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In this paper, ultra-thin nanofiber PDI was obtained by self-assembly dispersion of commercial PDINH. A novel Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material was constructed by a simple solvothermal method. XRD, SEM, TEM, FT-IR and other characterization techniques proved the successful preparation of the Co/Ni-MOF-74@PDI Z-scheme heterojunction photocatalyst material. By degrading chlortetracycline hydrochloride, it was found that the photocatalytic activity of Co/Ni-MOF-74@PDI was much higher than that of pure Co/Ni-MOF-74 and PDI. Subsequently, Co/Ni-MOF-74@PDI was used to activate H2O2 to further improve the degradation efficiency of chlortetracycline hydrochloride. It was found that the photocatalytic performance was greatly improved after the addition of 19.6 mM H2O2 to the system, and the degradation rate of chlortetracycline hydrochloride was 87% within 90 min. The electron transfer pathway and H2O2 activation mechanism of the Co/Ni-MOF-74@PDI composite photocatalyst were proved by free radical quenching experiments, electron paramagnetic resonance analysis and X-ray electron spectroscopy. Finally, the easy exfoliation point and degradation pathway of chlortetracycline hydrochloride were studied using density functional theory, UPLC-MS and toxicity evaluation software. It was found that the main active substances were h+, ˙O2, 1O2 and ˙OH, and the toxicity of chlortetracycline hydrochloride and its intermediates was evaluated. [ABSTRACT FROM AUTHOR]

FeWO4 was synthesized by a simple solvothermal method. The band structure of FeWO4 was investigated on the basis of density functional theory calculations. The FeWO4 photocatalyst showed lower photocatalytic activity for the degradation of doxycycline hydrochloride under visible light irradiation. Kinetic studies using radical scavenger technologies suggested that hydroxyl radicals were the dominant photo-oxidants. In order to enhance the photocatalytic activity of FeWO4, FeWO4 was used to activate peroxymonosulfate to degrade doxycycline hydrochloride under visible light irradiation. The influences of the peroxymonosulfate dosage, doxycycline hydrochloride concentration, inorganic anions, natural organic matter and pH value on activating peroxymonosulfate to degrade doxycycline hydrochloride were investigated in detail. The mechanism of FeWO4 activating peroxymonosulfate was proposed and proved by radical quenching experiments, electron spin resonance analysis, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, transient photocurrent responses and cyclic voltammetry. It can be found that the combined activation effects of photo-generated electrons and transition metals on peroxymonosulfate to produce sulfate radicals could enhance the degradation efficiency obviously. [ABSTRACT FROM AUTHOR]

MIL-53Fe was prepared by a simple solvothermal method, and the MIL-53Fe photocatalysts showed low photocatalytic activity for the degradation of tetracycline hydrochloride under visible light irradiation. After combination with TiO2, the photocatalytic activity of MIL-53Fe was enhanced obviously. The enhanced photocatalytic activity of the MIL-53Fe@TiO2 photocatalysts could be attributed to the effective separation of the photogenerated e−/h+ pairs. In order to further enhance the degradation efficiency of MIL-53Fe@TiO2, it was used to activate peroxymonosulfate to degrade tetracycline hydrochloride. The influencing factors on the activation of peroxymonosulfate to degrade tetracycline hydrochloride were investigated in detail. The mechanism of MIL-53Fe@TiO2 activation of peroxymonosulfate was investigated by radical quenching experiments, which proved that holes and sulfate radicals controlled the degradation of tetracycline hydrochloride. Cycle experiments showed that the photodegradation efficiency did not change obviously after the catalyst was recycled three times. This study provided a new way that the synergetic effect of photocatalysis and peroxymonosulfate activation by transition metal was used for efficient photocatalytic degradation in the field of antibiotic removal, hoping to provide new ideas for the development of metal–organic frameworks. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel dual p-n junction photocatalyst called NiWO 4 /CdS/ZIF-67 was synthesized. • Persulfate was activated by photogenerated electrons, Ni and Co. • •SO 4 − were the main active substances. There was no report about dual p-n junction photocatalyst activating persulfate to accelerate the photodegradation of organic pollutants until now. Therefore, there was a need to investigate dual p-n junction photocatalyst activating persulfate to accelerate photodegradation. In this paper, we synthesized a dual p-n junction photocatalyst, NiWO 4 /CdS/ZIF-67, which demonstrated superior degradation capabilities for doxycycline hydrochloride compared to pure NiWO 4 , ZIF-67 and NiWO 4 /CdS. NiWO 4 exhibited p-type semiconductor properties, while CdS and ZIF-67 exhibited n-type semiconductor properties. By combining them into a composite photocatalyst, a conventional type II heterojunction formed at the interface of the p-n junction. This design established an internal electric field at both ends, effectively separating the photogenerated electrons and holes of each individual photocatalyst. Consequently, the photocatalytic activities of the materials were maximized. To further enhance the degradation of doxycycline hydrochloride, we employed NiWO 4 /CdS/ZIF-67 to activate persulfate under visible light irradiation. The results showed that the best degradation was achieved when 0.3 mmol persulfate was added with a k-value of 0.00681 min−1. We investigated the mechanism of activation of persulfate and the degradation pathway of doxycycline hydrochloride over the dual p-n heterojunction NiWO 4 /CdS/ZIF-67 catalysts. Additionally, we evaluated the toxicity of doxycycline hydrochloride and its intermediates using toxicity evaluation software. [ABSTRACT FROM AUTHOR]

Fe2(MoO4)3 photocatalysts were synthesized by a simple hydrothermal method. Fe2(MoO4)3 photocatalysts showed lower photocatalytic activity for the degradation of methylene blue under visible light irradiation. After compositing with g-C3N4, the photocatalytic activity of Fe2(MoO4)3 was enhanced obviously. The enhanced photocatalytic activity of the g-C3N4/Fe2(MoO4)3 photocatalysts could be attributed to the effective separation of the photogenerated e−/h+ pairs. In order to further enhance the degradation efficiency of g-C3N4/Fe2(MoO4)3, g-C3N4/Fe2(MoO4)3 was used to double activate peroxymonosulfate to degrade methylene blue. The influences of peroxymonosulfate dosage, pH value, inorganic anions and methylene blue concentration on double activating peroxymonosulfate to degrade methylene blue were investigated in detail. The mechanism of g-C3N4/Fe2(MoO4)3 double activating peroxymonosulfate was proved by radical quenching experiments, which proved that SO4˙− dominated the degradation of methylene blue. [ABSTRACT FROM AUTHOR]

