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A Universal Strategy to Prepare Functional Porous Graphene Hybrid Architectures Zhiqiang Niu, Lili Liu, Li Zhang, Qi Shao, Weiya Zhou, Xiaodong Chen,* and Sishen Xie The unique two-dimensional (2D) structure and physical properties of graphene and its derivatives make them distinctive nanoscale building blocks for constructing various novel threedimensional (3D) porous architectures.[1–14] These 3D architectures exhibit high specific surface area as well as fast mass and electron transport kinetics due to the combination of porous structures and the excellent intrinsic properties of graphene and its derivatives.[15–21] Furthermore, incorporating functional nanomaterials into these porous graphene structures to form 3D porous graphene hybrid architectures (GHAs) would enhance their specific applications in energy storage and conversion, environmental remediation, and photocatalysis, because of diverse functionalities and synergistic effect in the composites.[22–37] Several methods, such as template assisted growth,[27–29] chemical vapor deposition (CVD),[30] and chemical self-assembly,[31–36] have been developed to fabricate such 3D porous GHAs. Among these methods, chemical self-assembly is a strikingly elegant and economic approach to organize discrete graphene and functional nanomaterials into 3D hybrid networks with desired sizes and shapes at a large scale.[38] However, there are three remaining challenges which restrict the further development of fabricating 3D porous GHAs by the chemical self-assembly. The first one lies in the difficulty in achieving controllable morphology, mass, and distribution of additive nanomaterials in GHAs, because these additive nanomaterials were usually synthesized by in situ growth,[39,40] which often lacks good control over the reaction process. The second one is the lack of diversity for nanomaterials selection since most of the nanomaterials fabricated by solution-based method or CVD are immiscible and unsuitable to co-assemble with graphene directly to form GHAs.[26] The last one is the need of multi-step process to incorporate multinanomaterials into the 3D porous graphene materials since the growth conditions of diverse nanomaterials are different.[41,42] Considering these challenges, it is desired to find a general method to homogeneously incorporate the functional nanomaterials into graphene structures to form 3D porous GHAs.

Dr. Z. Niu,[+] Dr. L. Liu,[+] Dr. L. Zhang Q. Shao Prof. X. Chen School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue, Singapore 639798, E-mail: [email protected] Prof. W. Zhou, Prof. S. Xie Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190, PR China [+] Z. Niu and L. Liu contributed equally to this work

DOI: 10.1002/adma.201400143

Adv. Mater. 2014, DOI: 10.1002/adma.201400143

As a derivative of graphene, graphene oxide (GO) sheet is hydrophilic due to the existence of functional groups on its defect sites and edges,[26] while its basal plane is essentially hydrophobic due to a network of polyaromatic islands of unoxidized benzene rings.[43] Therefore, GO sheet can be considered as surfactant with a largely hydrophobic basal plane and hydrophilic edge,[44,45] and as a result, it would have the capability to disperse other nanomaterials in water homogeneously. In addition, GO and reduced GO (rGO) are good gelators for polymer, biomolecules, and so on.[6,35] Thus, it is expected that different nanomaterials might be incorporated into a hydrogel by gelating the mixed suspension of GO and other nanomaterials. Here, we report a universal strategy to incorporate various functional nanomaterials into 3D porous GHAs by a one-step hydrothermal co-assembly. This method possesses an environment-friendly process and can be readily scaled up. Furthermore, it can directly co-assemble different nanomaterials into one GHA with a controllable mass ratio. As a proof of concept, the applications of 3D porous GHAs as electrodes for energy storage and optoelectronic devices are presented. The specific performance of these GHAs is remarkably enhanced due to the synergistic properties from rGO and additive nanomaterials. Figure 1a schematically shows the universal experimental procedure. In a typical experiment, nanostructured materials were first added into the GO aqueous suspensions. Then, stable mixed suspensions were obtained by ultrasonication. After that, the vials with suspensions were put into a Teflon (polytetrafluoroethylene) vessel, which was then sealed in a stainless steel autoclave and heated to 180 °C for 3 h. Finally, 3D porous GHAs were obtained by freeze-drying. To verify the feasibility and versatility of our protocol, seven typical nanomaterials, which vary in their solubility in water, sizes, shapes, constituent components, and preparation methods, were used to co-assemble with GO sheets to form GHAs (Supporting Information, Figure S1, Table S1). For example, three one dimensional (1D) nanomaterials (carbon nanotubes (CNTs), InN nanowires (InNNWs), and Zn2SnO4-NWs) were prepared by CVD, whereas the other nanoparticles (NPs) and 1D nanomaterials (Au-NPs, TiO2NPs, polyaniline nanofibers (PANI-NFs) and MnO2-NWs) were fabricated by solution-based approaches. The size of NPs is in the range of 10–25 nm, while for the 1D nanomaterials, their diameter ranges from 10 to 500 nm and the length varies from a few micrometers to more than tens of micrometers. It is noted that the aqueous suspensions of these nanomaterials except Au-NPs are unstable and tend to settle to the bottom slowly, even after ultrasonication, showing medium or poor solubility in water (Figure 1b). However, all these nanomaterials can be well dispersed in GO suspensions by ultrasonication, forming stable mixed suspensions (Figure 1c). As mentioned above, the hydrophobic basal plane and hydrophilic

