Search

In 2 S 3 -NiS co-decorated MoO 3 @MoS 2 (INS/MoO 3 @MoS 2) heterojunctions were prepared in nonthermal plasma via the in-situ sulfurization for enhancing the solar-light photocatalytic conversion of CO 2 into CH 4 and CO at 423 K. In contrast with hexagonal h-MoO 3 nanorods, CH 4 and CO yields were enhanced by h-MoO 3 @MoS 2 and In 2 S 3 /MoO 3 @MoS 2 , while the increased CH 4 yield and decreased CO yield were obtained by INS/MoO 3 @MoS 2 and NiS/MoO 3 @MoS 2. The optimal 3-INS/MoO 3 @MoS 2 with a nominal NiS-In 2 S 3 content of 5.0 wt% and a In/Ni molar ratio of 2:1 exhibited the best photoreduction activity of CO 2 , of which CH 4 and CO yields were 49.11 and 6.19 μmol g−1 h−1, respectively. It's ascribed to the tight interface for enhancing the visible-light absorption capacity and reinforcing the transfer and separation of charge carriers. S-rich sites and O vacancies were favorable for the adsorption and photoreduction of reactants on the bulks surface. The nonthermal plasma induced in-situ sulfurization was thus a promising route to fabricate metal sulfides-based heterojunctions. [Display omitted] • In 2 S 3 -NiS co-decorated MoO 3 @MoS 2 was obtained by nonthermal plasma. • INS/MoO 3 @MoS 2 exhibited the enhanced photoreduction capacity toward CO 2. • The obtained junction interface favored the transfer and separation of charge carriers. • CO 2 was efficiently reduced into CH 4 and CO under solar-light irradiation. [ABSTRACT FROM AUTHOR]

Abstract Sm 2 O 3 coated with N-doped carbon (Sm 2 O 3 @N-C) nanocomposites were synthesized for the visible light driven degradation of tetracycline and RhB. The photo-degradation efficiency of Sm 2 O 3 @N-C was better than that of Sm 2 O 3 , g-C 3 N 4 , and Sm 2 O 3 /g-C 3 N 4 for the RhB removal. The photocatalytic activity of Sm 2 O 3 @N-C increased and then decreased with an increase in N-doping content for the tetracycline removal. N-doped carbon played a crucial role on the enhanced photocatalytic activity and the stability of Sm 2 O 3 @N-C with a carbon shell of 5 nm. It's ascribed to the special interface between Sm 2 O 3 and N-doped carbon, enhancing visible light sorption, facilitating the charge transfer and restraining the recombination of charge carriers. Highlights • Sm 2 O 3 coated with N-doped carbon was synthesized by the hydrothermal route. • Heterojunction interface facilitated the separation of electron-hole pairs. • Sm 2 O 3 @N-C exhibited the advanced photocatalytic activity and stability. [ABSTRACT FROM AUTHOR]

Abstract Ag-decorated core-shell Sm 2 O 3 @TiO 2 (Ag-Sm@TiO 2) nanocomposites were synthesized for the photocatalytic degradation of rhodamine B (RhB) under visible light irradiation. Compared with core-shell Sm 2 O 3 @TiO 2 nanoparticles, the enhanced photocatalytic activity of Ag-Sm@TiO 2 under visible light region was attributed to the surface plasmonic resonance effect of metallic silver and the interface effect between Sm 2 O 3 and TiO 2 in Fenton reaction system. The heterojunction consisted metallic Ag0 nanoparticles, Sm 2 O 3 core, and TiO 2 shell was suitable for the separation of photoexcited electron-hole pairs and the suppression of charge carriers recombination. In addition, the •OH radical was the key active radicals for the photocatalytic degradation of RhB in visible light region. Removal efficiency of RhB over Ag-Sm@TiO 2 increased and then decreased with the increasing Ag amount, of which the 6-Ag-Sm@TiO 2 with metallic Ag0 nanoparticles of 6.0 wt% exhibited the best photocatalytic activity and slightly deactivated after five cycle times. Highlights • Ag-decorated core-shell Sm 2 O 3 @TiO 2 was prepared via photodeposition route. • 6-Ag-Sm@TiO 2 presented the excellent photocatalytic activity and stability. • Heterojunction interface facilitated the separation of electron-hole pairs. [ABSTRACT FROM AUTHOR]

