Waste-to-Energy Conversion on Graphitic Carbon ... - ACS Publications

Letter Cite This: ACS Sustainable Chem. Eng. 2017, 5, 9667-9672

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Waste-to-Energy Conversion on Graphitic Carbon Nitride: Utilizing the Transformation of Macrolide Antibiotics To Enhance Photoinduced Hydrogen Production Zheng Xu, Shasha Xu, Nan Li, Fei Wu, Shichang Chen, Wangyang Lu,* and Wenxing Chen* National Engineering Lab for Textile Fiber Material & Processing Technology (Zhejiang), Zhejiang Sci-Tech University, No. 2 Street, Xiasha, Hangzhou 310018, People’s Republic of China

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S Supporting Information *

ABSTRACT: Photocatalytic H2 evolution is usually from pure water or water with sacrificial agents. Surprisingly, it has been found that the presence of poisonous macrolide antibiotics in an aqueous medium for catalytic H2 evolution enhances the H2 yield while itself being degraded, using Pt/graphitic carbon nitride (Pt/ g-C3N4) under visible light (λ > 420 nm). Hence, a promising method that addresses the issues of energy shortage and environmental pollution is proposed. Among macrolide antibiotics, Roxithromycin (Rox) is so effective in facilitating the decomposition of water that it can be acted as a model in this paper to explain phenomenon as mentioned above. Furthermore, the mechanism of the reaction is also explored and 13 intermediates of Rox are identified by ultraperformance liquid chromatography and high-resolution mass spectrometry. The degradation pathway of Rox is proposed on the basis of the identified intermediates. In the whole process, both energy generation and pollutant control can be achieved simultaneously. Thereby, this represents a surprising waste-to-energy conversion process. KEYWORDS: Macrolide antibiotics, Graphitic carbon nitride, Hydrogen, Photocatalysis, Water splitting

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erate charge separation;27,28 forming nanostructuring to optimize distribution of light and promote charge separation;29−32 and introducing mesopores to accelerate charge separation.33 In order to improve the reaction efficiency, Pt is used as a cocatalyst to enhance the transfer of photoinduced charge. In this work, Pt/g-C3N4 has been synthesized by using a photodeposition method as the loading process. Characterization of the Pt/g-C3N4 by transmission electron microscopy (TEM) and high-resolution TEM showed that Pt had been successfully deposited and uniformly dispersed in the g-C3N4 (Figure S1). It was verified that the photoelectrochemical properties were improved by Pt (Figures S2−S4). Moreover, other properties have no obvious change (Figure S5). The hydrogen yield was clearly significantly enhanced after introducing Pt on the surface of g-C3N4, and 2 wt % Pt/gC3N4 displayed the highest activity (Figure S6). In Figure S7b, we can find Pt4+ has been reduced into Pt2+ and Pt0 completely. Meanwhile, it also explains that Pt0 plays an important role in accelerating the evolution of hydrogen.34 However, not every pollutant present in water contributes to enhancing hydrogen production during the degradation process

INTRODUCTION Sustainable photocatalytic H2 evolution is regarded as a highly effective and promising solution to the energy shortage and environmental pollution.1−3 Since the pioneering work of Fujishima and Honda on photoelectrochemical hydrogen evolution over TiO2,4 such photocatalysis has attracted the interest of many researchers due to its potential application in direct water splitting to afford hydrogen, and for water purification by the degradation of organic contaminants.5−7 However, to the best of our knowledge, most of researchers focus on either how to split water or purify water.8−11 The combination of water purification with the direct utilization of solar energy for hydrogen fuel production by water splitting in a single process has rarely been achieved.12 Among the various polymeric photocatalysts, graphitic carbon nitride (g-C3N4) has attracted tremendous attention, as it is nontoxic, chemically stable, easily modified, and strongly visible-light responsive.13−17 However, pure g-C3N4 shows low efficiency for hydrogen evolution in practical applications owing to a low efficiency of electron−hole separation and a high recombination rate of photogenerated charge carriers.18−20 Therefore, great efforts have been made to accelerate the hydrogen evolution rate of g-C3N4, such as by doping to optimize the capture of light and improve the charge-separation kinetics;21−26 preparing heterojunction/composites to accel© 2017 American Chemical Society

Received: September 3, 2017 Revised: October 3, 2017 Published: October 19, 2017 9667

