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Graphene-supported metal single-atom catalysts: a concise review

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  • ReceivedDec 17, 2019
  • AcceptedMar 3, 2020
  • PublishedMar 24, 2020

Abstract


Funded by

the National Natural Science Foundation of China(51502166,51881220658)

and the Scientific Research Program Funded by Shaanxi Provincial Department(17JK0130)


Acknowledgment

This work was financially supported by the National Natural Science Foundation of China (51502166 and 51881220658), and the Scientific Research Program Funded by Shaanxi Provincial Department (17JK0130).


Interest statement

The authors declare that they have no conflict of interest.


Contributions statement

Ren S wrote and revised the manuscript with support from Yu Q; Yu X, Rong P, Jiang L and Jiang J actively discussed the original idea of this review, polished the manuscript and organized the references. All authors contributed to the general discussion.


Author information

Shuai Ren was born in 1994. He is now pursuing his Master degree in the School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong, China. His research interest is the preparation of graphene materials and the development of functional devices.


Qi Yu obtained her BSc, MSc and PhD degrees from Jilin University. Now she is an associate professor at the Institute of Graphene at Shaanxi Key Laboratory of Catalysis, Shaanxi University of Technology. Her research interests include fabrication, characterization and properties of nanomaterials, including ZnO/PET-ITO, ZnO/diamond, and graphene composite structures fabricated by magnetron sputtering or hydrothermal technique.


References

[1] Thomas JM, Saghi Z, Gai PL. Can a single atom serve as the active site in some heterogeneous catalysts?. Top Catal, 2011, 54: 588-594 CrossRef Google Scholar

[2] Zhang X, Shi H, Xu BQ. Catalysis by gold: Isolated surface Au3+ ions are active sites for selective hydrogenation of 1,3-butadiene over Au/ZrO2 catalysts. Angew Chem Int Ed, 2010, 44: 7132-7135 CrossRef PubMed Google Scholar

[3] Vajda S, Pellin MJ, Greeley JP, et al. Subnanometre platinum clusters as highly active and selective catalysts for the oxidative dehydrogenation of propane. Nat Mater, 2009, 8: 213-216 CrossRef PubMed Google Scholar

[4] Turner M, Golovko VB, Vaughan OPH, et al. Selective oxidation with dioxygen by gold nanoparticle catalysts derived from 55-atom clusters. Nature, 2008, 454: 981-983 CrossRef PubMed Google Scholar

[5] Qiao B, Wang A, Yang X, et al. Single-atom catalysis of CO oxidation using Pt1/FeOx. Nat Chem, 2011, 3: 634-641 CrossRef PubMed Google Scholar

[6] Lin J, Wang A, Qiao B, et al. Remarkable performance of Ir1/FeOx single-atom catalyst in water gas shift reaction. J Am Chem Soc, 2013, 135: 15314-15317 CrossRef PubMed Google Scholar

[7] Wang A, Li J, Zhang T. Heterogeneous single-atom catalysis. Nat Rev Chem, 2018, 2: 65-81 CrossRef Google Scholar

[8] Wang L, Huang L, Liang F, et al. Preparation, characterization and catalytic performance of single-atom catalysts. Chin J Catal, 2017, 38: 1528-1539 CrossRef Google Scholar

[9] Yang XF, Wang A, Qiao B, et al. Single-atom catalysts: a new frontier in heterogeneous catalysis. Acc Chem Res, 2013, 46: 1740-1748 CrossRef PubMed Google Scholar

[10] Sahoo S, Reber AC, Khanna SN. Effect of location and filling of d-states on methane activation in single site Fe-based catalysts. Chem Phys Lett, 2016, 660: 48-54 CrossRef Google Scholar

[11] Geim AK. Graphene: status and prospects. Science, 2009, 324: 1530-1534 CrossRef PubMed Google Scholar

[12] Wu J, Pisula W, Müllen K. Graphenes as potential material for electronics. Chem Rev, 2007, 38: 718-747 CrossRef PubMed Google Scholar