S-defected In 2 S 3 /ZnS nanospheres were synthesized via a microwave-assisted hydrothermal route for facilitating the solar-light induced photodegradation of tetracycline hydrochloride (TCH). The removal efficiency of TCH over In 2 S 3 /ZnS was higher in comparison to pure ZnS and In 2 S 3. The adsorption-photocatalytic capacity of S-defected In 2 S 3 /ZnS was affected by In 2 S 3 content, TCH concentration, inorganic salts, pH, and quenchers. The removal efficiency of optimal 3-In 2 S 3 /ZnS for TCH solution of 50 mg L−1 was 100% within 90 min, and decreased to 93.26% after five cycle times. The main active species were •O 2 - and h+ in solar-light driven photocatalytic system. The enhanced photocatalytic performance of S-defected In 2 S 3 /ZnS was due to the tight interface between In 2 S 3 and ZnS for the efficient transfer and utilization of photo-induced carriers. [Display omitted] • In 2 S 3 /ZnS nanospheres were prepared by a microwave-assisted hydrothermal route. • Tight interface of In 2 S 3 and ZnS favored the transfer and utilization of charge carriers. • S-defected In 2 S 3 /ZnS exhibited the excellent photocatalytic activity and durability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mg-Al LDO with N-defected g-C 3 N 4 extended solar-light absorption capacity. • N-defected g-C 3 N 4 enhanced the photocatalytic activity of Mg-Al LDO. • The junction favored the transfer and separation of charge carriers. To enhance the photocatalytic activity of Mg-Al layered double oxide (LDO) for solar-light excited RhB removal, Mg-Al LDO coupling with N-defected g-C 3 N 4 (Mg-Al@CN) composites were prepared using Mg-Al layered double hydroxide (LDH) and melamine as raw materials. Compared with Mg-Al LDO, Mg-Al@CN exhibited the better adsorption and photocatalytic capacity of RhB due to the combined effect between Mg-Al LDO and g-C 3 N 4. The removal efficiency of RhB over optimal Mg-Al@CN-3 was 91.12% of 60 mg L-1 RhB solution within 120 min, and decreased to 86.11% after five cycles. The enhanced photocatalytic performance of Mg-Al@CN for RhB removal was due to the narrow band-gap structure, extending visible-light capture, and efficient transfer and separation of photo-generated carriers. •O 2 − radical was vital for the Mg-Al@CN assisted photocatalytic reaction. [ABSTRACT FROM AUTHOR]

To develop Bi 2 S 3 -based heterojunction for efficient solar light induced photoreduction of Cr(VI), flower-like Bi 2 S 3 –In 2 S 3 composites consisted of nanorods were prepared via a microwave-assisted hydrothermal route. In contrast with pure Bi 2 S 3 , Bi 2 S 3 –In 2 S 3 composites exhibited the enhanced photoreduction activity while the decreased adsorption capacity for Cr(VI) removal. The best removal efficiency of 70 mg L−1 Cr(VI) solution (99.86%) was achieved by the optimal 3-Bi 2 S 3 –In 2 S 3 with a Bi/In molar ratio of 4:1 within 140 min. It's ascribed to the narrow band gap for strengthened visible-light response, the tight interface between Bi 2 S 3 and In 2 S 3 for rapid transfer and separation of charge carriers, and the enough S vacancies for highly-efficient active sites of adsorption-photoreduction. However, the long-term photo-corrosion resulted in the slightly inferior reusability of 3-Bi 2 S 3 –In 2 S 3 under solar light irradiation after five cycles. [Display omitted] • Flower-like Bi 2 S 3 –In 2 S 3 was prepared by microwave-assisted hydrothermal route. • Bi 2 S 3 –In 2 S 3 composite presents the enhanced removal efficiency of Cr(VI). • Narrow band gap of Bi 2 S 3 –In 2 S 3 promotes the carrier separation and migration. [ABSTRACT FROM AUTHOR]