DOI: 10.1021/acssuschemeng.7b03088 ACS Sustainable Chem. Eng. 2017, 5, 9667−9672

Letter

ACS Sustainable Chemistry & Engineering over Pt/g-C3N4 under visible light. For example, it is not possible to accelerate photocatalytic H2 evolution by using Pt/ g-C3N4 with the simultaneous removal of phenol (Figure S8). With the aim of constructing a system that combines water reduction with contaminant elimination, various contaminants have been explored in our work. Surprisingly, macrolide antibiotics, which are harmful to humans even at low concentrations in drinking water, exerting long-term biological effects,35−37 can act as a sacrificial agent that can enhance the decomposition of water. In this single process, the two purposes mentioned above can be achieved simultaneously. It not only provides a new solution to the energy shortage and environmental pollution but also improves the efficiency of resource utilization.

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RESULTS AND DISCUSSION Among of macrolide antibiotics, Rox is taken as a typical model in this paper. In Figure 1, it can be seen that the hydrogen yield

Figure 2. Photocatalytic water splitting to hydrogen using 40 mg 2 wt %Pt/g-C3N4 and some substrates in the 100 mL water under the visible light irradiation and the oxygen-free environment. Substrates are 0, 5, 10, 15 and 20 mg Rox, respectively.

Figure 1. Photocatalytic water splitting to hydrogen using 40 mg 2 wt %Pt/g-C3N4 and some substrates in the 100 mL water under the visible light irradiation (by a 300 W Xe lamp using a filter allowing λ > 420 nm) and the oxygen-free environment. Substrate is 15 mg Rox. Red column represents the removal rate of the Rox and the black line represents the evolution of hydrogen.

Figure 3. Photocatalytic water splitting to hydrogen using 40 mg 2 wt %Pt/g-C3N4 and some substrates in the 100 mL water under the visible light irradiation and the oxygen-free environment. Substrates are 20 mg Rox, 20 mg Claricid, and 20 mg Kitasamycin, respectively.

increased significantly with the degradation of Rox. In this case, Rox was initially degraded within 4 h, and simultaneously the evolution of hydrogen increased significantly. Thereafter, following the degradation of Rox, the hydrogen yield increased only gradually. Finally, Rox was completely removed within 7 h, and the rate of hydrogen production leveled off. Thus, the rate of hydrogen production was seen to follow the same trend as the degradation rate of Rox, indicating a relationship between these processes. Moreover, further experiments were conducted to show that the hydrogen yield was proportional to the amount of Rox in water (Figure 2). When the amount of Rox was 15 mg or more, the hydrogen yield increased significantly. Although 5 or 10 mg Rox in water led to higher hydrogen production compared to that from pure water, this enhancement effect was no longer seen after 3 h, suggesting that the Rox had been completely removed in this period. Consequently, it was clearly demonstrated Rox has a positive effect on photoinduced hydrogen production. Next, we compared the efficacy of Rox with those of the structurally similar Claricid and Kitasamycin (Figure S9). It was found that both of these compounds also facilitated the decomposition of water (Figure 3). It is of interest to note that

although the hydrogen yields in these experiments were higher than that from pure water, Rox was the most effective, and there was almost no difference in the lower hydrogen yields with Claricid and Kitasamycin. To elucidate the reasons for its increased activity, a comprehensive degradation pathway of Rox was deduced. During the degradation of Rox, the first product was P1 (Figure 4), formed by the loss of −CH2 from an −NMe group. P1 can be further degraded into three intermediates (P2, P3, and P4). Thereafter, nine intermediates can be formed through further reaction of intermediates P2, P3, and P4. Finally, a small amount of citric acid can be detected (Table S1). According to previous studies on oximes,38−40 the products P6 and P10 can be expected to go through the following two processes, taking P10 as an example. In Figure 5a, it can be seen that Pt/g-C3N4, like Au-TiO2, may catalyze the chemoselective hydrogenation of oxime P10 with H2, thereby avoiding the generation of hydroxylamine, which is a noxious and unstable product. Therefore, it can be assumed that product P12 will be generated in the reaction. Simultaneously, it is also evident 9668


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ACS Sustainable Chemistry & Engineering

Figure 4. Pathway of Rox degradation.

evolution of hydrogen. It is for this reason that the efficiency of hydrogen production in the presence of Rox in water is higher than with Claricid or Kitasamycin. Consequently, water is needed as an oxidizing agent in Rox degradation according to the following stoichiometry (Figure 4):

from Figure 3 that the partial consumption of H2 will result in an apparently lower rate of H2 evolution in 2 h under irradiation. Additionally, a new system can be envisaged when Rox is converted into oxime P10 (Figure 5b). The H+ exchange site will be closer to the Pt center, allowing intermolecular proton transfer in a cyclic intermediate, thereby enhancing the 9669


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Figure 5. (a) Pathway of the degradation about P10 to P12; (b) mechanisms of P10 enhancing the evolution of hydrogen under the visible light irradiation (by a 300 W Xe lamp using a filter allowing λ > 420 nm) and the oxygen-free environment.