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Figure 1. a) Schematic of preparing porous GHAs by a hydrothermal co-assembly process. The optical images of Au-NPs, TiO2-NPs, CNTs, PANI-NFs, MnO2-NWs, InN-NWs and Zn2SnO4-NWs in b) water and c) GO aqueous suspension. d) Optical and e) SEM images of rGO/TiO2-NP hybrid architecture. f) Optical image of mixed rGO/TiO2-NP/InN-NW suspension. g) Optical and h) SEM images of rGO/TiO2-NP/InN-NW hybrid architecture.

edges of GO sheet makes it act as a surfactant.[44,46] Furthermore, unlike small molecular surfactants, GO sheet has large lateral dimension and an array of hydrophobic, π-conjugated nanopatches in their basal plane. As a result, in the mixed suspensions, GO sheets are able to capture the nanomaterials with multiple adhesion sites by various interactions between GO sheets and nanomaterials, such as van der Waals interaction, physisorption, hydrophobic or π–π interaction.[43,47] In this case, the GO sheets are much like “buoy”, hence support and prevent insoluble nanomaterials from precipitation, forming stable suspensions. Based on these suspensions, a hydrothermal process was applied to co-assemble additive nanomaterials and GO into rGO composite hydrogels. This resulted in a clean and transparent solution, containing only the integrated hydrogel and no separated rGO sheets or additive nanomaterials (Figure S2 and S3, Supporting Information), indicating an efficient embedding of the additive nanomaterials in the hydrogel. Furthermore, in the hydrothermal process, the GO sheets that are typically insulating were reduced into conductive rGO sheets,[6,48] as indicated by ID/IG intensity ratio of Raman spectra (Figure S4b, Supporting Information).[2] Subsequently, by freeze-drying, porous GHAs were obtained, as shown in Figure 1d and Figure S5b-e. rGO sheets in GHAs still exhibit a well-defined and interconnected 3D network microstructure and the additive nanostructured materials are attached on the surface of rGO and distributed in the GHAs (Figure 1e and Figure S4, Supporting Information). Furthermore, several distinct nanomaterials could be well dispersed in a GO suspension simultaneously to form stable mixed suspension (Figure 1f and the inset of Figure S5f,

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Supporting Information). Based on the mixed suspensions with multi-additives, GHAs containing two additives (rGO/ TiO2-NP/InN-NW) or three additives (rGO/Au-NP/TiO2-NP/ PANI-NF) were fabricated by our one-step hydrothermal co-assembly strategy, as shown in Figure 1g and the inset of Figure S5f, Supporting Information. Both resultant GHAs possess porous structure and the different nanomaterials were uniformly embedded in the graphene networks (Figure 1h and Figure S5f, Supporting Information), indicating the feasibility and universality of our method to co-assemble several different nanomaterials into one architecture simultaneously. We should take note that the diverse shapes of additive nanomaterials have different effects on the microstructures around them in GHAs. As an example, we compared the microstructures of GHAs based on Au-NPs (Figure 2a) and Zn2SnO4-NWs (Figure 2d). In rGO/Au-NP hybrid architectures, the rGO sheets show a continuously cross-linked 3D network with pore size of submicrometer to about two micrometers, and Au-NPs are only embedded in the rGO sheet walls of network. The microstructure of rGO sheets around the Au-NPs is similar to that at the regions where no Au-NPs exist (Figure 2b). Contrastively, in rGO/Zn2SnO4-NW hybrid architectures (Figure 2d), while continuously cross-linked rGO network still formed, its pore size is increased in a range of submicrometer to several micrometers, and the rGO sheets enwrap NWs tightly and shrink severely to NWs. Furthermore, the rGO sheets surrounding Zn2SnO4-NW shrink much more severely than the rGO sheets distant from the NWs, indicating that the NWs enhance the shrinkage of rGO sheets near them, contrary to the case of Au-NPs. The distinct microstructures would be ascribed