In recent years, photocatalysis has been confirmed as an emerging route to eliminate the contaminants such as dyes, antibiotics, and heavy metals from wastewater. To explore MoO 3 -based photocatalyst with excellent photocatalytic activity, BiVO 4 -modified hexagonal h-MoO 3 (BiVO 4 /MoO 3) composites were constructed for solar-light induced photodegradation of tetracycline hydrochloride (TCH) via a chemical precipitation approach. Compared with pure h-MoO 3 , BiVO 4 /MoO 3 exhibited the inferior adsorption capacity while efficient photocatalytic activity. The removal efficiency of TCH over BiVO 4 /MoO 3 was affected by BiVO 4 content, pH, and inorganic ions. For optimal 3-BiVO 4 /MoO 3 with a BiVO 4 content of 4.25%, the adsorption-photocatalytic efficiency of 190 mg L−1 TCH was 97.66% within 160 min, and decreased to 91.35% after five cycles under the same conditions. The quenching experiments indicated that h+ and·O 2 - served as the main species in adsorption-photocatalytic system. The tight junction interface between BiVO 4 and MoO 3 could enhance the visible-light response and the transfer and separation of photoinduced electron-hole pairs. Hence, the excellent activity and durability of BiVO 4 /MoO 3 was favorable for the adsorption-photodegradation of organic pollutants. [Display omitted] • BiVO 4 /MoO 3 enhanced the solar-light photodegradation efficiency of TCH. • h+ and ·O 2 - served as the main species in adsorption-photocatalytic system. • BiVO 4 /MoO 3 promoted the separation and migration of charge carriers. [ABSTRACT FROM AUTHOR]

NiS/CuS-CdS (NiS/Cu x Cd 1-x S) composites were prepared via a one-pot hydrothermal route for the simultaneous photocatalytic removal of methyl orange (MO) and methylene blue (MB) in visible light region. The photocatalytic performances of obtained composites were affected by the Cu/Cd molar ratio, NiS content, MO/MB concentration ratio, pH values, and inorganic ions. Among these samples, the optimal 2-NiS/Cu 0.8 Cd 0.2 S with the NiS content of 3.45 wt% and Cu/Cd molar ratio of 4:1 exhibits the best photocatalytic activity for the simultaneous removal of MO and MB. Compared with 2-NiS/Cu 0.8 Cd 0.2 S alone for MO or MB, the obtained samples exhibits the enhanced removal efficiency of MO while the reduced removal efficiency of MB in mixture solution. The enhanced photocatalytic activity is ascribed to the efficient transfer and separation of charge carriers at the ternary interface of NiS-CuS-CdS heterojunction, in which NiS serves as the electron trapper for prolonging lifetime of photoexcited electrons. The O 2 − and OH radicals play the vital roles in the enhanced photocatalytic activity of 2-NiS/Cu 0.8 Cd 0.2 S for the simultaneous removal of MO and MB. [ABSTRACT FROM AUTHOR]