Solar-to-hydrogen conversion from water splitting have received a great of interest because it can alleviate the serious environmental pollution and energy crisis. The KNbO3 photocatalyst with high conduction band and excellent anticorrosion has been reported for water splitting, but the large band gap and low separation efficiency of electron–hole pairs restrict its photocatalytic activity. In this work, the CoO/KNbO3 p-n heterojunction photocatalysts were prepared via a hydrothermal and calcination method, which exhibits excellent photocatalytic for H2 production with high rates at 144.36 μmol h−1 g−1 under simulated sunlight and 76.78 μmol h−1 g−1 under visible light irradiation (λ > 420 nm). The enhanced H2 production was ascribed to the improvement of visible light absorption and the efficient charge separation after the formation of CoO/KNbO3 p-n heterojunction, which was evidenced by the UV–vis diffuse spectra and transient photocurrent. Finally, a possible mechanism was proposed for the CoO/KNbO3 p-n heterojunction photocatalysts toward the photocatalytic activity of H2 production. This kind of CoO/KNbO3 p-n heterojunction photocatalysts can provide a reference for developing high-efficiency KNbO3-based photocatalysts. [ABSTRACT FROM AUTHOR]

Bi2WO6/Bi2MoO6 heterostructured photocatalys had been synthesized by a refluxing method. And the photocatalytic activity of Bi2WO6/Bi2MoO6 heterostructured photocatalysts was better than Bi2WO6. The enhancement in photocatalysis activity belonged to the match of energy level between the Bi2MoO6 and Bi2WO6. In order to further enhance the photocatalytic activity of Bi2WO6/Bi2MoO6, Bi2WO6/Bi2MoO6 was used to activate peroxymonosulfate to photodegradate methylene blue. The mechanism of activating peroxymonosulfate was proved by radical quenching experiment which revealed that sulfate radicals governed the removal of methylene blue. [ABSTRACT FROM AUTHOR]

Development of highly efficient and metal‐free photocatalysts for bacterial inactivation under natural light is a major challenge in photocatalytic antibiosis. Herein, we developed an acidizing solvent‐thermal approach for inserting a non‐conjugated ethylenediamine segment into the conjugated planes of 3,4,9,10‐perylene tetracarboxylic anhydride to generate a photocatalyst containing segregated π‐conjugation units (EDA‐PTCDA). Under natural light, EDA‐PTCDA achieved 99.9 % inactivation of Escherichia coli and Staphylococcus aureus (60 and 45 min), which is the highest efficiency among all the natural light antibacterial reports. The difference in the surface potential and excited charge density corroborated the possibility of a built‐in electron‐trap effect of the non‐conjugated segments of EDA‐PTCDA, thus forming a highly active EDA‐PTDA/bacteria interface. In addition, EDA‐PTCDA exhibited negligible toxicity and damage to normal tissue cells. This catalyst provides a new opportunity for photocatalytic antibiosis under natural light conditions. [ABSTRACT FROM AUTHOR]

Development of highly efficient and metal‐free photocatalysts for bacterial inactivation under natural light is a major challenge in photocatalytic antibiosis. Herein, we developed an acidizing solvent‐thermal approach for inserting a non‐conjugated ethylenediamine segment into the conjugated planes of 3,4,9,10‐perylene tetracarboxylic anhydride to generate a photocatalyst containing segregated π‐conjugation units (EDA‐PTCDA). Under natural light, EDA‐PTCDA achieved 99.9 % inactivation of Escherichia coli and Staphylococcus aureus (60 and 45 min), which is the highest efficiency among all the natural light antibacterial reports. The difference in the surface potential and excited charge density corroborated the possibility of a built‐in electron‐trap effect of the non‐conjugated segments of EDA‐PTCDA, thus forming a highly active EDA‐PTDA/bacteria interface. In addition, EDA‐PTCDA exhibited negligible toxicity and damage to normal tissue cells. This catalyst provides a new opportunity for photocatalytic antibiosis under natural light conditions. [ABSTRACT FROM AUTHOR]

Bi2WO6 nanosheets were synthesized by a hydrothermal method with H2WO4 for the first time. The band structure of Bi2WO6 was investigated on the basis of density functional theory calculations. Bi2WO6 photocatalysts showed photocatalytic activity for the degradation of methylene blue under visible light irradiation. Kinetic studies using radical scavenger technologies suggested that holes were the dominant photo-oxidants. After hybridization with C3N4, the photocatalytic activity of Bi2WO6 was obviously enhanced. The enhanced photocatalytic activity of the C3N4/Bi2WO6 photocatalysts could be attributed to the effective separation of photogenerated e−/h+ pairs. The photogenerated holes on the valence band of Bi2WO6 can transfer to the highest occupied molecular orbital of C3N4via the well-developed interface, causing a reduction in the probability of e−/h+ recombination; consequently, large numbers of photogenerated holes led to the enhancement of the photocatalytic activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co/Mn-MOF-74@g-C 3 N 4 photocatalyst was synthesized by solvothermal method. • Peroxymonosulfate was activated by photogenerated e−, Co and Mn. • SO 4 •−, 1O 2 , •O 2 and h+ mainly control the degradation of doxycycline hydrochloride. A new Z-type heterojunction photocatalytic material Co/Mn-MOF-74@g-C 3 N 4 was prepared by a simple solvothermal method. Co/Mn-MOF-74@g-C 3 N 4 was found to have a much higher photocatalytic activity than simple Co/Mn-MOF-74 due to the formation of Z-scheme heterojunction, which inhibited the recombination of photogenerated electrons and holes. Photocatalytic activity was further enhanced by activating peroxymonosulfate with Co/Mn-MOF-74@g-C 3 N 4. The removal rate of doxycycline hydrochlorid was 94 % within 60 min after adding 0.5 mmol peroxymonosulfate in the system. Furthermore, XPS, EPR and radical quenching experiments were used to demonstrate the electron transfer of Co/Mn (II) and Co/Mn (III) in Co/Mn-MOF-74 and peroxymonosulfate activation mechanism for enhanced photocatalytic performance. The possible vulnerable sites and degradation pathways of doxycycline hydrochlorid by Co/Mn-MOF-74@g-C 3 N 4 were studied by density functional theory and UPLC-MS. Toxicity Estimation Software predicted that the degradation processes of doxycycline hydrochloride could gradually reduce toxicity. This study could provide an efficient and green method for the subsequent treatment of antibiotic wastewater. [ABSTRACT FROM AUTHOR]