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to their different formation mechanism. In the case of Au-NPs, during the hydrothermal process, Au-NPs were driven to attach on rGO sheets due to the van der Waals interaction (Figure S6, Supporting Information),[49–53] and the rGO sheets with Au-NPs were partially overlapped at many sites and crumpled to minimize their surface energies (named as adsorbing-crosslinkingshrinking (ACS)),[6,47,54,55] forming the network structure, as depicted in Figure 2c. However, in the case of Zn2SnO4-NWs, since the size of rGO sheets is smaller than that of Zn2SnO4NWs, rGO sheets tend to wrap and shrink to NWs by multiple adhesion sites due to the enhanced hydrophobic and van der Waals interactions in the hydrothermal process.[43,47] At the same time, the rGO sheets that enwrapped the NWs are also partially overlapped and shrink into a 3D network and NWs lean against each other during the shrinking process of rGO sheets, leading to the increased pore size, as depicted in Figure 2f. Different from the ACS mechanism of rGO/Au-NP hybrid architectures, the formation of rGO/Zn2SnO4-NW hybrid architectures is a wrapping-crosslinking-shrinking (WCS) process (Figure 2f).

Adv. Mater. 2014, DOI: 10.1002/adma.201400143

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Figure 2. a,b) SEM images of rGO/Au-NP hybrid architecture. c) Formation mechanism of GHAs based on small size NPs: adsorbingcrosslinking-shrinking (ACS). SEM images of rGO/Zn2SnO4-NW hybrid architectures with d) high and e) low mass ratio of Zn2SnO4-NW and rGO. f) Formation mechanism of GHAs based on NWs: wrappingcrosslinking-shrinking (WCS).

Compared to other methods to prepare graphene composite materials, such as Langmuir-Blodgett method and layer by layer assembly, the one-step hydrothermal co-assembly strategy has several advantages.[27–30,56,57] First, this method is environment-friendly and scalable. During the hydrothermal co-assembly process, GO sheets are reduced to rGO sheets, and no noxious reduction agents, such as hydrazine, are used. The volume of the resultant GHAs depends on the container of mixed suspensions of GO and additive nanomaterials. Consequently, the volume of the resultant GHAs can be scaled up. Second, it can directly co-assemble different nanomaterials with GO sheets into one GHA by one step. Contrastively, in previously reported,[41,42] different nanomaterials were usually incorporated into one GHA through a multi-step strategy with complicated process since the growth conditions of the additive nanomaterials are different. Third, the mass of additive nanomaterials in the GHAs can be well-controlled. Controllable mass ratio would optimize the performance of GHAs through the synergistic effect from rGO and other functional nanomaterials.[58] Finally, GHAs prepared by our method possess large size pores with diameters in the range of submicrometer to several micrometers. This porous structure would improve the mass and electron transport kinetics through the GHAs and provide large accessible specific surface area.[21] Therefore, the porous graphene hybrid materials prepared by the hydrothermal co-assembly would exhibit excellent performance in energy storage and conversion, due to the combination of porous structures and the synergistic effects between graphene and additive nanomaterials. Here, as a proof of concept, the GHAs based on TiO2-NPs and PANI-NFs were used as electrodes of photoelectrochemical and supercapacitor devices, respectively. TiO2 has been widely studied in the fields of energy conversion owing to its effectiveness, low cost, and chemical stability.[29,59–64] Carbon-based materials with conjugated π systems can often induce synergistic or cooperative effects between the metal oxide and carbon phases.[65] Therefore, we tested the photoelectrochemical behaviors of rGO/TiO2-NP hybrid architectures in a three-electrode configuration, as depicted in Figure 3a. The rGO/TiO2-NP hybrid architectures show a fast and uniform anodic photocurrent responding to each switchon and switch-off event, as shown in Figure 3c. It is different from that of pure rGO architecture, which display a cathodic photocurrent (Figure 3c), corresponding to p-type photoresponse.[60,66] When the mass ratio of TiO2-NPs to rGO sheets (Rm(TiO2 : rGO)) in rGO/TiO2-NP hybrid architectures is 5, a photocurrent of 132 µA cm−2 was obtained (Figure 3d), which is larger than that of pure rGO architecture (31 µA cm−2) and previous reported rGO/TiO2-NP structures.[59–63,67] The reason of this improvement is attributed to the large controllable TiO2NP loading, good connection between rGO sheets and TiO2NPs, and continuous rGO conductive network. The photocurrent response of rGO/TiO2-NP hybrid architectures is mainly determined by the synergistic effect of TiO2-NPs and rGO.[60– 62,68] Upon irradiation with UV light, TiO2-NPs undergo charge separation to yield electrons and holes, and rGO mainly plays a role in conducting the electrons due to its remarkable electrical transport property.[62,68,69] In our rGO/TiO2-NP hybrid architectures, Rm(TiO2 : rGO) can be up to 10 or even more. Large