[13] Su Y, Li Z, Yu Y, et al. Composite structural modeling and tensile mechanical behavior of graphene reinforced metal matrix composites. Sci China Mater, 2018, 61: 112-124 CrossRef Google Scholar

[14] Zheng S, Zeng M, Cao H, et al. Insight into the rapid growth of graphene single crystals on liquid metal via chemical vapor deposition. Sci China Mater, 2019, 62: 1087-1095 CrossRef Google Scholar

[15] Balandin AA, Ghosh S, Bao W, et al. Superior Thermal conductivity of single-layer graphene. Nano Lett, 2008, 8: 902-907 CrossRef PubMed Google Scholar

[16] Wang L, Wu B, Liu H, et al. Low temperature growth of clean single layer hexagonal boron nitride flakes and film for graphene-based field-effect transistors. Sci China Mater, 2019, 62: 1218-1225 CrossRef Google Scholar

[17] Qin J, Zhou F, Xiao H, et al. Mesoporous polypyrrole-based graphene nanosheets anchoring redox polyoxometalate for all-solid-state micro-supercapacitors with enhanced volumetric capacitance. Sci China Mater, 2018, 61: 233-242 CrossRef Google Scholar

[18] He DX, Qiu Y, Li LL, et al. Large-scale solvent-thermal synthesis of graphene/magnetite/conductive oligomer ternary composites for microwave absorption. Sci China Mater, 2015, 58: 566-573 CrossRef Google Scholar

[19] Tombros N, Veligura A, Junesch J, et al. Large yield production of high mobility freely suspended graphene electronic devices on a polydimethylglutarimide based organic polymer. J Appl Phys, 2011, 109: 093702 CrossRef Google Scholar

[20] Castro Neto AH, Guinea F, Peres NMR, et al. The electronic properties of graphene. Rev Mod Phys, 2009, 81: 109-162 CrossRef Google Scholar

[21] Chae HK, Siberio-Pérez DY, Kim J, et al. A route to high surface area, porosity and inclusion of large molecules in crystals. Nature, 2004, 427: 523-527 CrossRef PubMed Google Scholar

[22] Deng Y, Luo C, Zhang J, et al. Fast three-dimensional assembly of MoS2 inspired by the gelation of graphene oxide. Sci China Mater, 2019, 62: 745-750 CrossRef Google Scholar

[23] Ibrahim WAW, Nodeh HR, Sanagi MM. Graphene-based materials as solid phase extraction sorbent for trace metal ions, organic compounds, and biological sample preparation. Critical Rev Anal Chem, 2016, 46: 267-283 CrossRef PubMed Google Scholar

[24] Jin L, Huang L, Ren L, et al. Preparation of stable and high-efficient poly(m-phenylenediamine)/reduced graphene oxide composites for hexavalent chromium removal. J Mater Sci, 2019, 54: 383-395 CrossRef Google Scholar

[25] Park S, Lee KS, Bozoklu G, et al. Graphene oxide papers modified by divalent ions—enhancing mechanical properties via chemical cross-linking. ACS Nano, 2008, 2: 572-578 CrossRef PubMed Google Scholar

[26] Molina-García MA, Rees NV. “Metal-free” electrocatalysis: Quaternary-doped graphene and the alkaline oxygen reduction reaction. Appl Catal A-General, 2018, 553: 107-116 CrossRef Google Scholar

[27] Chen F, Yang Q, Li X, et al. Hierarchical assembly of graphene-bridged Ag3PO4/Ag/BiVO4 (040) Z-scheme photocatalyst: an efficient, sustainable and heterogeneous catalyst with enhanced visible-light photoactivity towards tetracycline degradation under visible light irradiation. Appl Catal B-Environ, 2017, 200: 330-342 CrossRef Google Scholar

[28] Chen X, Yu L, Wang S, et al. Highly active and stable single iron site confined in graphene nanosheets for oxygen reduction reaction. Nano Energy, 2016, 32: 353-358 CrossRef Google Scholar

