nanosheets. • Ti 3 C 2 T x /(001)TiO 2 /C 3 N 4 nanosheets were produced by the in-situ oxidation/electrostatic self-assembly strategy. • Broad electron-transfer channels in the 2D multi-hetero-interface enhance the charge separation and utilization. • Photocatalytic activities of H 2 generation and CO 2 reduction were remarkably enhanced. The hetero-interface quality and area in the semiconductor heterostructure are important to the photocatalytic performance of the heterostructure. The 2D hetero-interface between two 2D semiconductors has been widely proved to enhance the photocatalytic performance, because the larger contact area of the hetero-interface can effectively improve the charge separation behavior. However, engineering high-quality 2D multi-hetero-interface in the well-designed semiconductor composite to further enhance the charge separation and utilization is still a big challenge. Herein, we constructed the 2D multi-hetero-interface in the well-designed nanosheet (NS) composite photocatalyst through an in-situ oxidation treatment combined with the electrostatic self-assembly strategy. The negatively-charged binary Ti 3 C 2 T x /(001)TiO 2 heterojunction NSs with the intimate 2D contact interface was fabricated through a facile in-situ oxidation method, while the protonated g-C 3 N 4 NSs were positively charged. Thus, the spontaneous electrostatic attraction behavior between the above opposite-charged materials of the Ti 3 C 2 T x /(001)TiO 2 heterojunction and the g-C 3 N 4 NSs enables the 2D multi-hetero-interface to be constructed in the Ti 3 C 2 T x /(001)TiO 2 /C 3 N 4 NSs. As such, the 2D multi-hetero-interface offers broad electron-transfer channels to enhance the charge separation and utilization. Upon simulated sunlight irradiation, the optimal Ti 3 C 2 T x /(001)TiO 2 /C 3 N 4 NSs achieved about 4-fold enhancement on the photocatalytic H 2 generation and 3-fold improvement on the photocatalytic CO 2 reduction as compared to the pure (001)TiO 2 or g-C 3 N 4 NSs. [ABSTRACT FROM AUTHOR]

Amine-functionalization of TiO2 nanoparticles, through a solvothermal approach, substantially increases the affinity of CO2 on TiO2 surfaces through chemisorption. This chemisorption allows for more effective activation of CO2 and charge transfer from excited TiO2, and significantly enhances the photocatalytic rate of CO2 reduction into methane and CO. [ABSTRACT FROM AUTHOR]