Unraveling how mid-gap state energy level of graphitic carbon nitride (g-C 3 N 4) promote near-infrared (NIR) driven photochemical energy conversion at the molecular level remains a grand challenge. Here, we report a series of S double-site-doped ultrathin g-C 3 N 4 nanosheets (SUCN) with adjustable intermediate band gap benefits from light response over NIR region. The SUCN produced after optimizing S double-site doping can effectively generate hydrogen (H 2) under NIR-light irradiation. The highest H 2 generation rate achieved was respectively 9.35 and 17.46 μmol g−1 h−1 under λ = 765 and λ > 800 nm, which is firstly expended photocatalytic activity of S-doped g-C 3 N 4 to NIR region beyond λ > 765 nm. We proposed a molecular-level method, i.e., the localized oxidation state of proton acceptor triethanolamine (TEOA) in the mid-gap state to ensure the NIR-driven H 2 generating behavior. [Display omitted] • g-C 3 N 4 was doped with S atoms at a specific site of the triazine skeleton. • S doping provides an adjustable intermediate band gap of g-C 3 N 4. • The 0.36-SUCN obtained 43 times higher PHE than g-C 3 N 4. • The S-doped g-C 3 N 4 firstly realized PHE in the near-infrared region. • The NIR-driven H 2 generation was firstly demonstrated by a molecular-level method. [ABSTRACT FROM AUTHOR]

The development of Z-scheme heterojunction photocatalytic systems is a promising strategy to produce hydrogen and for pollutant degradation. In this study, the direct Z-scheme CdS/Bi4V2O11 photocatalysts were synthesized via a two-step solvothermal method. The photocatalytic properties of the samples were measured by ciprofloxacin (CIP), tetracycline (TC) and rhodamine B (RhB) degradation under visible light (λ ＞ 420 nm). In addition, a probable reaction mechanism for organic pollutants over CdS/Bi4V2O11 photocatalysts was also proposed based on the analysis of electron spin resonance (ESR) and active species capture experiments. The enhanced photocatalytic activity of CdS/Bi4V2O11 photocatalysts was ascribed to the efficient electron transfer of direct Z-scheme CdS/Bi4V2O11 photocatalysts. [ABSTRACT FROM AUTHOR]

The MIL-53Fe@g-C 3 N 4 samples were prepared by solvothermal method and recorded as CM-x. The potocatalytic activity of the MIL-53Fe@g-C 3 N 4 was significantly higher than MIL-53Fe, and it might be due to the successfully constructed heterojunction promoting the migration and separation effciency of photo-generated electron and hole pairs. In order to further enhance the potocatalytic activity of the MIL-53Fe@g-C 3 N 4 , peroxymonosulfate was introduced into the MIL-53Fe@g-C 3 N 4 /Vis system, and the peroxymonosulfate could be simultaneously activated by photogenerated electron and iron to form sulfate radical under visible light irradiation. Therefore, the degradation efficiency of oxytetracycline hydrochloride was enhanced obviously. Meantime, the effects of peroxymonosulfate dosage, oxytetracycline hydrochloride concentration, temperature and pH on the degradation efficiency of oxytetracycline hydrochloride were studied systematically. Meanwhile, the free radical catching experiments and electron spin resonance analysis confirmed that the main active substances were sulfate radical and hole. Finally, the mechanism and possible degradation pathways of MIL-53Fe@g-C 3 N 4 activating peroxymonosulfate to degrade oxytetracycline hydrochloride were proposed. [Display omitted] • MIL-53Fe@g-C 3 N 4 photocatalysts was synthesized by solvothermal method. • Peroxymonosulfate was activated by photogenerated e− and Fe. • The SO 4 •− and •OH mainly contributed to oxytetracycline hydrochloride degradation. [ABSTRACT FROM AUTHOR]

Two-dimensional g-C 3 N 4 /Bi 2 WO 6 heterojunction photocatalysts have been successfully synthesized by a multi-step method. Based on the structure and morphology characterization, the as-prepared photocatalysts exhibited a nanosheet/nanosheet hybrid structure, which could provide a large heterogeneous surface area, increase the transmission route of photo-induced carriers and then suppress the charge recombination. To investigate the practical photocatalytic performance for water purification of these heterojunction photocatalysts, organic dyes such as Rhodamine B (RhB) and antibiotics including tetracycline (TC) and ciprofloxacin (CIP) have been selected as the target pollution under visible-light irradiation. The optimum photocatalyst (the weight ratio of g-C 3 N 4 to Bi 2 WO 6 is 1:0.67) was more than three times and two times than pure g-C 3 N 4 and Bi 2 WO 6 , respectively. The enhanced photocatalytic activities of g-C 3 N 4 /Bi 2 WO 6 heterojunction photocatalysts might be ascribed to the two-dimensional structure. In combination of the experiment results, the possible photo-induced charge transfer route has been detailed illustrated. [ABSTRACT FROM AUTHOR]

Well-defined m -BiVO 4 dendrites have been synthesized using a simple hydrothermal method without adding organic surfactant. A series of time-dependent experiments were conducted to investigate the shape formation mechanism of the m -BiVO 4 dendrites. Furthermore, the corresponding growth mechanism which involved the Ostwald ripening process has been discussed. The m -BiVO 4 dendrites showed great enhanced activity in the visible-light photocatalytic degradation of Rhodamine B (RhB) solution which might be attributed to the special morphology. [ABSTRACT FROM AUTHOR]

• The Schottky junctions comprising of pd and HNb 3 O 8 NS with oxygen vacancies is prepared. • The Schottky junction accelerates the separation and transfer of charge carriers. • Fast charge transfer benefits the accumulation of electrons on Pd active sites. • The Pd/HNb 3 O 8 -V O NS exhibit superior photocatalytic CO 2 reduction towards CH 4. Photocatalytic conversion of CO 2 into CH 4 is severely hampered by the kinetically challenging eight-electron transfer process. Herein, a hybrid photocatalyst comprising Pd nanoparticles-decorated HNb 3 O 8 nanosheets with surface oxygen vacancies (Pd/HNb 3 O 8 -V O NS) is designed by a simple light-induced hydrogenation strategy. In this design, the introduction of V O is beneficial to the formation of defect energy level within the band gap of HNb 3 O 8 -V O NS, which could enhance the visible light absorption efficiency. Meanwhile, the constructed Schottky junction between the Pd nanoparticle and HNb 3 O 8 -V O NS accelerates the migration of photogenerated charge from HNb 3 O 8 -V O NS to Pd, thus improving the photocatalytic performance of CO 2 reduction. The experimental results of photocatalytic CO 2 reduction showed that the optimal Pd/HNb 3 O 8 -V O NS (0.5% Pd/HNb 3 O 8 -V O NS) exhibits a high CH 4 production yield of 288.4 μmol·g‒1 with 98.9% selectivity. This CH 4 production yield is 37.9, 39.5, and 7.2 times higher than the bare HNb 3 O 8 NS, HNb 3 O 8 -V O NS, and 0.5% Pd/HNb 3 O 8 NS, respectively. This work provides a novel light on rationally fabricating high-activity and high-selectivity photocatalysts through integrating Schottky junction and defect engineering design. [Display omitted] [ABSTRACT FROM AUTHOR]