Mg Al layered double oxide (LDO) nanosheets were coated by B,N-codoped carbon (MA#C(B,N)) for the enhanced photocatalytic degradation of tetracycline hydrochloride (TCH) under solar light irradiation. In contrast with bare Mg Al LDO and BN, MA#C(B,N) nanosheets present higher photocatalytic efficiency for TCH removal. The photocatalytic activity of obtained composites are greatly affected by B,N-codoped content, TCH concentrate, pH, and inorganic ions. The optimal MA#C(B,N)-3 exhibited excellent photocatalytic activity and durability in the visible light region, and its removal efficiency was 98.85% for 120 mg L−1 of TCH solution. B,N-codoped carbon with distorted carbon lattice is favorable for the photo-generated electrons trapping and the charge transfer, meanwhile, Mg Al LDO with sufficient basic sites and oxygen vacancies can accelerate the rapid separation of charge carriers at junction interface, enhancing the photocatalytic activity of MA#C(B,N). Unlabelled Image • Mg Al layered double oxide (LDO) nanosheets were coated by B,N-codoped carbon. • A one-pot calcination approach was employed to prepare MA#C(B,N) nanosheets. • MA#C(B,N) nanosheets exhibited excellent adsorption-photocatalysis capacity. • B,N-codoped carbon can efficiently trap the photo-generated electrons. • Basic sites and oxygen vacancies of Mg Al LDO accelerates the separation of charge carriers. [ABSTRACT FROM AUTHOR]

In this work, N-doped carbon-coated ZnS with a sulfur-vacancy defect (ZnS@N-C) was performed for the visible-light-driven photodegradation of tetracycline hydrochloride (TCH). The obtained ZnS@N-C exhibited enhanced photocatalytic activity compared with ZnS for TCH removal. Among these ZnS@N-C composites, ZnS@N-C-3 with N-doped content of 3.01% (100 nm) presented the best visible-light photocatalytic activity and superior long-term photocatalytic stability after five cycle times for TCH removal in the visible light region. This may be ascribed to the interface between the N-doped carbon shell and ZnS with a sulfur-vacancy defect for efficient charge transfer and the restrained recombination of charge carriers. Electron spin resonance (ESR) results indicate that the ·O2‒ radical plays a crucial role in the enhanced photocatalytic activity of ZnS@N-C-3. [ABSTRACT FROM AUTHOR]

CuInS2/Mg(OH)2 (CIS/Mg(OH)2) nanosheets have been prepared for the visible light activated photodegradation of tetracycline hydrochloride (TCH). The introduction of CuInS2 has proven to enhance the photocatalytic activity of Mg(OH)2 nanosheets. It's ascribed to the enhanced transfer and separation of charge carriers at the junction interface between CuInS2 and Mg(OH)2. The photocatalytic activity of obtained CIS/Mg(OH)2 is greatly affected by CuInS2 content, pH value, and inorganic ions. Among these samples, 2-CIS/Mg(OH)2 exhibits the excellent photocatalytic activity and durability for the visible light driven removal of TCH after five cycle times. Atomic force microscope (AFM) images indicate that the surface roughness of 2-CIS/Mg(OH)2 is intensively influenced in adsorption-photocatalysis process. The •O2− and •OH radicals are vital for the visible light driven photocatalytic activity of 2-CIS/Mg(OH)2 for TCH removal. [ABSTRACT FROM AUTHOR]

Developing highly recyclable photocatalysts is crucial for the industrial application of solar-light driven wastewater treatment. Hence, S,N,P-codoped carbon (SNP–C) nanofibers are modified with MoS 2 (MoS 2 /SNP-C) via the electrospinning and nonthermal plasma-sulfurized approaches for enhancing the adsorption and photocatalytic efficiency. The adsorption and photocatalytic capacities of MoS 2 /SNP-C composites for visible-light induced RhB removal are greatly affected by the mass ratio of Mo/P and sulfurized time. Langmuir and second-order models well fit with the adsorption isotherms and kinetics of these composites, respectively. 4-MoS 2 /SNP-C with the nominal Mo/P mass ratio of 12:1 and the sulfurized time of 30 min presents the best adsorption-photocatalytic activity, and its adsorption capacity and removal efficiency of RhB are 728.80 mg g−1 and 99.79%, respectively. The in-situ plasma induced sulfurization is likely to generate the sufficient vacant sites of RhB adsorption and the tight interface between MoS 2 and SNP-C for the rapid transfer of charge carriers. [ABSTRACT FROM AUTHOR]