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Figure 3. a) Sketch of testing photocurrent response of rGO/TiO2-NP hybrid architectures. b) The schematic diagram of charge behavior at the surface of TiO2-NP and rGO sheet under light irradiation. c) Photocurrent responses of pure rGO architecture and rGO/TiO2-NP hybrid architecture (Rm(TiO2 : rGO) = 5) under UV light irradiation in 0.5 M Na2SO4 aqueous solution. d) The photocurrent comparison of rGO/TiO2-NP hybrid architectures with different Rm(TiO2 : rGO). e) The schematic diagram of charge transport in conventional rGO/TiO2 stacking film.

TiO2-NP loading ensures the generation of enough electrons and holes under irradiation with UV light. In addition, the good connection between rGO sheets and TiO2-NPs (Figure S4a, Supporting Information) is beneficial to capture and transport electrons generated from TiO2-NPs irradiated by UV light to the rGO network. Furthermore, compared to conventional rGO/TiO2 electrodes, in which most connections between overlapped rGO/TiO2-NP sheets are TiO2-TiO2 contacts and not continuous (Figure 3e),[60–62,68] continuous rGO network in GHAs (Figure 1e) can transport the electrons to current collector more easily, as depicted in Figure 3a,b.[62] It improves the overall photoconversion efficiency of rGO/TiO2-NP hybrid architectures. However, when too many TiO2-NPs (Rm(TiO2: rGO) > 5) were embedded in the GHAs, the continuous crosslinking in some regions of rGO network are broken (Figure S7, Supporting Information). Hence, the electrons cannot be transported in the network in time and the majority of electrons and holes suffered from recombination, leading to the decrease of photocurrent, as shown in Figure 3d.[61] As another example, rGO/PANI-NFs hybrid architectures prepared by the hydrothermal co-assembly were applied as the high performance supercapacitor electrodes by optimizing the synergistic effects between rGO and PANI-NFs. rGO architectures are usually used as high-power supercapacitor electrodes because of their good electrical conductivity and readily accessible surface area.[6,70,71] Also, the addition of conductive polymers into the rGO architectures can effectively improve their energy density due to the pseudocapacitance originating from conducting polymers.[23] Therefore, rGO/PANI-NF hybrid architectures can be used as supercapacitor electrodes since they possess porous structure, uniform PANI-NF distribution and large PANI-NF content, as shown in Figure S8, Supporting Information.

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Pure rGO and rGO/PANI-NF hybrid architectures were cut into slices to be directly used as both electrodes of supercapacitors, as depicted in the inset of Figure 4a. Two pairs of redox waves are observed in the cyclic voltammetry (CV) curves of supercapacitor based on rGO/PANI-NF hybrid architectures (Figure 4a). These redox peaks are attributed to the redox of PANI-NFs, corresponding to their leucoemeraldine/emeraldine and emeraldine/pernigraniline structural conversions, respectively.[23] It is different from the rectangular shape of supercapacitor based on pure rGO architectures (Figure 4a), which indicates the electrical double layer performance of pure rGO architecture electrodes.[72–76] In addition, it is noted that the IR drop of supercapacitor based on rGO/PANI-NF hybrid architectures is almost negligible and much smaller than that of supercapacitor based on PANI-NF film, as shown in Figure 4b. Therefore, the unique continuous network of rGO sheets in GHAs effectively reduces the inter resistance of supercapacitor based on rGO/PANI-NF hybrid architectures during the charge/discharge process.[76,77] When the mass ratio of PANI-NFs to rGO (Rm(PANI : rGO)) is 7.5, the specific capacitance of the rGO/PANI-NF hybrid architecture is 475 F g−1, which is much larger than pure rGO architecture (162 F g−1), pure PANI-NF electrode (214 F g−1) and multilayered rGO/PANI-NF film (210 F g−1).[23] This suggests that the specific capacitance of the rGO/PANI-NF hybrid architecture is remarkably enhanced owing to the synergic effect from PANI-NFs and rGO (Figure 4c and Figure S9, Supporting Information).[23] In order to study the stability of supercapacitors based on rGO/PANI-NF hybrid architectures with different PANI-NF contents, these supercapacitors were examined by galvanostatic charge/discharge measurements for 1000 cycles, as shown in Figure 4d. With an increase of the PANI-NF content in rGO/PANI-NF hybrid architectures, more