C41H 76N2O15 + 43H 2O → 6C6H8O7 + 5CO2 + 57H 2 + 2NO3−

(1)

In contrast to Figure 1, there was a slight difference between the theoretical hydrogen yield and that obtained in practice. Further observation revealed that a lot of intermediates remained in solution after irradiation for 7 h. The findings were also consistent with the mineralization of Rox being incomplete after 7 h, although it was thoroughly decomposed (Figure S10). Hence, a possible equation for the complete mineralization of Rox is proposed: C41H 76N2O15 + 73H 2O → 41CO2 + 111H 2 + 2NO3− (2)

According to Equation 2, for every 1 mol of Rox degraded, 111 mol of hydrogen will be produced. Thus, if Rox can be completely mineralized, the hydrogen yield will be enormous. Therefore, it is further illustrated that the intermediates, mainly P6 and P10, can enhance the evolution of hydrogen. Considering practical application, the stability and cyclability of the process are also important. From Figure 6, it can be seen that the hydrogen yield increased steadily with each cycle, and the process was relatively stable. It is worth noting that the evolution of hydrogen increased a little after the first cycle. The reason for this phenomenon is that residual unpaired P6 or P10 from the previous cycle and the newly formed P6 or P10 combine with Pt to construct a system as mentioned above. Therefore, it is also proved that these intermediates can enhance water decomposition. On the basis of the above findings, a probable mechanism for photoinduced reduction of water and degradation of Rox in a single process using Pt/g-C3N4 can be proposed (Figure 7). The g-C3N4 produces hydrogen from water according to the process:

Figure 6. Photocatalytic water splitting to hydrogen using 40 mg 2 wt %Pt/g-C3N4 and 5 mg Rox in the 100 mL water under the visible light irradiation (by a 300 W Xe lamp using a filter allowing λ > 420 nm) and the oxygen-free environment. Stabilities of hydrogen evolution over the mention above system, the reaction was continued for 15 h. After every run, 5 mg Rox added into the system.

2H 2O → H 2O2 + H 2

(3)

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Because of the low quantum efficiency of g-C3N4, Pt is introduced on its surface to improve its photocatalytic reactivity, preventing electron−hole recombination. It is worthy of note that H2O2 is a negative factor for the decomposition of water because it can be adsorbed on the surface of g-C3N4, where it exerts a poisoning effect. Therefore, to facilitate hydrogen production, Rox as an electron donor and/or an oxygen scavenger serves to consume H2O2.42 Simultaneously, a lot of intermediates will be degraded by photogenerated holes. Among the various intermediates, oximes P6 and P10 play 9670


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Figure 7. Proposed reaction mechanism for enhancing splitting water to hydrogen and degrading the Rox simultaneously by using Pt/g-C3N4 under the visible light.

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important roles in enhancing water splitting to hydrogen. Most prominently, a new system is formed by P6 or P10 combining with Pt, which can facilitate intermolecular proton transfer. Ultimately, Rox acts as a sacrificial agent to facilitate photoinduced hydrogen production, while itself being degraded.

*E-mail: [email protected] (W. Lu), Tel./Fax: +86-571-86843611. *E-mail: [email protected] (W. Chen), Tel./Fax: +86-5718684-3611.

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ORCID

CONCLUSION In conclusion, our work provides a solution for the photodecomposition of water and the degradation of macrolide antibiotics (e.g., Rox) in a single process by using Pt/g-C3N4. It is found that macrolide antibiotics present in water act as a sacrificial agent to consume H2O2, itself being degraded, leading to an enhancement of the hydrogen yield. Indeed, the hydrogen yield is proportional to the amount of macrolide antibiotics present in the water. The enhanced rate of photoinduced hydrogen production and efficient macrolide antibiotics degradation are the most remarkable highlights of the whole process. Excitingly, this work offers a new strategy for addressing the energy shortage and environmental pollution in a single process. Therefore, this photocatalytic technology can be regarded as a promising solution to be applied in wastewater purification with the aim of deriving hydrogen from the organic contaminants present therein.