[29] Guo S, Yuan N, Zhang G, et al. Graphene modified iron sludge derived from homogeneous fenton process as an efficient heterogeneous fenton catalyst for degradation of organic pollutants. Microporous Mesoporous Mater, 2017, 238: 62-68 CrossRef Google Scholar

[30] Sun S, Zhang G, Gauquelin N, et al. Single-atom catalysis using Pt/graphene achieved through atomic layer deposition. Sci Rep, 2013, 3: 1775 CrossRef Google Scholar

[31] Ta HQ, Zhao L, Yin W, et al. Single Cr atom catalytic growth of graphene. Nano Res, 2018, 11: 2405-2411 CrossRef Google Scholar

[32] Yan H, Cheng H, Yi H, et al. Single-atom Pd1/graphene catalyst achieved by atomic layer deposition: remarkable performance in selective hydrogenation of 1,3-butadiene. J Am Chem Soc, 2015, 137: 10484-10487 CrossRef PubMed Google Scholar

[33] Ye H, Li Y, Chen J, et al. PdCu alloy nanoparticles supported on reduced graphene oxide for electrocatalytic oxidation of methanol. J Mater Sci, 2018, 53: 15871-15881 CrossRef Google Scholar

[34] Zhao J, Deng Q, Avdoshenko SM, et al. Direct in situ observations of single Fe atom catalytic processes and anomalous diffusion at graphene edges. Proc Natl Acad Sci USA, 2014, 111: 15641-15646 CrossRef PubMed Google Scholar

[35] Liang Y, Li Y, Wang H, et al. Co3O4 nanocrystals on graphene as a synergistic catalyst for oxygen reduction reaction. Nat Mater, 2011, 10: 780-786 CrossRef PubMed Google Scholar

[36] Li Y, Wang H, Xie L, et al. MoS2 nanoparticles grown on graphene: an advanced catalyst for the hydrogen evolution reaction. J Am Chem Soc, 2011, 133: 7296-7299 CrossRef PubMed Google Scholar

[37] Scholz D, Kröcher O, Vogel F. Deactivation and regeneration of sulfonated carbon catalysts in hydrothermal reaction environments. ChemSusChem, 2018, 11: 2189-2201 CrossRef PubMed Google Scholar

[38] Wu P, Du P, Zhang H, et al. Graphyne-supported single Fe atom catalysts for CO oxidation. Phys Chem Chem Phys, 2015, 17: 1441-1449 CrossRef PubMed Google Scholar

[39] Liu X, Sui Y, Duan T, et al. CO oxidation catalyzed by Pt-embedded graphene: a first-principles investigation. Phys Chem Chem Phys, 2014, 16: 23584-23593 CrossRef PubMed Google Scholar

[40] Zhang X, Lu Z, Xu G, et al. Single Pt atom stabilized on nitrogen doped graphene: CO oxidation readily occurs via the tri-molecular Eley–Rideal mechanism. Phys Chem Chem Phys, 2015, 17: 20006-20013 CrossRef PubMed Google Scholar

[41] Deng D, Chen X, Yu L, et al. A single iron site confined in a graphene matrix for the catalytic oxidation of benzene at room temperature. Sci Adv, 2015, 1: e1500462 CrossRef PubMed Google Scholar

[42] Yan M, Hua Y, Zhu F, et al. Constructing nitrogen doped graphene quantum dots-ZnNb2O6/g-C3N4 catalysts for hydrogen production under visible light. Appl Catal B-Environ, 2017, 206: 531-537 CrossRef Google Scholar

[43] Fei H, Dong J, Arellano-Jiménez MJ, et al. Atomic cobalt on nitrogen-doped graphene for hydrogen generation. Nat Commun, 2015, 6: 8668 CrossRef PubMed Google Scholar

[44] Yoo EJ, Okata T, Akita T, et al. Enhanced electrocatalytic activity of Pt subnanoclusters on graphene nanosheet surface. Nano Lett, 2009, 9: 2255-2259 CrossRef PubMed Google Scholar