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COMMUNICATION Figure 4. a) CV curves of supercapacitors based on pure rGO architecture, pure PANI-NF film and rGO/PANI-NF hybrid architecture (Rm(PANI : rGO) = 7.5), scan rate: 10 mV s−1. Inset is the configuration of supercapacitor based on rGO/PANI-NF hybrid architecture. b) Charge/discharge curves of supercapacitors based on pure rGO architecture, pure PANI-NF film and rGO/PANI-NF hybrid architecture (Rm(PANI : rGO) = 7.5) at a current of 1 A g−1. c) Specific capacitances of rGO/PANI-NF hybrid architectures under different Rm(PANI : rGO). d) Variation of capacitance stability with cycle number of rGO/PANI-NF hybrid architectures under different Rm(PANI : rGO).

performance degradation is observed (Figure 4d). Compared to the initial maximum capacity, there is approximately 14% drop in the capacitance after 1000 cycles for the rGO/PANINF hybrid architecture with Rm(PANI : rGO) of 7.5 due to the swelling and shrinkage of PANI-NFs.[77] However, it is still better than previous rGO/PANI hybrid electrodes,[78,79] indicating that the performance degradation of the rGO/PANI-NF hybrid architectures could be meliorated by their unique structure, to some extent. In summary, a one-step hydrothermal co-assembly method, which is environment-friendly and scalable, was developed to prepare 3D porous GHAs decorated with various nanomaterials. One key point for this method is that GO sheets in aqueous suspension can be used as surfactant to disperse various nanostructured materials to yield stable colloidal suspensions. With this method, the mass of additive nanomaterials in the composite architectures can be exactly controlled. In addition, several nanomaterials with distinctively different sizes, compositions, shapes, and properties can be simultaneously co-assembled with GO into one GHA with the controllable weight contents. Finally, as a proof of concept, the GHAs based on TiO2-NPs and PANI-NFs were used as electrodes of photoelectrochemical and supercapacitor devices, respectively, and high performance was achieved in both cases after optimizing the mass ratio. Therefore, the universality and ease of the hydrothermal co-assembly could make it a promising route to design high performance graphene hybrid materials for the applications in energy storage and conversion,

Adv. Mater. 2014, DOI: 10.1002/adma.201400143

environmental sensing and remediation, photocatalysis, and so on.

Supporting Information Supporting Information is available from the Wiley Online Library or from the author.

Acknowledgements This work was supported by the Singapore National Research Foundation (Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE) Programme and NRF-RF2009-04). Received: January 10, 2014 Revised: January 28, 2014 Published online:

[1] Z. P. Chen, W. C. Ren, L. B. Gao, B. L. Liu, S. F. Pei, H. M. Cheng, Nat. Mater. 2011, 10, 424. [2] Z. Q. Niu, J. Chen, H. H. Hng, J. Ma, X. D. Chen, Adv. Mater. 2012, 24, 4144. [3] X. W. Yang, J. W. Zhu, L. Qiu, D. Li, Adv. Mater. 2011, 23, 2833. [4] Z. S. Wu, A. Winter, L. Chen, Y. Sun, A. Turchanin, X. L. Feng, K. Müllen, Adv. Mater. 2012, 24, 5130. [5] J. Biener, S. Dasgupta, L. H. Shao, D. Wang, M. A. Worsley, A. Wittstock, J. R. I. Lee, M. M. Biener, C. A. Orme, S. O. Kucheyev,

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wileyonlinelibrary.com

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www.MaterialsViews.com

[6] [7] [8] [9] [10] [11]

[12] [13] [14] [15] [16]