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AUTHOR INFORMATION

Corresponding Authors

Wenxing Chen: 0000-0002-4554-1455 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No. 51133006), the Public Technology Application Research Project of Zhejiang Province (No. 2015C33018).

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REFERENCES

(1) Lakadamyali, F.; Reisner, E. Photocatalytic H2 evolution from neutral water with a molecular cobalt catalyst on a dye-sensitised TiO2 nanoparticle. Chem. Commun. 2011, 47 (6), 1695. (2) Zhang, R.; Fang, Y.; Chen, T.; Qu, F.; Liu, Z.; Du, G.; Asiri, A. M.; Gao, T.; Sun, X. Enhanced Photoelectrochemical Water Oxidation Performance of Fe2O3 Nanorods Array by S Doping. ACS Sustainable Chem. Eng. 2017, 5 (9), 7502. (3) Huang, X.; Yang, L.; Hao, S.; Zheng, B.; Yan, L.; Qu, F.; Asiri, A. M.; Sun, X. N-Doped carbon dots: a metal-free co-catalyst on hematite nanorod arrays toward efficient photoelectrochemical water oxidation. Inorg. Chem. Front. 2017, 4 (3), 537. (4) Osterloh, F. E. Inorganic materials as catalysts for photochemical splitting of water. Chem. Mater. 2008, 20 (1), 35−54. (5) Eswar, N. K.; Ramamurthy, P. C.; Madras, G. Novel synergistic photocatalytic degradation of antibiotics and bacteria using V−N doped TiO2 under visible light: the state of nitrogen in V-doped TiO2. New J. Chem. 2016, 40 (4), 3464. (6) Xu, T.; Wu, F.; Gu, Y.; Chen, Y.; Cai, J.; Lu, W.; Hu, H.; Zhu, Z.; Chen, W. Visible-light responsive electrospun nanofibers based on polyacrylonitrile-dispersed graphitic carbon nitride. RSC Adv. 2015, 5 (105), 86505.

ASSOCIATED CONTENT

* Supporting Information S

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acssuschemeng.7b03088. Experimental details of this study, preparation of g-C3N4 and Pt/g-C3N4, characterizations of catalysts (TEM, UV/ vis DRS spectra, photoluminescence spectra, transient photocurrent density responses, thermogravimetric analysis and High resolution of XPS analysis), gas chromatography of CO2 and high-resolution parent and fragment ion data (PDF) 9671