[45] Li Y, Gao W, Ci L, et al. Catalytic performance of Pt nanoparticles on reduced graphene oxide for methanol electro-oxidation. Carbon, 2010, 48: 1124-1130 CrossRef Google Scholar

[46] Zhao Y, Zhan L, Tian J, et al. Enhanced electrocatalytic oxidation of methanol on Pd/polypyrrole–graphene in alkaline medium. Electrochim Acta, 2011, 56: 1967-1972 CrossRef Google Scholar

[47] Lefèvre M, Proietti E, Jaouen F, et al. Iron-based catalysts with improved oxygen reduction activity in polymer electrolyte fuel cells. Science, 2009, 324: 71-74 CrossRef PubMed Google Scholar

[48] Stambula S, Gauquelin N, Bugnet M, et al. Chemical structure of nitrogen-doped graphene with single platinum atoms and atomic clusters as a platform for the PEMFC electrode. J Phys Chem C, 2014, 118: 3890-3900 CrossRef Google Scholar

[49] Lu Y, Liu M, Nie H, et al. Direct fabrication of metal-free hollow graphene balls with a self-supporting structure as efficient cathode catalysts of fuel cell. J Nanopart Res, 2016, 18: 160 CrossRef Google Scholar

[50] Shao Y, Zhang S, Kou R, et al. Noncovalently functionalized graphitic mesoporous carbon as a stable support of Pt nanoparticles for oxygen reduction. J Power Sources, 2010, 195: 1805-1811 CrossRef Google Scholar

[51] Nie R, Miao M, Du W, et al. Selective hydrogenation of C–C bond over N-doped reduced graphene oxides supported Pd catalyst. Appl Catal B-Environ, 2016, 180: 607-613 CrossRef Google Scholar

[52] Ahmed SN, Haider W. Heterogeneous photocatalysis and its potential applications in water and wastewater treatment: a review. Nanotechnology, 2018, 29: 342001 CrossRef PubMed Google Scholar

[53] Prasad M, Sharma V, Aher R, et al. Synergistic effect of Ag plasmon- and reduced graphene oxide-embedded ZnO nanorod-based photoanodes for enhanced photoelectrochemical activity. J Mater Sci, 2017, 52: 13572-13585 CrossRef Google Scholar

[54] Song X, Shi Q, Wang H, et al. Preparation of Pd-Fe/graphene catalysts by photocatalytic reduction with enhanced electrochemical oxidation-reduction properties for chlorophenols. Appl Catal B-Environ, 2017, 203: 442-451 CrossRef Google Scholar

[55] Cheng J, Zhang M, Wu G, et al. Photoelectrocatalytic reduction of CO2 into chemicals using Pt-modified reduced graphene oxide combined with Pt-modified TiO2 nanotubes. Environ Sci Technol, 2014, 48: 7076-7084 CrossRef PubMed Google Scholar

[56] Yoshitake T, Shimakawa Y, Kuroshima S, et al. Preparation of fine platinum catalyst supported on single-wall carbon nanohorns for fuel cell application. Physica B-Condensed Matter, 2002, 323: 124-126 CrossRef Google Scholar

[57] Jones J, Xiong H, DeLaRiva AT, et al. Thermally stable single-atom platinum-on-ceria catalysts via atom trapping. Science, 2016, 353: 150-154 CrossRef PubMed Google Scholar

[58] Allen JE, Hemesath ER, Perea DE, et al. High-resolution detection of Au catalyst atoms in Si nanowires. Nat Nanotech, 2008, 3: 168-173 CrossRef PubMed Google Scholar

[59] Kolmakov A, Klenov DO, Lilach Y, et al. Enhanced gas sensing by individual SnO2 nanowires and nanobelts functionalized with Pd catalyst particles. Nano Lett, 2005, 5: 667-673 CrossRef PubMed Google Scholar

[60] Kim HM, Kim K, Lee CY, et al. Electrical conductivity and electromagnetic interference shielding of multiwalled carbon nanotube composites containing Fe catalyst. Appl Phys Lett, 2004, 84: 589-591 CrossRef Google Scholar

