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The Ag 2 O/Ag 2 CO 3 /multi-walled carbon nanotube (MWNTs) composite photocatalysts were prepared by calcination of the obtained precipitate. The structures and morphology of as-prepared composite photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS). The Ag 2 O/Ag 2 CO 3 /MWNTs composite photocatalysts exhibit higher degradation rate of ciprofloxacin (CIP) than the pure Ag 2 CO 3 , Ag 2 O/Ag 2 CO 3 and Ag 2 CO 3 /MWNTs under visible light irradiation. The amount of loaded Ag 2 CO 3 onto MWNTs and calcined time for Ag 2 CO 3 /MWNTs were systematically investigated, and the optimal amount of loaded Ag 2 CO 3 and calcined time of Ag 2 CO 3 /MWNTs are 150 wt% and 10 min, respectively. The highest photocatalytic degradation rate of CIP could reach 76% under optimal conditions. The active species trapping experiments were also analyzed, the results show that the holes are main contributor for the degradation processes of CIP, furthermore the electrons, O 2 − and OH are also crucially influenced the photocatalytic degradation processes of CIP. The possible photocatalytic processes of CIP with Ag 2 O/Ag 2 CO 3 /MWNTs composite photocatalyst are also proposed. [ABSTRACT FROM AUTHOR]

Ag/Ag 3 PO 4 /active carbon (AC) composite photocatalysts were successfully synthesized using the simple deposition and photoinduced methods. The structures, morphology and photocatalytic properties of as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS). The Ag/Ag 3 PO 4 /AC composite photocatalysts exhibited a conspicuously improved photocatalytic performance for tetracycline (TC) degradation. The optimal conditions of loaded dosage and photoinduced time were investigated, and the results showed that the photoinduced time played an important role in prepared processes, and also that for the loaded dosage of Ag 3 PO 4 . The DRS analysis showed that the composite photocatalysts exhibited strong absorption ability in the visible light range. The radicals trap experiments demonstrated that there were multiple active species during the degrading process of TC. The possible mechanism of improved photocatalytic activity of Ag–Ag 3 PO 4 /AC composite was also proposed. [ABSTRACT FROM AUTHOR]

S-scheme heterojunction of In 2 O 3 /H 1.5 CN/2Au was prepared by hydrothermal, acidizing and calcination methods. The two-dimensional thin layer H 1.5 CN avoided the aggregation of In 2 O 3 and completed the S-scheme charge transfer with In 2 O 3. Moreover, Au not only enhanced the visible light absorption capacity of composites but also provided more active sites for CO 2 reduction. [Display omitted] • S-scheme heterojunction of In 2 O 3 /H 1.5 CN/2Au achieve CO 2 photocatalytic conversion to CO and CH 4. • The enhanced photocatalytic activity results from effective interfacial charge migration and separation and increased active sites. • The LSPR effect of Au improves the utilization of visible light. The construction of S-scheme heterojunction is of great significance for the photocatalytic reduction of CO 2. Here, we prepared two-dimensional (2D) ultra-thin g-C 3 N 4 by acidifying the carbon nitride precursor, and used In 2 O 3 to construct a S-scheme heterojunction with 2D g-C 3 N 4 , and finally In 2 O 3 /H 1.5 CN was modified with Au nanoparticles. The physicochemical properties of the prepared materials were studied by SEM/TEM, XPS, DRS, PL and photochemical test. Meantime, the S-scheme charge transfer mechanism was demonstrated by UPS and ESR. As a result, on the one hand, S-scheme heterojunction accelerated the transfer of electrons on the CB of In 2 O 3 to the VB of g-C 3 N 4 , avoided the recombination of photon-generated carrier. On the other hand, Au, as an effective cocatalyst, promoted photoinduced electron transfer and provided more active sites for CO 2 reduction and the local surface plasmon resonance phenomenon caused by Au NPs enhanced the visible light absorption capacity of the composite material. Moreover, 2D thin layer of g-C 3 N 4 played a carrier effect to disperse In 2 O 3 cube. Therefore, In 2 O 3 /H 1.5 CN/2Au had stable CO 2 reduction products, and the yields of CO/CH 4 reached 141.24/77.05 μmol/g. [ABSTRACT FROM AUTHOR]

The 3D hierarchical structure of CdS/Ni-MOF inhibits the agglomeration of CdS, improve light harvesting, increase active surface area, reaction sites, promote charge transfer and separation, which greatly improves the efficiency of CO 2 conversion. However, when the CdS is overloaded and its hierarchical structure is destroyed, the heterostructure plays a major role in improving the performance. Based on the above results, we propose the preliminary mechanism of 20%-CdS/Ni-MOF photocatalytic reduction of CO 2. Firstly, under UV–Vis illumination, Ni-MOF and CdS are excited to produce electrons (e−) and holes (h+). Then, because of the tight interface contact, the e- excited by Ni-MOF could be transferred to CdS with more positive CB, and CdS as the active site could reduce CO 2 to CO more effectively. At the same time, the h+ in the VB of Ni-MOF and CdS participate in the oxidation reaction to produce O 2 and H 2 O 2 , which achieving the elimination of holes. Such charge separation and transfer of the electron-hole pairs facilitate enhanced photocatalytic activity. [Display omitted] • The 3D hierarchical heterostructure was synthesized by a simple strategy. • 20%-CdS/Ni-MOF showed excellent performance in the vapor–solid reaction system. • The hierarchical structure and heterostructure of CdS/Ni-MOF play a synergistic role. Fabricating the hierarchical heterostructure is efficient way for enhancing CO 2 conversion of semiconductor photocatalysts. Herein, a simple strategy has been employed to prepare several 3D hierarchical CdS/Ni-MOF heterostructure photocatalysts, and the selective photoreduction of CO 2 to CO under simulated sunlight in the gas–solid phase reactor. Among the prepared photocatalysts, 20%-CdS/Ni-MOF shows the best CO yield, which was 16 times and 7 times that of Ni-MOF and CdS, respectively. By controlling the morphology of the catalyst, we found that the significant improvement in photocatalytic activity can be ascribed to the synergistic effect of heterostructure in CdS/Ni-MOF and its unique hierarchical structure, which can improve the efficiency of charge transmission and provides abundant active sites, etc. Finally, the preliminary photocatalytic mechanism was discussed by in situ FTIR and liquid ultraviolet spectrophotometer. [ABSTRACT FROM AUTHOR]