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ACS Sustainable Chemistry & Engineering (7) Jiang, L.; Yuan, X.; Zeng, G.; Chen, X.; Wu, Z.; Liang, J.; Zhang, J.; Wang, H.; Wang, H. Phosphorus- and Sulfur-Codoped g-C3N4: Facile Preparation, Mechanism Insight, and Application as Efficient Photocatalyst for Tetracycline and Methyl Orange Degradation under Visible Light Irradiation. ACS Sustainable Chem. Eng. 2017, 5 (7), 5831. (8) Pan, Y.-X.; Peng, J.-B.; Xin, S.; You, Y.; Men, Y.-L.; Zhang, F.; Duan, M.-Y.; Cui, Y.; Sun, Z.-Q.; Song, J. Enhanced Visible-LightDriven Photocatalytic H-2 Evolution from Water on Noble-Metal-Free CdS-Nanoparticle-Dispersed Mo2C@C Nanospheres. ACS Sustainable Chem. Eng. 2017, 5 (6), 5449. (9) Jeong, S.; Chung, K.-H.; Lee, H.; Park, H.; Jeon, K.-J.; Park, Y.-K.; Jung, S.-C. Enhancement of Hydrogen Evolution from Water Photocatalysis Using Liquid Phase Plasma on Metal Oxide-Loaded Photocatalysts. ACS Sustainable Chem. Eng. 2017, 5 (5), 3659. (10) Gu, Q.; Sun, H.; Xie, Z.; Gao, Z.; Xue, C. MoS2-coated microspheres of self-sensitized carbon nitride for efficient photocatalytic hydrogen generation under visible light irradiation. Appl. Surf. Sci. 2017, 396, 1808. (11) Osterloh, F. E. Inorganic nanostructures for photoelectrochemical and photocatalytic water splitting. Chem. Soc. Rev. 2013, 42 (6), 2294. (12) Patsoura, A.; Kondarides, D. I.; Verykios, X. E. Enhancement of photoinduced hydrogen production from irradiated Pt/TiO2 suspensions with simultaneous degradation of azo-dyes. Appl. Catal., B 2006, 64 (3−4), 171. (13) Wang, X.; Maeda, K.; Thomas, A.; Takanabe, K.; Xin, G.; Carlsson, J. M.; Domen, K.; Antonietti, M. A metal-free polymeric photocatalyst for hydrogen production from water under visible light. Nat. Mater. 2009, 8 (1), 76. (14) Chen, F.; Yang, H.; Wang, X.; Yu, H. Facile synthesis and enhanced photocatalytic H2 -evolution performance of NiS2 -modified g-C3N4 photocatalysts. Chinese Journal of Catalysis 2017, 38 (2), 296. (15) Yu, W.; Chen, J.; Shang, T.; Chen, L.; Gu, L.; Peng, T. Direct Zscheme g-C3N4/WO3 photocatalyst with atomically defined junction for H2 production. Appl. Catal., B 2017, 219, 693. (16) Tu, W.; Xu, Y.; Wang, J.; Zhang, B.; Zhou, T.; Yin, S.; Wu, S.; Li, C.; Huang, Y.; Zhou, Y.; Zou, Z.; Robertson, J.; Kraft, M.; Xu, R. Investigating the Role of Tunable Nitrogen Vacancies in Graphitic Carbon Nitride Nanosheets for Efficient Visible-Light-Driven H2 Evolution and CO2 Reduction. ACS Sustainable Chem. Eng. 2017, 5 (8), 7260. (17) Gholipour, M. R.; Béland, F.; Do, T.-O. Post-Calcined Carbon Nitride Nanosheets as an Efficient Photocatalyst for Hydrogen Production under Visible Light Irradiation. ACS Sustainable Chem. Eng. 2017, 5 (1), 213. (18) Patnaik, S.; Martha, S.; Madras, G.; Parida, K. The effect of sulfate pre-treatment to improve the deposition of Au-nanoparticles in a gold-modified sulfated g-C3N4 plasmonic photocatalyst towards visible light induced water reduction reaction. Phys. Chem. Chem. Phys. 2016, 18 (41), 28502. (19) He, K.; Xie, J.; Luo, X.; Wen, J.; Ma, S.; Li, X.; Fang, Y.; Zhang, X. Enhanced visible light photocatalytic H2 production over Z-scheme g-C3N4 nansheets/WO3 nanorods nanocomposites loaded with Ni(OH)x cocatalysts. Chinese Journal of Catalysis 2017, 38 (2), 240. (20) Patnaik, S.; Martha, S.; Parida, K. M. An overview of the structural, textural and morphological modulations of g-C3N4 towards photocatalytic hydrogen production. RSC Adv. 2016, 6 (52), 46929. (21) Samanta, S.; Martha, S.; Parida, K. Facile Synthesis of Au/gC3N4 Nanocomposites: An Inorganic/Organic Hybrid Plasmonic Photocatalyst with Enhanced Hydrogen Gas Evolution Under VisibleLight Irradiation. ChemCatChem 2014, n/a. (22) Li, Z.; Kong, C.; Lu, G. Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and FeDoped g-C3N4. J. Phys. Chem. C 2016, 120 (1), 56. (23) Lin, Z.; Wang, X. Nanostructure Engineering and Doping of Conjugated Carbon Nitride Semiconductors for Hydrogen Photosynthesis. Angew. Chem., Int. Ed. 2013, 52 (6), 1735.