By skillfully introducing a conjugate electron donating ring into the g-C 3 N 4 framework, the as-prepared 3 wt% PPD/CN sample not only narrows the bandgap of g-C 3 N 4 , but also absorbs more solar light up to 600 nm. As a result, the optimal sample exhibited hydrogen escape under orange light (600 nm) and bare g-C 3 N 4 had almost no such performance. [Display omitted] • Benzene ring doping in the specific site of the network of g-C 3 N 4 was obtained. • It still has photoactivity that g-C 3 N 4 barely has under the orange light. • The 3 wt% PPD/CN can effectively cover more sufficient photo flux (λ = 600 nm). • The benzene ring incorporation of g-C 3 N 4 enhanced photogenerated carrier separating. Grafting π-conjugated donor units into graphitic carbon nitride (g-C 3 N 4) represents a promising alterative to improve its light absorption range and charge transfer kinetics. To this end, we here report an efficient intramolecular g-C 3 N 4 -based conjugated copolymers via the one-spot thermal copolymerization for not only reduces the bandgap to 2.56 eV and thus expand the visible-light harvesting capability, but also accelerates the separation ability of photogenerated excitons. Consequently, the copolymer of 3 wt% p-phenylenediamine with melamine exhibits extraordinary hydrogen (H 2) evolution rate of 1040 μmol g−1 h−1 under visible light. Interestingly, it still shows hydrogen production (5.29 μmol g−1 h−1) at λ = 600 nm (orange light). Systematic characterizations have proved that the optimal sample has high photocatalytic activity, due to rapid charge transfer kinetics and exciton separation. Our work sheds light on a molecular design to regulate charge-transfer dynamics among of polymeric semiconductors towards efficient solar-to-H 2 production. [ABSTRACT FROM AUTHOR]

[Display omitted] The inherent electron localized heptazine structure of carbon nitride (CN) derived from intrinsic tertiary N (N 3C) bridging structure makes the photogenerated charge separation rather difficult, which severely limits photocatalytic CO 2 activity of CN. Therefore, modulation of N 3C bridging structure of CN is highly desirable to enhance the charge separation efficiency of CN. Herein, we reported a novel thiophene-bridged CN (BTCN) with intramolecular donor-π-acceptor (D-π-A) systems synthesized by nucleophilic substitution and Schiff base reaction to improve the photogenerated charge separation efficiency. The experimental and density functional theory (DFT) results indicate that this BTCN exhibits a high π-electron delocalization range and enhanced photogenerated charge transfer efficiency, which mainly account for the enhanced photocatalytic activity. The optimal BTCN photocatalyst exhibits enhanced charge separation efficiency and higher photocatalytic CO 2 reduction activity with a CO yield of 23.02 μmol·g−1·h−1, which was higher than those of CN and edge-modified CN (ETCN) counterpart. This work highlights the importance of regulation of π-electron delocalization for the design of highly active CN photocatalysts via the rational substitution of N 3C bridging structure with π-spacer molecular linkages for photocatalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Mo 2 C can be used as a cocatalyst for photocatalytic hydrogen evolution over K+Ca 2 Nb 3 O 10 − nanosheets. • The Mo 2 C/K+Ca 2 Nb 3 O 10 − heterojunction showed enhanced photocatalytic H 2 evolution activity. • The improved charge separation and transfer contributes to the enhanced catalytic activity. Developing low cost and highly efficient catalysts for photocatalytic hydrogen (H 2) evolution reaction holds significant function in water splitting. The co-catalysts load on semiconductor can promote the rapid separation and migration of photon-generated carriers, active interfacial reaction and suppress photocorrosion. Herein, we report the synthesis of Mo 2 C nanoparticles (NPs) decorated K+Ca 2 Nb 3 O 10 − nanosheets (K+CNO− NSs) heterojunction photocatalyst, where the Mo 2 C is used as a co-catalyst. The optimal Mo 2 C/K+CNO− sample with a Mo 2 C loading amount of 3 wt% yields an enhanced H 2 production rate of 686.5 μmol g‒1, which is about 8.8 times higher than that of bare K+CNO‒ NSs (78.1 μmol g‒1). The enhanced photocatalytic activity might be ascribed to the faster photoinduced electrons transfer due to the ultrathin structure of K+CNO− NSs and effective charge carrier separation derived from the abundant contact heterointerfaces between K+CNO− NSs and Mo 2 C NPs. This study provides a guidance to construct efficient non-noble metal co-catalyst for photocatalytic H 2 evolution from water splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] Photo-chemical conversion of CO 2 into solar fuels by photocatalysts is a promising and sustainable strategy in response to the ever-increasing environmental problems and imminent energy crisis. However, it is unavoidably impeded by the insufficient active site, undesirable inert charge transfer and fast recombination of photogenerated charge carriers on semiconductor photocatalysts. In this work, all these challenges are overcome by construction of a novel defect-engineered Z-scheme hybrid photocatalyst, which is comprised of three-dimensional (3D) BiOBr nanoflowers assembled by nanosheets with abundant oxygen vacancies (BiOBr-V O) and two-dimensional (2D) HNb 3 O 8 nanosheets (HNb 3 O 8 NS). The special 3D-2D architecture structure is beneficial to preventing photocatalyst stacking and providing more active sites, and the introduced oxygen vacancies not only broaden the light absorption range but also enhance the electrical conductivity. More importantly, the constructed Z-scheme photocatalytic system could accelerate the charge carriers transfer and separation. As a result, the optimal BiOBr-V O /HNb 3 O 8 NS (50%-BiOBr-V O /HNb 3 O 8 NS) shows a high CO production yield of 164.6 μmol·g−1 with the selectivity achieves to 98.7% in a mild gas-solid system using water as electron donors. Moreover, the BiOBr-V O /HNb 3 O 8 NS photocatalyst keeps high photocatalytic activity after five cycles under the identical experimental conditions, demonstrating its excellent long-term durability. This work provided an original strategy to design a new hybrid structure photocatalyst involved V O s, thus guiding a new way to further enhance CO 2 reduction activity of photocatalyst. [ABSTRACT FROM AUTHOR]