Pt@CeO 2 /3DCN heterojunction are prepared by calcination method and photoreduction technology. The enhanced photoreduction of CO 2 performance can be ascribed to the synergistic effects of the oxygen vacancies in CeO 2 for CO 2 activation and heterojunction for electron separation. Besides, Pt nanoparticles (NPs) on CeO 2 /3DCN can further promote the transfer of electrons, resulting in higher photocatalytic activity. • The Pt@CeO 2 /3DCN photocatalyst was successfully synthesized. • Pt@45CeO 2 /3DCN exhibit best ability of CO 2 photoreduction under UV light. • The synergy of CeO 2 and 3DCN improves the photocatalytic performance. The conversion of CO 2 into high value-added carbon-based compounds through photocatalytic reduction technology is considered as one of the more promising strategies to solve the greenhouse effect. And construction of heterojunction photocatalysts can promote the separation of photoelectron-hole pairs, so as to achieve higher activity of photocatalytic CO 2 reduction. Hence, Pt@CeO 2 /3DCN heterojunction are prepared by calcination method and photoreduction technology. The photocatalytic results revealed that Pt@CeO 2 /3DCN show better photocatalytic activity for reducing CO 2 into CO and CH 4 , compared with 3DCN. Especially, Pt@45CeO 2 /3DCN shows the maximum photocatalytic activity of 4.69 and 3.03 μmol·h−1·g−1 for CO and CH 4 under UV light irradiation, respectively, and the reduction activity did not decrease significantly after five cycles. The enhanced photoreduction of CO 2 performance can be ascribed to the synergistic effects of the oxygen vacancies in CeO 2 for CO 2 activation and heterojunction for electron separation. Besides, Pt nanoparticles (NPs) on CeO 2 /3DCN can further promote the transfer of electrons, resulting in higher photocatalytic activity. [ABSTRACT FROM AUTHOR]

Ni x Co 2 Al-LDHs@CC is generated on the carbon cloth by hydrothermal method. The morphology and electrochemical performance are changed by adjusting the molar ratio of Ni to get the best electrochemical performance of Ni 1 Co 2 Al-LDHs@CC. The Ni 1 Co 2 Al-LDHs@CC has a high specific capacity of 1772.5 mC cm−2 at a current density of 1 mA cm−2 and it maintains outstanding capacitive retention of 93.3% after 12,000 cycles. • The effect of Ni on morphology, specific surface area and electrochemical properties of NiCoAl-LDHs is studied for the first time. • Ni 1 Co 2 Al-LDHs@CC with ultrathin nanosheet (15 nm) is synthesized by hydrothermal method. • Ni 1 Co 2 Al-LDHs@CC achieves the maximum specific capacity of 1772.5 mC cm−2. • An asymmetric supercapacitor (0.102 mWh cm−2) can light an 8 mm LEDs. Layered double hydroxides (LDHs) is a promising electrode material for supercapacitors (SCs) because its large specific surface area and anionic tunability. Herein, an ultrathin ternary Ni x Co 2 Al layer double hydroxides nanosheet (Ni x Co 2 Al-LDHs) grown on carbon cloth (CC) substrate by hydrothermal synthesis method is reported as a high efficiency battery-type electrode in alkaline medium. The influence of Ni on the electrochemical properties and morphology of ternary metal hydroxide is first studied. By adjusting the molar concentration of nickel, we determine that Ni 1 Co 2 Al-LDHs@CC has the best electrochemical performance. The Ni 1 Co 2 Al-LDHs@CC has a high specific capacity of 1772.5 mC cm−2 at a current density of 1 mA cm−2 and it maintains outstanding capacitive retention of 93.3% after 12,000 cycles. In addition, the obtained Ni 1 Co 2 Al-LDHs@CC//AC asymmetric supercapacitors (ASC) achieves a maximum energy density of 0.102 mWh cm−2 at power density of 0.75 mW cm−2 and keep the capacitance retention of 90.98% after 12,000 cycles to successfully light LEDs (8 mm). Detailed electrochemical kinetic analysis showed that the total capacitance of Ni 1 Co 2 Al-LDHs@CC electrode come from its effective capacitive storage mechanism. It is founded that Ni has influence on the morphology and electrochemistry of ternary metal hydroxide, which provided an effective design idea and method for improving the capacitance of ternary metal hydroxide. [ABSTRACT FROM AUTHOR]