[17] [18] [19] [20]

[21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] [33] [34] [35] [36] [37] [38] [39] [40]

6

B. C. Wood, T. M. Willey, A. V. Hamza, J. Weissmuller, H. Hahn, T. F. Baumann, Adv. Mater. 2012, 24, 5083. Y. X. Xu, K. X. Sheng, C. Li, G. Q. Shi, ACS Nano 2010, 4, 4324. S. Y. Yin, Y. Y. Zhang, J. H. Kong, C. J. Zou, C. M. Li, X. H. Lu, J. Ma, F. Y. C. Boey, X. D. Chen, ACS Nano 2011, 5, 3831. F. Liu, T. S. Seo, Adv. Funct. Mater. 2010, 20, 1930. U. N. Maiti, J. Lim, K. E. Lee, W. J. Lee, S. O. Kim, Adv. Mater. 2014, 26, 615. Y. Xu, Z. Lin, X. Huang, Y. Wang, Y. Huang, X. Duan, Adv. Mater. 2013, 25, 5779. S. Y. Yin, Y. L. Wu, B. Hu, Y. Wang, P. Cai, C. K. Tan, D. P. Qi, L. Zheng, W. R. Leow, N. S. Tan, S. Wang, X. D. Chen, Adv. Mater. Inter. 2014, 1, 1300043. K. Ariga, A. Vinu, Y. Yamauchi, Q. M. Ji, J. P. Hill, B. Chem. Soc. Jpn. 2012, 85, 1. Z. X. Li, J. C. Barnes, A. Bosoy, J. F. Stoddart, J. I. Zink, Chem. Soc. Rev. 2012, 41, 2590. F. Q. Tang, L. L. Li, D. Chen, Adv. Mater. 2012, 24, 1504. M. A. Worsley, P. J. Pauzauskie, T. Y. Olson, J. Biener, J. H. Satcher, T. F. Baumann, J. Am. Chem. Soc. 2010, 132, 14067. J. Y. Luo, H. D. Jang, T. Sun, L. Xiao, Z. He, A. P. Katsoulidis, M. G. Kanatzidis, J. M. Gibson, J. X. Huang, ACS Nano 2011, 5, 8943. Q. M. Ji, I. Honma, S. M. Paek, M. Akada, J. P. Hill, A. Vinu, K. Ariga, Angew. Chem. Int. Ed. 2010, 49, 9737. M. F. El-Kady, V. Strong, S. Dubin, R. B. Kaner, Science 2012, 335, 1326. W. Wei, S. Yang, H. Zhou, I. Lieberwirth, X. Feng, K. Müllen, Adv. Mater. 2013, 25, 2909. S. Yin, Y. Goldovsky, M. Herzberg, L. Liu, H. Sun, Y. Zhang, F. Meng, X. Cao, D. D. Sun, H. Chen, A. Kushmaro, X. Chen, Adv. Funct. Mater. 2013, 23, 2972. C. Li, G. Q. Shi, Nanoscale 2012, 4, 5549. D. W. Wang, F. Li, J. P. Zhao, W. C. Ren, Z. G. Chen, J. Tan, Z. S. Wu, I. Gentle, G. Q. Lu, H. M. Cheng, ACS Nano 2009, 3, 1745. Q. Wu, Y. X. Xu, Z. Y. Yao, A. R. Liu, G. Q. Shi, ACS Nano 2010, 4, 1963. S. J. Guo, S. J. Dong, E. W. Wang, ACS Nano 2010, 4, 547. D. S. Yu, L. M. Dai, J. Phys. Chem. Lett. 2010, 1, 467. D. Q. Wu, F. Zhang, H. W. Liang, X. L. Feng, Chem. Soc. Rev. 2012, 41, 6160. L. Estevez, A. Kelarakis, Q. M. Gong, E. H. Da’as, E. P. Giannelis, J. Am. Chem. Soc. 2011, 133, 6122. J. L. Vickery, A. J. Patil, S. Mann, Adv. Mater. 2009, 21, 2180. J. Du, X. Y. Lai, N. L. Yang, J. Zhai, D. Kisailus, F. B. Su, D. Wang, L. Jiang, ACS Nano 2011, 5, 590. Z. J. Fan, J. Yan, L. J. Zhi, Q. Zhang, T. Wei, J. Feng, M. L. Zhang, W. Z. Qian, F. Wei, Adv. Mater. 2010, 22, 3723. H. P. Cong, X. C. Ren, P. Wang, S. H. Yu, ACS Nano 2012, 6, 2693. Z. H. Tang, S. L. Shen, J. Zhuang, X. Wang, Angew. Chem. Int. Ed. 2010, 49, 4603. Y. Wang, Y. P. Wu, Y. Huang, F. Zhang, X. Yang, Y. F. Ma, Y. S. Chen, J. Phys. Chem. C 2011, 115, 23192. H. Bai, K. X. Sheng, P. F. Zhang, C. Li, G. Q. Shi, J. Mater. Chem. 2011, 21, 18653. Y. X. Xu, Q. O. Wu, Y. Q. Sun, H. Bai, G. Q. Shi, ACS Nano 2010, 4, 7358. W. F. Chen, S. R. Li, C. H. Chen, L. F. Yan, Adv. Mater. 2011, 23, 5679. C. Wu, X. Y. Huang, G. L. Wang, L. B. Lv, G. Chen, G. Y. Li, P. K. Jiang, Adv. Funct. Mater. 2013, 23, 403. J. H. Fendler, Chem. Mater. 2001, 13, 3196. H. Bai, C. Li, G. Q. Shi, Adv. Mater. 2011, 23, 1089. S. Y. Yin, Z. Q. Niu, X. D. Chen, Small 2012, 8, 2458.