Solar-light driven water splitting acted as an important technology to solve the energy crisis has attracted much more attention. To restrain the recombination rate of charge carriers and enhance the surface activity of TiO 2 , integrating dual CdS–CoS with S,N-codoped TiO 2 with a Cd/Co mole ratio of 1:1 (Cd 0.5 Co 0.5 S/SN-TiO 2) nano-fibers were fabricated via the electro-spinning and one-pot hydrothermal routes. H 2 -evolution rate of Cd 0.5 Co 0.5 S/SN-TiO 2 nano-fibers was higher than TiO 2 , CoS/SN-TiO 2 and CdS/SN-TiO 2 nano-fibers. The optimal 3-Cd 0.5 Co 0.5 S/SN-TiO 2 with a Cd 0.5 Co 0.5 S ratio of 5.0 wt% performed the highest photocatalytic activity (4.55 mmol g−1 h−1), and the best photocatalytic durability after five cycles. It's owing to the hybrid effect of CdS and CoS for efficient transfer and separation of charge carriers at the junction interface between Cd 0.5 Co 0.5 S nanoparticles and S,N-codoped TiO 2 nanofibers. Meanwhile, the extending visible-light response and sufficient active sites of TiO 2 -based heterojunctions are favorable for the water splitting. [Display omitted] • Cd 0.5 Co 0.5 S/S,N–TiO 2 nanofibers were prepared via electrospinning and hydrothermal routes. • Cd 0.5 Co 0.5 S/S,N–TiO 2 exhibited excellent H 2 -evolution activity. • The tight junction interface favored the transfer and separation of charge carriers. [ABSTRACT FROM AUTHOR]

To extend the application of kaolin in solar-light induced water splitting, MnS-CdS solid solution modified S-doped kaolin (Mn x Cd 1−x S/S-kaolin) composites were in-situ prepared via the high-temperature sulfurization. Compared with kaolin and S-doped kaolin, MnS and CdS greatly enhanced H 2 evolution rate, especially Mn x Cd 1−x S. H 2 evolution rate was affected by Mn/Cd molar ratio, Mn 0.5 Cd 0.5 S content, and sulfurized temperature. The optimal 4-Mn 0.5 Cd 0.5 S/S-kaolin with a Mn/Cd molar ratio of 1:1 and a nominal Mn 0.5 Cd 0.5 S content of 28% treated at 823 K could obtain the highest H 2 evolution rate (4955.27 μmol g−1 h−1), which was 49.33 and 25.28 folds higher than kaolin and S-doped kaolin, respectively. H 2 evolution capacity of 4-Mn 0.5 Cd 0.5 S/S-kaolin decreased from 24,476.79 to 24,262.35 μmol g−1 after five cycles. It's ascribed to the tight interface among S-doped kaolin, MnS and CdS for the efficient transfer and migration of photo-excited charges, and the sufficient active sites formed in S-doped kaolin and S-defected Mn 0.5 Cd 0.5 S were suitable for the efficient photon utilization and visible-light harvesting. [Display omitted] • Mn x Cd 1−x S/kaolin was prepared via high-temperature sulfurization. • H 2 evolution rate of optimal Mn 0.5 Cd 0.5 S/kaolin was 4955.27 μmol g−1 h−1. • The tight junction interface favored the transfer and separation of charge carriers. [ABSTRACT FROM AUTHOR]