[61] Blomquist J, Lång H, Larsson R, et al. Pyrolysis behaviour of metalloporphyrins. Part 2—A Mössbauer study of pyrolysed FeIII tetraphenylporphyrin chloride. J Chem Soc Faraday Trans, 1992, 88: 2007-2011 CrossRef Google Scholar

[62] Jiao L, Wan G, Zhang R, et al. From metal-organic frameworks to single-atom Fe implanted N-doped porous carbons: Efficient oxygen reduction in both alkaline and acidic media. Angew Chem Int Ed, 2018, 57: 8525-8529 CrossRef PubMed Google Scholar

[63] Liu W, Zhang L, Yan W, et al. Single-atom dispersed Co–N–C catalyst: structure identification and performance for hydrogenative coupling of nitroarenes. Chem Sci, 2016, 7: 5758-5764 CrossRef PubMed Google Scholar

[64] Wan G, Yang C, Zhao W, et al. Anion-regulated selective generation of cobalt sites in carbon: Toward superior bifunctional electrocatalysis. Adv Mater, 2017, 29: 1703436-1703443 CrossRef PubMed Google Scholar

[65] Zhu C, Shi Q, Xu BZ, et al. Hierarchically porous M-N-C (M = Co and Fe) single-atom electrocatalysts with robust MNx active moieties enable enhanced ORR performance. Adv Energy Mater, 2018, 8: 1801956-1801963 CrossRef Google Scholar

[66] Xu BQ, Wei JM, Wang HY, et al. Nano-MgO: novel preparation and application as support of Ni catalyst for CO2 reforming of methane. Catal Today, 2001, 68: 217-225 CrossRef Google Scholar

[67] Jabri A, Temple C, Crewdson P, et al. Role of the metal oxidation state in the SNS−Cr catalyst for ethylene trimerization: isolation of di- and trivalent cationic intermediates. J Am Chem Soc, 2006, 128: 9238-9247 CrossRef PubMed Google Scholar

[68] Sakthivel S, Shankar MV, Palanichamy M, et al. Enhancement of photocatalytic activity by metal deposition: characterisation and photonic efficiency of Pt, Au and Pd deposited on TiO2 catalyst. Water Res, 2004, 38: 3001-3008 CrossRef PubMed Google Scholar

[69] Stagg-Williams SM, Noronha FB, Fendley G, et al. CO2 reforming of CH4 over Pt/ZrO2 catalysts promoted with La and Ce oxides. J Catal, 2000, 194: 240-249 CrossRef Google Scholar

[70] Llorca J, de la Piscina PRı, Dalmon JA, et al. CO-free hydrogen from steam-reforming of bioethanol over ZnO-supported cobalt catalysts. Appl Catal B-Environ, 2003, 43: 355-369 CrossRef Google Scholar

[71] Abbet S, Sanchez A, Heiz U, et al. Acetylene cyclotrimerization on supported size-selected Pdn clusters (1 ≤ n ≤ 30): One atom is enough!. J Am Chem Soc, 2000, 122: 3453-3457 CrossRef Google Scholar

[72] Qiao B, Liu J, Wang YG, et al. Highly efficient catalysis of preferential oxidation of CO in H2-rich stream by gold single-atom catalysts. ACS Catal, 2015, 5: 6249-6254 CrossRef Google Scholar

[73] Zhang H, Kawashima K, Okumura M, et al. Colloidal Au single-atom catalysts embedded on Pd nanoclusters. J Mater Chem A, 2014, 2: 13498-13508 CrossRef Google Scholar

[74] Guo X, Fang G, Li G, et al. Direct, nonoxidative conversion of methane to ethylene, aromatics, and hydrogen. Science, 2014, 344: 616-619 CrossRef PubMed Google Scholar

[75] Guo S, Ma L, Song G, et al. Covalent grafting of triazine derivatives onto graphene oxide for preparation of epoxy composites with improved interfacial and mechanical properties. J Mater Sci, 2018, 53: 16318-16330 CrossRef Google Scholar