Graphite-like carbon nitride (g-C 3 N 4) has been regarded as a promising photocatalyst for solar-to-chemical conversion. Nevertheless, the narrow absorption of light extremely limited its photocatalytic performance under near-infrared (NIR) irradiation. Herein, the Cu 7. 2 S 4 with outstanding NIR absorption was successfully introduced to g-C 3 N 4 nanosheets through a simple in-situ growth procedure. As expected, the constructed Cu 7.2 S 4 /g-C 3 N 4 (CSCN) photocatalysts exhibit superior H 2 production activity of 82 μmol g−1 h−1 under NIR light irradiation (λ > 800 nm), which outperforms currently reported g–C 3 N 4 –based NIR-driven H 2 production systems. Especially, the optimal sample CSCN-5 displays a robust activity of 66 μmol g−1 h−1 at λ = 850 nm monochromatic light irradiation. The excellent photocatalytic performance is linked to the extended optical absorption as well as the efficient separation efficiency of photoinduced carriers, which are evidenced by the UV-visible absorption spectroscopy and photoelectrochemical test. This work provides an effective approach for constructing a Cu 7.2 S 4 /g-C 3 N 4 photocatalytic system for the transformation of NIR solar energy into hydrogen. The novel NIR-driven Cu 7. 2 S 4 /g-C 3 N 4 composite photocatalyst was constructed through a convenient in situ growth process. As expected, the outstanding photocatalytic H 2 yield was 82 μmol g−1 h−1 under the irradiation of NIR light (λ > 800 nm), which outperforms currently reported g–C 3 N 4 –based NIR-driven H 2 production systems. More significantly, the sample CSCN-5 shows an optimum activity (66 μmol g−1 h−1) under λ = 850 nm monochromatic light irradiation. This work provides a feasible approach for achieving g–C 3 N 4 –based photocatalyst NIR-induced superior solar-to-chemical conversion. [Display omitted] • Cu 7·2 S 4 modified g-C 3 N 4 is prepared by a facile hydrothermal treatment method. • The Cu 7·2 S 4 /g-C 3 N 4 composites show a superior optical adsorption from visible to NIR. • The Cu 7·2 S 4 /g–C 3 N 4 –5 composite exhibits excellent HER of 82 μmol g−1 h−1 (λ > 800 nm). • The HER of Cu 7·2 S 4 /g–C 3 N 4 –5 shows no obvious change after 4 runs within 20 h. [ABSTRACT FROM AUTHOR]

In this work, a high-performance composite photocatalyst composed of WO3 nanosheets and Bi24O31Br10 nanosheets was successfully synthesized. The photocatalytic activity of the obtained samples was studied by the degradation of tetracycline hydrochloride under visible light irradiation. The results showed that Bi24O31Br10 modified with the appropriate amount of WO3 nanosheet exhibits higher catalytic activity and stability during the photocatalytic processes, and the holes (h+) is involved in the photolysis reaction as the main active species. The crystallization, morphology, optical and electrochemical properties of the as-prepared composite photocatalyst were characterized, and the mechanism of high photocatalytic activity was also explored. The optimal sample (10%-WO3/Bi24O31Br10) exhibited the best performance for tetracycline hydrochloride (TC) degradation, and more than 80% of the TC was degraded after 60 min under light irradiation. The degradation rate constant k was about 3.34-fold and 1.54-fold higher than pure WO3 and Bi24O31Br10, respectively. Its high photocatalytic performance can be attributed to the following reasons: the appropriate conduction band and valence band positions between WO3 and Bi24O31Br10, the close contact between the two visible light-driven photocatalysts, and the effective separation of the spatial charge. Our work may help to further expand the potential application of oxygen-rich bismuth oxyhalides photocatalyst in wastewater treatment, and provide a new strategy for the modification of nanostructured photocatalysts. [ABSTRACT FROM AUTHOR]

A Bi/HNb 3 O 8 -Vo hybrid photocatalyst was designed by a simple two-step method. Through the synergistic effect of oxygen vacancies and Bi nanoparticles on the catalyst surface, the electron-hole complexation rate was reduced, and the adsorption and activation of N 2 was enhanced. [Display omitted] Due to the high stability of the N 2 molecule and the low charge separation efficiency, the photocatalytic reduction of N 2 to high-value chemicals (NH 3) under mild conditions remains a great challenge. Herein, a composite photocatalyst (Bi/HNb 3 O 8 -Vo nanosheets) with Bi nanoparticles modified the HNb 3 O 8 -Vo nanosheets are designed for the conversion of N 2 into NH 3. In this design, the introduction of oxygen vacancies on the catalyst surface facilitates the formation of defective energy levels within the band gap of HNb 3 O 8 -Vo NS, which promotes the absorption of visible light, and enhances the charge carrier transport and separation. Bi nanoparticles co-catalyst not only facilitates the separation and migration of photogenerated charges, but also acts as reaction sites to adsorb and activate N 2 molecule. Consequently, the optimized 5 % Bi/HNb 3 O 8 -Vo photocatalysts show a NH 3 yield of 372.7 μmol/L g−1h−1 under full spectral irradiation without sacrificial agent, which is much higher than that of HNb 3 O 8 NS (92.2 μmol/L g−1h−1). This work provides a new way for the design of efficient N 2 reduction photocatalysts through the synergistic effect of surface vacancies and metal co-catalysts. [ABSTRACT FROM AUTHOR]

A Bi/HNb 3 O 8 -Vo hybrid photocatalyst was designed by a simple two-step method. Through the synergistic effect of oxygen vacancies and Bi nanoparticles on the catalyst surface, the electron-hole complexation rate was reduced, and the adsorption and activation of N 2 was enhanced. [Display omitted] Due to the high stability of the N 2 molecule and the low charge separation efficiency, the photocatalytic reduction of N 2 to high-value chemicals (NH 3) under mild conditions remains a great challenge. Herein, a composite photocatalyst (Bi/HNb 3 O 8 -Vo nanosheets) with Bi nanoparticles modified the HNb 3 O 8 -Vo nanosheets are designed for the conversion of N 2 into NH 3. In this design, the introduction of oxygen vacancies on the catalyst surface facilitates the formation of defective energy levels within the band gap of HNb 3 O 8 -Vo NS, which promotes the absorption of visible light, and enhances the charge carrier transport and separation. Bi nanoparticles co-catalyst not only facilitates the separation and migration of photogenerated charges, but also acts as reaction sites to adsorb and activate N 2 molecule. Consequently, the optimized 5 % Bi/HNb 3 O 8 -Vo photocatalysts show a NH 3 yield of 372.7 μmol/L g−1h−1 under full spectral irradiation without sacrificial agent, which is much higher than that of HNb 3 O 8 NS (92.2 μmol/L g−1h−1). This work provides a new way for the design of efficient N 2 reduction photocatalysts through the synergistic effect of surface vacancies and metal co-catalysts. [ABSTRACT FROM AUTHOR]