To enhance the intrinsic active sites and to suppress the recombination of charge carriers, ZnIn 2 S 4 modified with S,N-codoped carbon (ZIS/SN-C) composites were prepared for solar light driven water splitting via the one-pot sulfurized route. Compared with g-C 3 N 4 and S-doped g-C 3 N 4 , the combined effect between S,N-codoped carbon and ZnIn 2 S 4 can greatly enhance the photocatalytic activity of ZIS/SN-C. The optimal 4-ZIS/SN-C with the Zn(II) content of 13.78% and the calculated In/Zn molar ratio of 2.03:1 presents the H 2 evolution rate of 2937.1 μmol g−1 h−1, which is 2.98 and 23.42 times higher than that of one-pot sulfurized ZnIn 2 S 4 and S-doped g-C 3 N 4 , respectively. However, long-term photo-corrosion induces to the declined durability of 4-ZIS/SN/C for water splitting after three cycles. S vacancies of ZnIn 2 S 4 serve as the efficient active sites of H 2 evolution reaction, and S, N-codoped carbon acts as the photo-induced electrons trapper. The one-pot sulfurized approach is thus a potential strategy to fabricate metal sulfide-based photocatalysts. • ZnIn 2 S 4 /S,N-codoped carbon composites was prepared via one-pot vulcanized route. • ZnIn 2 S 4 /S,N-codoped carbon exhibits the excellent solar light driven H 2 evolution. • S vacancies of ZnIn 2 S 4 serve as the efficient active sites for H 2 evolution reaction. • S, N-codoped carbon acts as the photo-induced electrons trapping. [ABSTRACT FROM AUTHOR]

BiOCl 0.5 X 0.5 (X = F, Br, and I) heterojunctions were prepared via the solvothermal approach to achieve the solar-light induced photodegradation of tetracycline hydrochloride (TCH). The photocatalytic activity of BiOCl coupling with BiOI is greatly affected by the molar ratio of Cl/I. The best photocatalytic efficiency of 97.9 % within 120 min is obtained by flower-like BiOCl 0.5 I 0.5 microspheres with a Cl/I molar ratio of 1:1, and the removal efficiency of TCH over BiOCl 0.5 I 0.5 declines to 93.2 % after five cycles. Compared with BiOCl 0.5 Br 0.5 and BiOCl 0.5 F 0.5 , BiOCl 0.5 I 0.5 presents the better photocatalytic activity. Z-scheme junction between BiOCl and BiOI is favorable for the efficient separation and migration of photo-generated charge carriers, and the narrow band-gap structure of BiOCl 0.5 I 0.5 microspheres favors the visible-light harvesting.·O 2 - plays a vital role in BiOCl 0.5 I 0.5 -assisted photocatalytic reaction. However, the change in valance states induced by photo-corrosion is responsible for the solar-light deactivation of BiOCl 0.5 I 0.5. [Display omitted] • BiOCl 0.5 X 0.5 (X = F, Br, and I) heterojunctions have excellent photodegradation activity. • Z-scheme BiOCl 0.5 I 0.5 junction favors the rapid transfer and separation of charge carriers. • BiOCl 0.5 I 0.5 (2.09 eV) has narrow band-gap structure for visible-light harvesting. [ABSTRACT FROM AUTHOR]

• The rare-earth oxides modified Mg-Al LDO nanosheets were prepared. • La 2 O 3 /Mg-Al composites enhance the adsorption-photocatalytic activity. • Junction structure favors the visible light harvesting and the charge tansfer. Mg-Al layered double oxides (LDO) nanosheets were modified by rare-earth oxides such as La 2 O 3 , Sm 2 O 3 , and Er 2 O 3 (M/Mg-Al, M = La, Sm, and Er) via a one-pot hydrothermal route for the solar-light induced adsorption-photocatalytic degradation of tetracycline hydrochloride (TCH). These rare-earth oxides can greatly enhance the adsorption-photocatalytic activity of Mg-Al based composites, especially La 2 O 3. It's attributed to the efficient adsorption of vacant sites and the rapid transfer and separation of charge carriers at the junction interface. The La 2 O 3 content, pH value, and inorganic ions intensively affect the adsorption-photocatalytic performance of La/Mg-Al. The optimal 2-La/Mg-Al with the La 2 O 3 content of 4.35 % exhibits the best removal efficiency of TCH and the excellent photocatalytic durability. The removal efficiency of TCH (100 mg L−1) is 99.87 % within 110 min, and reduces to 95.88 % after five cycle times. The adsorption isotherms and kinetic behaviors of M/Mg-Al (M = La, Sm, and Er) for TCH removal are well described by Langmuir isotherm and second-order model, respectively. The active radicals such as OH and O 2 − are responsible for the solar light driven photocatalytic degradation of TCH. [ABSTRACT FROM AUTHOR]