(24) Zhang, R.; Yang, L.; Huang, X.; Chen, T.; Qu, F.; Liu, Z.; Du, G.; Asiri, A. M.; Sun, X. Se doping: an effective strategy toward Fe2O3 nanorod arrays for greatly enhanced solar water oxidation. J. Mater. Chem. A 2017, 5 (24), 12086. (25) Zhang, J.; Zhang, G.; Chen, X.; Lin, S.; Moehlmann, L.; Dolega, G.; Lipner, G.; Antonietti, M.; Blechert, S.; Wang, X. Co-Monomer Control of Carbon Nitride Semiconductors to Optimize Hydrogen Evolution with Visible Light. Angew. Chem., Int. Ed. 2012, 51 (13), 3183. (26) Ge, L.; Han, C.; Liu, J.; Li, Y. Enhanced visible light photocatalytic activity of novel polymeric g-C3N4 loaded with Ag nanoparticles. Appl. Catal., A 2011, 409-410, 215. (27) Zhang, J.; Zhang, M.; Sun, R.-Q.; Wang, X. A Facile Band Alignment of Polymeric Carbon Nitride Semiconductors to Construct Isotype Heterojunctions. Angew. Chem., Int. Ed. 2012, 51 (40), 10145. (28) Akple, M. S.; Low, J.; Wageh, S.; Al-Ghamdi, A. A.; Yu, J.; Zhang, J. Enhanced visible light photocatalytic H2-production of gC3N4/WS2 composite heterostructures. Appl. Surf. Sci. 2015, 358, 196. (29) Sun, J.; Zhang, J.; Zhang, M.; Antonietti, M.; Fu, X.; Wang, X. Bioinspired hollow semiconductor nanospheres as photosynthetic nanoparticles. Nat. Commun. 2012, 3, 1139. (30) Zhang, J.; Zhang, M.; Yang, C.; Wang, X. Nanospherical Carbon Nitride Frameworks with Sharp Edges Accelerating Charge Collection and Separation at a Soft Photocatalytic Interface. Adv. Mater. 2014, 26 (24), 4121. (31) Zhang, P.; Wang, T.; Zeng, H. Design of Cu-Cu2O/g-C3N4 nanocomponent photocatalysts for hydrogen evolution under visible light irradiation using water-soluble Erythrosin B dye sensitization. Appl. Surf. Sci. 2017, 391, 404. (32) Zhang, Z.; Zhang, Y.; Lu, L.; Si, Y.; Zhang, S.; Chen, Y.; Dai, K.; Duan, P.; Duan, L.; Liu, J. Graphitic carbon nitride nanosheet for photocatalytic hydrogen production: The impact of morphology and element composition. Appl. Surf. Sci. 2017, 391, 369. (33) He, F.; Chen, G.; Zhou, Y.; Yu, Y.; Zheng, Y.; Hao, S. The facile synthesis of mesoporous g-C3N4 with highly enhanced photocatalytic H2 evolution performance. Chem. Commun. 2015, 51 (90), 16244. (34) Zhang, G.; Lan, Z.-A.; Lin, L.; Lin, S.; Wang, X. Overall water splitting by Pt/g-C3N4photocatalysts without using sacrificial agents. Chem. Sci. 2016, 7 (5), 3062. (35) Schlusener, M. P.; Bester, K.; Spiteller, M. Determination of antibiotics such as macrolides, ionophores and tiamulin in liquid manure by HPLC-MS/MS. Anal. Bioanal. Chem. 2003, 375 (7), 942. (36) Radjenovic, J.; Godehardt, M.; Petrovic, M.; Hein, A.; Farre, M.; Jekel, M.; Barcelo, D. Evidencing Generation of Persistent Ozonation Products of Antibiotics Roxithromycin and Trimethoprim. Environ. Sci. Technol. 2009, 43 (17), 6808. (37) Kwiecień, A.; Krzek, J.; Ż mudzki, P.; Matoga, U.; Długosz, M.; Szczubiałka, K.; Nowakowska, M. Roxithromycin degradation by acidic hydrolysis and photocatalysis. Anal. Methods 2014, 6 (16), 6414. (38) Corma, A.; Serna, P. Chemoselective hydrogenation of nitro compounds with supported gold catalysts. Science 2006, 313 (5785), 332. (39) Klitgaard, S. K.; Egeblad, K.; Mentzel, U. V.; Popov, A. G.; Jensen, T.; Taarning, E.; Nielsen, I. S.; Christensen, C. H. Oxidations of amines with molecular oxygen using bifunctional gold−titania catalysts. Green Chem. 2008, 10 (4), 419. (40) Jacques, P. A.; Artero, V.; Pecaut, J.; Fontecave, M. Cobalt and nickel diimine-dioxime complexes as molecular electrocatalysts for hydrogen evolution with low overvoltages. Proc. Natl. Acad. Sci. U. S. A. 2009, 106 (49), 20627. (41) Liu, J.; Liu, Y.; Liu, N. Y.; Han, Y. Z.; Zhang, X.; Huang, H.; Lifshitz, Y.; Lee, S. T.; Zhong, J.; Kang, Z. H. Metal-free efficient photocatalyst for stable visible water splitting via a two-electron pathway. Science 2015, 347 (6225), 970. (42) Wahba, M. E. Liquid chromatographic determination of roxithromycin: application to stability studies. J. Chromatogr. Sci. 2013, 51 (1), 44.

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