[76] Li J, Tang X, Yi H, et al. Effects of copper-precursors on the catalytic activity of Cu/graphene catalysts for the selective catalytic oxidation of ammonia. Appl Surf Sci, 2017, 412: 37-44 CrossRef Google Scholar

[77] Niu Y, Huang X, Wu X, et al. One-pot synthesis of Co/N-doped mesoporous graphene with embedded Co/CoOx nanoparticles for efficient oxygen reduction reaction. Nanoscale, 2017, 9: 10233-10239 CrossRef PubMed Google Scholar

[78] Primo A, Atienzar P, Sanchez E, et al. From biomass wastes to large-area, high-quality, N-doped graphene: catalyst-free carbonization of chitosan coatings on arbitrary substrates. Chem Commun, 2012, 48: 9254-9256 CrossRef PubMed Google Scholar

[79] Ren X, Liao B, Li Y, et al. Facile synthesis of PdSnCo/nitrogen-doped reduced graphene as a highly active catalyst for lithium-air batteries. Electrochim Acta, 2017, 228: 36-44 CrossRef Google Scholar

[80] Wang H, Xiao H, Lu Y, et al. The catalytic effect of boron nitride on the mechanical properties of polyacrylonitrile-based carbon fiber. J Mater Sci, 2016, 51: 10690-10700 CrossRef Google Scholar

[81] Wang H, Zhang X, Takamatsu H. Ultraclean suspended monolayer graphene achieved by in situ current annealing. Nanotechnology, 2017, 28: 045706 CrossRef PubMed Google Scholar

[82] Yan H, Lin Y, Wu H, et al. Bottom-up precise synthesis of stable platinum dimers on graphene. Nat Commun, 2017, 8: 1070-1081 CrossRef PubMed Google Scholar

[83] Wang T, Wang J, Wang X, et al. Graphene-templated synthesis of sandwich-like porous carbon nanosheets for efficient oxygen reduction reaction in both alkaline and acidic media. Sci China Mater, 2018, 61: 915-925 CrossRef Google Scholar

[84] Sahoo S, Suib SL, Alpay SP. Graphene supported single atom transition metal catalysts for methane activation. ChemCatChem, 2018, 10: 3229-3235 CrossRef Google Scholar

[85] Robertson AW, Montanari B, He K, et al. Dynamics of single Fe atoms in graphene vacancies. Nano Lett, 2013, 13: 1468-1475 CrossRef PubMed Google Scholar

[86] Zhang X, Guo J, Guan P, et al. Catalytically active single-atom niobium in graphitic layers. Nat Commun, 2013, 4: 1924 CrossRef PubMed Google Scholar

[87] Wang WL, Santos EJG, Jiang B, et al. Direct observation of a long-lived single-atom catalyst chiseling atomic structures in graphene. Nano Lett, 2016, 14: 450-455 CrossRef PubMed Google Scholar

[88] Yang HB, Hung SF, Liu S, et al. Atomically dispersed Ni(I) as the active site for electrochemical CO2 reduction. Nat Energy, 2018, 3: 140-147 CrossRef Google Scholar

[89] Huang ML, Chang YC, Chang CH, et al. Surface passivation of III-V compound semiconductors using atomic-layer-deposition-grown Al2O3. Appl Phys Lett, 2005, 87: 252104-252107 CrossRef Google Scholar

[90] Kim H. Atomic layer deposition of metal and nitride thin films: current research efforts and applications for semiconductor device processing. J Vac Sci Technol B, 2003, 21: 2231-2261 CrossRef Google Scholar

[91] Sneh O, Clark-Phelps RB, Londergan AR, et al. Thin film atomic layer deposition equipment for semiconductor processing. Thin Solid Films, 2002, 402: 248-261 CrossRef Google Scholar

[92] Ahn KY, Forbes L. Atomic layer deposited nanolaminates of HfO2/ZrO2 films as gate dielectrics. US Patent, 20040023461, 2007. Google Scholar