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[41] D. H. Wang, R. Kou, D. Choi, Z. G. Yang, Z. M. Nie, J. Li, L. V. Saraf, D. H. Hu, J. G. Zhang, G. L. Graff, J. Liu, M. A. Pope, I. A. Aksay, ACS Nano 2010, 4, 1587. [42] Y. W. Cheng, S. T. Lu, H. B. Zhang, C. V. Varanasi, J. Liu, Nano Lett. 2012, 12, 4206. [43] L. J. Cote, J. Kim, V. C. Tung, J. Y. Luo, F. Kim, J. X. Huang, Pure Appl. Chem. 2011, 83, 95. [44] J. Kim, L. J. Cote, F. Kim, W. Yuan, K. R. Shull, J. X. Huang, J. Am. Chem. Soc. 2010, 132, 8180. [45] J. Kim, L. J. Cote, J. X. Huang, Acc. Chem. Res. 2012, 45, 1356. [46] V. C. Tung, J. H. Huang, I. Tevis, F. Kim, J. Kim, C. W. Chu, S. I. Stupp, J. X. Huang, J. Am. Chem. Soc. 2011, 133, 4940. [47] Y. Q. Dai, Y. Jing, J. Zeng, Q. Qi, C. L. Wang, D. Goldfeld, C. H. Xu, Y. P. Zheng, Y. M. Sun, J. Mater. Chem. 2011, 21, 18174. [48] D. R. Dreyer, S. Park, C. W. Bielawski, R. S. Ruoff, Chem. Soc. Rev. 2010, 39, 228. [49] J. B. Liu, S. H. Fu, B. Yuan, Y. L. Li, Z. X. Deng, J. Am. Chem. Soc. 2010, 132, 7279. [50] X. M. Geng, L. Niu, Z. Y. Xing, R. S. Song, G. T. Liu, M. T. Sun, G. S. Cheng, H. J. Zhong, Z. H. Liu, Z. J. Zhang, L. F. Sun, H. X. Xu, L. Lu, L. W. Liu, Adv. Mater. 2010, 22, 638. [51] X. Wang, G. Meng, C. Zhu, Z. Huang, Y. Qian, K. Sun, X. Zhu, Adv. Funct. Mater. 2014, 23, 5771. [52] R. Muszynski, B. Seger, P. V. Kamat, J. Phys. Chem. C 2008, 112, 5263. [53] Y. T. Chen, F. Guo, A. Jachak, S. P. Kim, D. Datta, J. Y. Liu, I. Kulaots, C. Vaslet, H. D. Jang, J. X. Huang, A. Kane, V. B. Shenoy, R. H. Hurt, Nano Lett. 2012, 12, 1996. [54] Y. F. Li, H. Q. Yu, H. Li, C. G. An, K. Zhang, K. M. Liew, X. F. Liu, J. Phys. Chem. C 2011, 115, 6229. [55] D. Li, M. B. Muller, S. Gilje, R. B. Kaner, G. G. Wallace, Nat. Nanotechnol. 2008, 3, 101. [56] K. Ariga, Y. Yamauchi, T. Mori, J. P. Hill, Adv. Mater. 2013, 25, 6477. [57] K. Ariga, Y. Yamauchi, G. Rydzek, Q. Ji, Y. Yonanmine, K. C.-W. Wu, J. P. Hill, Chem. Lett. 2014, 43, 36. [58] W. J. Hong, H. Bai, Y. X. Xu, Z. Y. Yao, Z. Z. Gu, G. Q. Shi, J. Phys. Chem. C 2010, 114, 1822. [59] C. Z. Zhu, S. J. Guo, P. Wang, L. Xing, Y. X. Fang, Y. M. Zhai, S. J. Dong, Chem. Commun. 2010, 46, 7148. [60] C. Chen, W. M. Cai, M. C. Long, B. X. Zhou, Y. H. Wu, D. Y. Wu, Y. J. Feng, ACS Nano 2010, 4, 6425. [61] N. J. Bell, H. N. Yun, A. J. Du, H. Coster, S. C. Smith, R. Amal, J. Phys. Chem. C 2011, 115, 6004. [62] Y. H. Ng, I. V. Lightcap, K. Goodwin, M. Matsumura, P. V. Kamat, J. Phys. Chem. Lett. 2010, 1, 2222. [63] K. F. Zhou, Y. H. Zhu, X. L. Yang, X. Jiang, C. Z. Li, New J Chem 2011, 35, 353. [64] X. Lang, X. Chen, J. Zhao, Chem. Soc. Rev. 2014, 43, 473. [65] S. Wang, L. X. Yi, J. E. Halpert, X. Y. Lai, Y. Y. Liu, H. B. Cao, R. B. Yu, D. Wang, Y. L. Li, Small 2012, 8, 265. [66] X. Y. Zhang, M. X. Sun, Y. J. Sun, J. Li, P. Song, T. Sun, X. L. Cui, Acta Phys. Chim. Sin. 2011, 27, 2831. [67] N. L. Yang, Y. Zhang, J. E. Halpert, J. Zhai, D. Wang, L. Jiang, Small 2012, 8, 1762. [68] Y. P. Zhang, C. X. Pan, J. Mater. Sci. 2011, 46, 2622. [69] K. Zheng, F. Meng, L. Jiang, Q. Yan, H. H. Hng, X. Chen, Small 2013, 9, 2076. [70] Y. Q. Sun, Q. O. Wu, G. Q. Shi, Energy Environ. Sci. 2011, 4, 1113. [71] X. W. Yang, C. Cheng, Y. F. Wang, L. Qiu, D. Li, Science 2013, 341, 534. [72] Z. Q. Niu, L. Zhang, L. Liu, B. Zhu, H. Dong, X. Chen, Adv. Mater. 2013, 25, 4035. [73] Z. Q. Niu, J. J. Du, X. B. Cao, Y. H. Sun, W. Y. Zhou, H. H. Hng, J. Ma, X. D. Chen, S. S. Xie, Small 2012, 8, 3201.