MFeO3 (M = La or Bi) photocatalysts were synthesized via a sol–gel process. The MFeO3 photocatalysts showed lower photocatalytic activity for the degradation of doxycycline hydrochloride under visible light irradiation. After the MFeO3 nanoparticles were loaded in the channels of SBA-15, the photocatalytic activity of MFeO3/SBA-15 was enhanced by nine and two times compared to that of pure LaFeO3 and BiFeO3, respectively. The enhanced photocatalytic activity of the MFeO3/SBA-15 photocatalysts could be attributed to their larger surface areas. In order to further enhance the degradation efficiency for doxycycline hydrochloride, MFeO3/SBA-15 was used to activate peroxymonosulfate; the Vis/MFeO3/SBA-15/PMS system showed the best activity in the degradation of doxycycline hydrochloride, which was two and three times higher than that of the Vis/LaFeO3/SBA-15 and Vis/BiFeO3/SBA-15 systems, respectively. The influences of PMS dosage, pH value, temperature, natural organic matter, inorganic anions and doxycycline hydrochloride concentration on the degradation rates were investigated in detail. The PMS activation mechanisms induced by MFeO3/SBA-15 were examined by radical quenching, electron paramagnetic resonance tracing methods and photoluminescence spectral characterization. It was found that the photogenerated e−/h+ and the Fe(III)/Fe(II) redox pairs on the surface of MFeO3/SBA-15 could synergistically activate PMS to produce sulfate radical, and the sulfate radical was the main active substance. [ABSTRACT FROM AUTHOR]

Bi2MoO6 nanoflakes are synthesized via a normal hydrothermal method. Bi2MoO6 photocatalysts show lower photocatalytic activity for the degradation of methylene blue under visible light irradiation. In order to further enhance the degradation efficiency, Bi2MoO6 is used to activate the peroxymonosulfate for the degradation of methylene blue under visible light. Bi2MoO6 nanoflakes show excellent degradation efficiency in the Bi2MoO6/Vis/peroxymonosulfate (PMS) system. Moreover, the influences of PMS dosage, pH value, and inorganic anions on photodegradation are evaluated. The mechanism of activating peroxymonosulfate is proved by radical quenching experiment, which reveals that sulfate radicals govern the removal of methylene blue. [ABSTRACT FROM AUTHOR]

By using in-site generated formate, 2D HOFs of TCPP, with excellent stability and permanent porosity (BET surface area larger than 560 m2 g−1), have been obtained. The constructed 2D square-like TCPP-HCO2 grid sheets have shown considerable in-plane stability that comparable to the TCPP-based 2D MOFs, that can be exfoliated into atomically thin 2D nanosheets with efficient photocatalytic activity in aqueous system. These results are expected to shed light on the application-orientated one-pot synthesis for new kinds of multi-dimensional HOFs. [ABSTRACT FROM AUTHOR]

Highlights: [•] Photocatalytic activity of the WO3 nanoplates is much higher than commercial WO3. [•] OH is proved the active species responsible for photocatalytic reactions over WO3. [•] The photocatalytic reaction mechanism of the WO3 nanoplates is confirmed. [•] The template-free hydrothermal route is facile, cost effective and can be scaled up. [Copyright &y& Elsevier]

[Display omitted] • Z-scheme mechanism was demonstrated by ESR characterizations. • The high photocatalytic activity is owing to the successful fabrication of Z-scheme heterojunction and efficient charge separation. • Direct Z-scheme system enhances the separation of photogenerated charge carriers. • 0D/2D Zn-AgIn 5 S 8 QDs/α-Fe 2 O 3 heterostructures exhibit the efficient photocatalytic H 2 generation. Multinary sulfide quantum dots (QDs) have exhibited outstanding advantages including large surface areas, unique optical properties and adjustable band gap, which are beneficial for visible-active photocatalysis. However, the use of QDs also brings about serious issues of charge recombination and particle agglomeration. Here, a rational design of direct 0D/2D Z-scheme heterojunction of Zn-AgIn 5 S 8 /α-Fe 2 O 3 is described. Appropriate band alignment is conducive to the construction of Z-scheme heterostructures, thus enhancing the redox ability of the semiconductors and inhibiting the charge recombination. Simultaneously, the zeta potential differences between the two semiconductors can make them achieve a close interface contact by electrostatic adsorption and then the 0D Zn-AgIn 5 S 8 (ZAIS) QDs can be dispersed uniformly on 2D α-Fe 2 O 3 nanosheets, which can reduce the agglomeration of QDs. At the same time, the advantages of large specific surface area and short electron transmission path of QDs can also be exerted. Meanwhile, α-Fe 2 O 3 nanosheets with high conductivity can rapidly lead out the photogenerated charge carriers and thus suppress the recombination of the electrons and holes in QDs. The optimum nanocomposites with 3 wt% α-Fe 2 O 3 nanosheets display a photocatalytic H 2 evolution rate of 1.7 mmol g−1 h−1, 3.5 times to that of pure QDs, with an apparent quantum efficiency of 7.48% at 450 nm. Electrochemiluminescence spectra, time-resolved photoluminescence spectra and electron spin resonance spectra further testify the enhanced charge transfer and the direct Z-scheme mechanism of the 0D/2D heterojunction. This work emphasizes the suitable band matching to adjust the exciton properties and charge transfer characteristics of QDs by constructing Z-scheme heterojunction for efficient utilization of visible light. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting for hydrogen production represents an ideal pathway for solar energy harvesting and conversion, for which narrow bandgap multinary sulfides play an important role. Here, series of Zn–AgIn 5 S 8 /g-C3N4 0D/2D nanocomposites were prepared by in-situ growth of the Zn–AgIn 5 S 8 quantum dots (QDs) on g-C3N4 nanosheets for improved charge separation. To our surprise, rather than a photoactive component, here g-C3N4 nanosheets act as a charge transfer mediator, where only a relatively low ratio is required. The as-fabricated Zn–AgIn 5 S 8 /g-C3N4 nanocomposites were systematically studied. When the mass ratio of g-C3N4 was 10%, the hydrogen production rate was maximized, which was 1.39 times higher than pure Zn–AgIn 5 S 8 QDs and 138.6 times higher than g-C3N4. The enhanced photocatalytic activity of the Zn–AgIn 5 S 8 /g-C3N4 nanocomposites is attributed to the intimate interface contact, which results in the effective separation and transfer of the photogenerated charge carriers as proved by the PL lifetime, transient photocurrent and electrochemical impedance spectra measurements. The Zn–AgIn 5 S 8 /g-C3N4 nanocomposites also exhibit excellent cycle stability. A plausible mechanism was proposed for the 0D/2D Zn–AgIn 5 S 8 /g-C3N4 composite photocatalysts. This work provides a relatively simple method for constructing high-quality 0D/2D heterostructure of QDs/nanosheets, as well as new insight for the efficiency improvement of narrow-bandgap sulfide photocatalysts. Image 1 • 0D/2D Zn–AgIn 5 S 8 /g-C 3 N 4 were prepared by a simple in-situ growth method. • Zn–AgIn 5 S 8 /g-C 3 N 4 exhibited higher H 2 production rate and longer carrier lifetime. • The g-C 3 N 4 nanosheets act as the hole transfer mediator instead of light absorber. [ABSTRACT FROM AUTHOR]