[93] Elam JW, Sechrist ZA, George SM. ZnO/Al2O3 nanolaminates fabricated by atomic layer deposition: growth and surface roughness measurements. Thin Solid Films, 2002, 414: 43-55 CrossRef Google Scholar

[94] Lim BS, Rahtu A, de Rouffignac P, et al. Atomic layer deposition of lanthanum aluminum oxide nano-laminates for electrical applications. Appl Phys Lett, 2004, 84: 3957-3959 CrossRef Google Scholar

[95] Shao Y, Zhang S, Wang C, et al. Highly durable graphene nanoplatelets supported Pt nanocatalysts for oxygen reduction. J Power Sources, 2010, 195: 4600-4605 CrossRef Google Scholar

[96] Li W, Liang C, Zhou W, et al. Preparation and characterization of multiwalled carbon nanotube-supported platinum for cathode catalysts of direct methanol fuel cells. J Phys Chem B, 2003, 107: 6292-6299 CrossRef Google Scholar

[97] Koningsberger DC, Mojet BL, van Dorssen GE, et al. XAFS spectroscopy; fundamental principles and data analysis. Top Catal, 2000, 10: 143-155 CrossRef Google Scholar

[98] Browning ND, Chisholm MF, Pennycook SJ. Atomic-resolution chemical analysis using a scanning transmission electron microscope. Nature, 1993, 366: 143-146 CrossRef Google Scholar

[99] Li C, Yang G. The principle and applications of STEM and EELS. Physics, 2014, 43: 597–605. Google Scholar

[100] Zhao W, Wan G, Peng C, et al. Key single-atom electrocatalysis in metal-organic framework (MOF)-derived bifunctional catalysts. ChemSusChem, 2018, 11: 3473-3479 CrossRef PubMed Google Scholar

[101] Greca F, Hares MM, Nevah E, et al. A randomized trial to compare rubber band ligation with phenol injection for treatment of hemorrhoids. Br J Surg, 1981, 68: 250-252 CrossRef PubMed Google Scholar

[102] Rengaraj S. Removal of phenol from aqueous solution and resin manufacturing industry wastewater using an agricultural waste: rubber seed coat. J Hazard Mater, 2002, 89: 185-196 CrossRef Google Scholar

[103] El-Naas MH, Al-Zuhair S, Alhaija MA. Removal of phenol from petroleum refinery wastewater through adsorption on date-pit activated carbon. Chem Eng J, 2010, 162: 997-1005 CrossRef Google Scholar

[104] Wagner M, Nicell JA. Peroxidase-catalyzed removal of phenols from a petroleum refinery wastewater. Water Sci Tech, 2001, 43: 253-260 CrossRef Google Scholar

[105] Lai TL, Lai YL, Lee CC, et al. Microwave-assisted rapid fabrication of Co3O4 nanorods and application to the degradation of phenol. Catal Today, 2008, 131: 105-110 CrossRef Google Scholar

[106] Pradhan GK, Padhi DK, Parida KM. Fabrication of α-Fe2O3 nanorod/RGO composite: A novel hybrid photocatalyst for phenol degradation. ACS Appl Mater Interfaces, 2013, 5: 9101-9110 CrossRef PubMed Google Scholar

[107] Iwamoto M, Hirata J, Matsukami K, et al. Catalytic oxidation by oxide radical ions. 1. One-step hydroxylation of benzene to phenol over group 5 and 6 oxides supported on silica gel. J Phys Chem, 1983, 87: 903-905 CrossRef Google Scholar

[108] Bak T, Nowotny J, Rekas M, et al. Photo-electrochemical hydrogen generation from water using solar energy. Materials-related aspects. Int J Hydrogen Energy, 2002, 27: 991-1022 CrossRef Google Scholar

[109] O'M Bockris J. On hydrogen futures: toward a sustainable energy system. Int J Hydrogen Energy, 2003, 28: 131-133 CrossRef Google Scholar