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[74] Z. Q. Niu, W. Y. Zhou, J. Chen, G. X. Feng, H. Li, Y. S. Hu, W. J. Ma, H. B. Dong, J. Z. Li, S. S. Xie, Small 2013, 9, 518. [75] Z. Q. Niu, H. B. Dong, B. W. Zhu, J. Z. Li, H. H. Hng, W. Y. Zhou, X. D. Chen, S. S. Xie, Adv. Mater. 2013, 25, 1058. [76] Z. Q. Niu, W. Y. Zhou, J. Chen, G. X. Feng, H. Li, W. J. Ma, J. Z. Li, H. B. Dong, Y. Ren, D. Zhao, S. S. Xie, Energy Environ. Sci. 2011, 4, 1440.

[77] Z. Q. Niu, P. S. Lu, Q. Shao, H. B. Dong, J. Z. Li, J. Chen, D. Zhao, L. Cai, W. Y. Zhou, X. D. Chen, S. S. Xie, Energy Environ. Sci. 2012, 5, 8726. [78] X. C. Dong, J. X. Wang, J. Wang, M. B. Chan-Park, X. G. Li, L. H. Wang, W. Huang, P. Chen, Mater. Chem. Phys. 2012, 134, 576. [79] Z. X. Tai, X. B. Yan, Q. J. Xue, J. Electrochem. Soc. 2012, 159, A1702.

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A universal strategy to prepare functional porous graphene hybrid architectures.

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