Development of the novel photocatalyst with outstanding photocatalytic activity is of huge interest for photocatalytic degradation of organic pollution using solar energy. In this work, a new photocatalyst was achieved by CdS nanoparticles decorated K + Ca 2 Nb 3 O 10 − (KCNO) nanosheets. The as-fabricated CdS/KCNO hybrids exhibited well-defined morphology and enhanced photocatalytic activity than pristine KCNO. On the basis of the physicochemical characterization and photocatalytic performance test, it is believed that the CdS nanoparticles can effectively promote the photo-induced charge separation of KCNO nanosheets, and the relative mechanism has been investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel Au/Ar-CN photocatalyst was designed for the photocatalytic CO 2 reduction. • Intramolecular modifications regulate the local π-electron distribution of CN. • The Schottky junctions modulate space charge transfer and provide CO 2 RR sites. • Au/Ar-CN performs high photocatalytic evolution CO rate of 32.03 μmol·g–1·h–1. Polymeric carbon nitride (CN) is one of the most prospective non-metallic catalysts at present, yet its photocatalytic activity is unsatisfactory mainly due to the poor intramolecular charge carrier separation efficiency originated form its special electronic structure. Herein, we demonstrate a synergistic strategy to improve the charge carriers transfer and separation efficiency of CN synchronously by extending the π-conjugated system via incorporation of O-containing aromatic ring in the CN skeleton (Ar-CN) and constructing a Schottky junction via decoration of Au nanoparticles (Au Nps). The introduced O-containing aromatic ring can create a local asymmetry, delocalize the π-conjugated system of CN, and thus promote the in-plane charge transport of CN, while the formed loading of Au Nps can further promote interlayer charge transfer efficiency of Ar-CN. The optimized 3 %Au/Ar-CN photocatalyst exhibits a high photocatalytic CO 2 activity with a CO yield of 32.03 μmol·g−1·h−1, which is higher than those of CN (2.38 μmol·g−1·h−1) and Ar-CN (6.42 μmol·g−1·h−1). This study provides a feasible co-modification strategy to enhance the charge transfer and photocatalytic activity of CN by extending the π-conjugation system and constructing Schottky junctions. [ABSTRACT FROM AUTHOR]

The artificially Z-scheme heterojunctions between WO 3 nanosheet and SnNb 2 O 6 nanosheet with strongly coupled heterointerfaces were successfully constructed via a simple hydrothermal coassembly method. Transmission electron microscopy (TEM) and high-resolution TEM proved that an intimate contact interface was formed. The synthesized heterojunctions exhibites enhanced photodegradation efficiency for Rhodamine B under irradiation of visible light, and the highest reaction rate over 30%-WO 3 /SnNb 2 O 6 nanosheet heterojunctions is about 4.7-fold and 2-fold higher than that of pristine WO 3 and SnNb 2 O 6 , respectively. Such a considerable improvement could be mainly attributed to the rapid migration of the photo-induced e − /h + pairs through the nanosheets-coupled heterojunction interfaces. A possible directly Z-scheme charge transfer mechanism was proposed for the elimination of organic contaminants under irradiation of visible light. This work may furnish new insights into development of novel 2D/2D nanosheet heterojunctions with the enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

Spatial separation of photogenerated electron-hole pairs is one of the most important factors that determine the efficiency of a photocatalyst. It is well acknowledged that the fabrication of heterogeneous photocatalysts with two different inorganic semiconductors is a good strategy to effectively improve the charge separation of electrons and holes. This study describes a novel visible light-induced g-C3N4/Bi3TaO7 composite photocatalyst with superior photocatalytic properties toward the degradation of tetracycline (TC) by visible light irradiation. The formation of heterojunctions significantly improves the separation efficiency of photogenerated carriers, which is confirmed by the photocurrent density and electrochemical impedance spectroscopy. Electron spin resonance examination and trapping experiments confirm that the photoinduced active species (ṖOH and ṖO2−) are responsible for the degradation of tetracycline. Based on the experimental results, a possible Z-scheme system reaction mechanism for the g-C3N4/Bi3TaO7 composite towards the degradation of TC under visible light was proposed. [ABSTRACT FROM AUTHOR]

Water-soluble deoxynivalenol (DON) pose a major threat as a potential organic pollutant to water environmental quality. DON is a toxic secondary metabolite produced by molds of the Fusarium genus and one of the most important mycotoxins in cereal commodities, which can be enriched from the contaminated grain by deoxynivalenol in the process of wet processing. In this work, graphene/ZnO hybrids has been successfully prepared via a simple one-step hydrothermal method and exhibited superior photocatalytic activity for the photodegradation of DON under the irradiation of UV light. The UV light photocatalytic activity of graphene/ZnO hybrid GZ0.3 was 3.1 times than pure ZnO and about 99% of DON (15 ppm) could be photodegraded within 30 min totally while there were three peaks of intermediate products appeared. The ESI/MS analysis confirmed the presence of DON and degradation product with the secondary mass spectrogram in the positive ESI mode. Overall, this work could provide new insights into the fabrication of graphene/ZnO hybrids composite as high performance photocatalysts and facilitate their application in the mycotoxin detoxification and environmental protection issues. [ABSTRACT FROM AUTHOR]

Novel visible-light-driven 2D-2D heterojunction photocatalysts was constructed based on 2D g-C 3 N 4 and exfoliated ultrathin K + Ca 2 Nb 3 O 10 − nanosheets, which is derived from Dion-Jacobson phase layer perovskites. The photocatalytic performance of the 2D-2D g-C 3 N 4 /K + Ca 2 Nb 3 O 10 − nanosheet heterojunctions was evaluated by the degradation of tetracycline hydrochloride under visible light irradiation. Compared with bare K + Ca 2 Nb 3 O 10 − and g-C 3 N 4 , the g-C 3 N 4 /K + Ca 2 Nb 3 O 10 − nanosheet heterojunctions exhibited considerably enhanced photocatalytic activity towards the degradation of tetracycline hydrochloride, which is about 6.6 and 1.8 times higher than that of pure K + Ca 2 Nb 3 O 10 − and g-C 3 N 4 , respectively. This enhanced activity can be mainly attributed to the synergistic effect of g-C 3 N 4 /K + Ca 2 Nb 3 O 10 − nanosheet heterojunctions with strong interfacial interaction and abundant 2D coupling interfaces, which could efficiently promote the photo-induced charge separation. The results of work demonstrated that construction of 2D-2D heterojunctions is an effective strategy to obtain the enhanced photocatalytic activity towards the degradation of tetracycline hydrochloride. [ABSTRACT FROM AUTHOR]