Adsorption-photo-reduction is considered as a potential route to remove Cr(VI) from wastewater. To explore the novel photocatalysts with efficient adsorption-photocatalytic activity, flower-like hierarchical ZnS-Ga 2 S 3 heterojunction was prepared for the solar-light-driven reduction of Cr(VI). Its adsorption-photocatalytic capacity is greatly affected by the ZnS/Ga 2 S 3 molar ratio, Cr(VI) content, pH values, and inorganic ions. Among these obtained composites, ZnS-Ga 2 S 3 -3 with a ZnS/Ga 2 S 3 molar ratio of 3:1 exhibits the best adsorption-photocatalytic capacity. The adsorption capacity of ZnS-Ga 2 S 3 -3 is 54.42 mg g−1, and its total removal efficiency is 99.10% for 100 mg L−1 Cr(VI) solution after 160 min. In addition, the adsorption-photo-reduction performance of ZnS-Ga 2 S 3 -3 is slightly deactivated after nine cycle times. The Langmuir, pseudo-second-order, and first-order models well describe the adsorption isotherm, adsorption kinetic, and photo-reduction kinetic of ZnS-Ga 2 S 3 -3, respectively. The synergy effect of ZnS and Ga 2 S 3 are favorable for the efficient transfer and separation of charge carriers, and provide sufficient vacant sites at the junction interface for the adsorption of Cr(VI). Image 1 • Flower-like hierarchical ZnS-Ga 2 S 3 was prepared by the hydrothermal route. • ZnS-Ga 2 S 3 heterojunction has excellent adsorption-photocatalysis capacity. • ZnS-Ga 2 S 3 exhibits slight deactivation for Cr(VI) removal after nine cycle times. [ABSTRACT FROM AUTHOR]

• CeO 2 /Mg-Al nanosheets were prepared by a one-pot hydrothermal route. • CeO 2 /Mg-Al composites exhibit the enhanced photocatalytic activity for Cr(VI) removal. • Surface-defect structure favors the visible light harvesting and separation of charge carriers. CeO 2 -modified Mg-Al layered double oxide (CeO 2 /Mg-Al LDO) nanosheets were prepared via a one-pot hydrothermal route for visible-light induced photocatalytic reduction of Cr(VI). The addition of CeO 2 can enhance the visible light harvesting capacity and the separation of charge carriers of CeO 2 /Mg-Al composites due to the surface-defect structures of Ce(III)/Ce(IV) couple and oxygen vacancies. The photocatalytic activity of CeO 2 /Mg-Al is affected by CeO 2 content, Cr(VI) concentration, co-existing inorganic ions, and initial pH value. Among these obtained composites, CeO 2 /Mg-Al-2 with a nominal Mg/Al molar ratio of 2:1 and CeO 2 content of 6.0 wt% presents the best photocatalytic efficiency and stability. The removal efficiency of Cr(VI) in the CeO 2 /Mg-Al-2-assisted photocatalytic system is varied from 96.76% to 92.87% after five cycle times. The quenching behaviors of active species and the possible photocatalytic mechanism of CeO 2 /Mg-Al-2 were proposed for the conversion of Cr(VI) into Cr(III) in the visible light region. [ABSTRACT FROM AUTHOR]