Novel visible-light-driven AgI/WO 3 nanocomposites were synthesized by a facile precipitation method. Multiple techniques were applied to investigate the structures, morphologies, optical and electronic properties and photocatalytic performance of as-prepared samples. The photocatalytic performance of the AgI/WO 3 nanocomposites was evaluated sufficiently by using colorless antibiotic agent tetracycline hydrochloride (TC). The optimum photocatalytic performance of TC photodegradation over 20%-AgI/WO 3 is as about 4.3 and 25 times high as that of pure AgI and WO 3 , respectively. The possible mechanism for the enhanced photocatalytic activity could be attributed to the formation of a redox-mediator-free direct Z-scheme system which causes the photogenerated electrons migrate from WO 3 to AgI, leading to effective charge separation of WO 3 . Furthermore, the stability and the possible mechanism of AgI/WO 3 nanocomposite photocatalysts for TC degradation are also elucidated. [ABSTRACT FROM AUTHOR]

Visible-driven photocatalysis plays a critical role in solar energy conversion, but the efficiency is limited by the poor charge separation and utilization. Here, a ternary photocatalyst is constructed using Cu-In-Zn-S quantum dots (CIZS QDs), MoS 2 and carbon dots (CDs). Interestingly, transient photovoltage measurements confirm that MoS 2 has no assistance on the charge extraction rate, whereas CDs dramatically increases the attenuation constant of the charge recombination process (from 0.178 to 0.260 ms) due to its electron sinking effect. The optimal hydrogen production rate of CIZS/MoS 2 /CDs reaches 3706 μmol g-1 h-1, which is 6.65 and 148.24 times to that of CIZS QDs and MoS 2 , respectively. Further electrocatalytic tests indicate that MoS 2 is the main place for hydrogen evolution reaction, whereas CIZS and CDs are responsible for light harvesting and charge sinking, respectively. This work provides a useful guideline for the synergy of charge extraction and utilization process in composite photocatalyst design. Carbon dots are used for mediating highly efficient charge sinking, resulting in the increase of attenuation constant of surface charge carriers from 0.178 to 0.260 ms and 6.65 times enhancement of hydrogen evolution rate in CIZS/MoS 2 /CDs. [Display omitted] • Carbon-dots-mediated highly efficient charge sinking in CIZS/MoS 2 /CDs photocatalyst for hydrogen evolution. • The hydrogen production rate over the CIZS/MoS 2 /CDs has 6.65-fold increase over primal CIZS. • The attenuation constant of the surface charge carriers in CIZS/MoS 2 /CDs increases from 0.178 to 0.260 ms. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2D/2D MgAl LDO/N v -CN photocatalysts were designed for CO 2 RR. • The catalyst exhibits superior photocatalytic CO 2 RR activity. • The catalysts achieved the CO evolution rate of 20.47 µmol·g−1·h−1. • The synergistic of defects and Lewis sites promote CO 2 photoreduction activity. Conversion of CO 2 to CO from solar energy on semiconductors is a promising route to renewable energy, but their practicality is limited by the poor adsorption and activation of CO 2 on the semiconductor surface and the low utilization of photovoltaic carriers. Here, we construct a MgAl layered double oxide/nitrogen-deficient carbon nitride (MgAl LDO/N v -CN) nanosheets hybrid by in situ deposition of MgAl layered double hydroxide (MgAl LDH) on N v -CN nanosheets followed by subsequent calcination. The MgAl LDO serves as the surface-rich Lewis basic sites to effectively enhance adsorption of CO 2 and H 2 O, while the nitrogen defects can enhance the optical absorption of g-C 3 N 4 and improve the charge carrier separation. The optimal MgAl LDO/N v -CN has high photocatalytic activity for CO 2 reduction with a CO generation rate of 20.47 µmol·g−1·h−1 under visible light illumination, which is 6 times higher than that of bulk g-C 3 N 4. Our work highlights the significance of synergy of MgAl LDO Lewis base/acid sites and nitrogen vacancy defects in the design of efficient photocatalysts for CO 2 reduction. [ABSTRACT FROM AUTHOR]

• ZnIn 2 S 4 /KCa 2 Nb 3 O 10 nanosheet heterojunctions are constructed by in-situ solution-processed method. • The optimal sample shows significantly enhanced photocatalytic CO 2 reduction activity than bare ZnIn 2 S 4 and KCa 2 Nb 3 O 10. • The enhanced photocatalytic activity is ascribed to the improved charge separation efficiency of heterojunctions. ga1 Construction of heterojunctions with face-to-face contact is an excellent strategy for highly efficient photocatalytic CO 2 reduction system. Herein, ZnIn 2 S 4 /KCa 2 Nb 3 O 10 (ZnIn 2 S 4 /KCNO) 2D/2D nanosheet heterojunctions are fabricated via an in-situ solution-processed method, and the optimal 20%-ZnIn 2 S 4 /KCNO heterojunction shows a significantly enhanced photocatalytic activity with the CO production rate of 4.69 μmol g−1 h−1, which is about 12.31 and 1.95 times higher than that of bare ZnIn 2 S 4 and KCa 2 Nb 3 O 10 under simulated sunlight irradiation. The as-prepared ZnIn 2 S 4 /KCNO nanosheet heterojunctions exhibit tremendously improved charge transfer and separation efficiency. The ultrathin structure KCNO is conducive to the rapid transmission of photogenerated electrons, while the nanoflower-like structure ZnIn 2 S 4 is conducive to the full contact with the reactants to produce more protons, resulting in significantly boosted CO production performance. This work gives a new strategy to construct 2D/2D nanosheet heterojunctions for photocatalytic CO 2 conversion, which can offer significant inspirations for other 2D hybrid systems. [ABSTRACT FROM AUTHOR]

With the development of visible-light-driven photocatalytic systems, the Z-scheme system has been paid more attention for water-splitting and contaminants degradation in an effort to the full utilization of superior band potential between two different semiconductors. Here we present systemic investigation of the reduced graphene oxide (RGO)-based composites, including RGO-Cu 2 O, RGO-Bi 2 WO 6 , RGO-Cu 2 O/Bi 2 WO 6 , Cu 2 O/Bi 2 WO 6 heterojunction and physical mixed RGO + Cu 2 O + Bi 2 WO 6 , to give a clear demonstration of the Z-scheme photocatalytic mechanism. The three-component RGO-Cu 2 O/Bi 2 WO 6 composite showed the highest photocatalytic activity on water splitting, which is about 3 times and 4 times that of RGO-Cu 2 O and Cu 2 O respectively. And it also exhibited an excellent photocatalytic performance with a 86% degradation rate for tetracycline that is about 3 (6) times as high as that of pure Cu 2 O (Bi 2 WO 6). These results demonstrate that the construction of RGO-Cu 2 O/Bi 2 WO 6 Z-scheme system is beneficial to water splitting and pollutant degradation for which the superior band potential of Cu 2 O and Bi 2 WO 6 are fully utilized. This work not only reports a new Z-scheme system of RGO-Cu 2 O/Bi 2 WO 6 but also provides a guide to the design of RGO-based photocatalysts. [ABSTRACT FROM AUTHOR]