[110] Turner JA. Sustainable hydrogen production. Science, 2004, 305: 972-974 CrossRef PubMed Google Scholar

[111] Cao Y, Hu P, Pan W, et al. Methanal and xylene sensors based on ZnO nanoparticles and nanorods prepared by room-temperature solid-state chemical reaction. Sens Actuat B-Chem, 2008, 134: 462-466 CrossRef Google Scholar

[112] Watanabe M, Motoo S. Electrocatalysis by ad-atoms. J Electroanal Chem Interfacial Electrochem, 1975, 60: 267-273 CrossRef Google Scholar

[113] Liu H, Song C, Zhang L, et al. A review of anode catalysis in the direct methanol fuel cell. J Power Sources, 2006, 155: 95-110 CrossRef Google Scholar

[114] Steele BCH, Heinzel A. Materials for fuel-cell technologies. Nature, 2001, 414: 345-352 CrossRef PubMed Google Scholar

[115] Proietti E, Jaouen F, Lefèvre M, et al. Iron-based cathode catalyst with enhanced power density in polymer electrolyte membrane fuel cells. Nat Commun, 2011, 2: 416-425 CrossRef PubMed Google Scholar

[116] Kramm UI, Herrmann-Geppert I, Behrends J, et al. On an easy way to prepare metal–nitrogen doped carbon with exclusive presence of MeN4-type sites active for the ORR. J Am Chem Soc, 2016, 138: 635-640 CrossRef PubMed Google Scholar

[117] Wan G, Lin XM, Wen J, et al. Tuning the performance of single-atom electrocatalysts: support-induced structural reconstruction. Chem Mater, 2018, 30: 7494-7502 CrossRef Google Scholar

[118] Wan G, Yu P, Chen H, et al. Engineering single-atom cobalt catalysts toward improved electrocatalysis. Small, 2018, 14: 1704319-1704325 CrossRef PubMed Google Scholar

  • Figure 1

    Schematic diagram illustrating the relationships of surface free energy, instability and specific activity per metal atom on traditional supporting substrate with metal size.

  • Figure 2

    (a) HRTEM images of silicon/graphene sample, (b) catalytic principles of the single Si ad-atom. Reprinted with permission from Ref. [87], Copyright 2016, American Chemical Society.

  • Figure 3

    Preparation, morphology and compositional characterizations of the Co-NG. (a) Preparation process of the Co-NG catalyst, (b) SEM image, (c) XPS spectra (NG represents N-graphene), (d) HR XPS Co 2p and N 1s spectra. Reprinted with permission from Ref. [43], Copyright 2015, Nature Publishing Group.

  • Figure 4

    (a) Schematic diagrams of Pt ALD principle, (b) CV curves of methanol oxidation, (c) XANES spectra at Pt L3 edge. Reprinted with permission from Ref. [30], Copyright 2013, Nature Publishing Group.

  • Figure 5

    (a) Schematic diagrams of dimeric Pt2/graphene catalysts, (b) catalytic activities of diverse Pt catalysts. Reprinted with permission from Ref. [82], Copyright 2017, Springer Nature.

  • Figure 6

    TEM images (a), Raman spectrum (b) and XRD patterns (c) of graphene nanoplatelets. Reprinted with permission from Ref. [95], Copyright 2010, Elsevier.

  • Figure 7

    Pt L3-edge XAFS spectrum for platinum foil. Reprinted with permission from Ref. [97], Copyright 2000, Springer.

  • Figure 8

    (a) Coordination structure and valence state of FeN4/GN catalysts, (b) morphology analysis of FeN4/GN catalyst. Reprinted with permission from Ref. [41], Copyright 2015, American Association for the Advancement of Science.

  • Figure 9

    STEM detector distribution diagram.

  • Figure 10

    (a) HAADF-STEM images of Pd1/graphene, (b) schematic diagrams of butene selectivity on Pd1/graphene catalyst, (c) catalytic capabilities of various samples. Reprinted with permission from Ref. [32], Copyright 2015, American Chemical Society.

  • Figure 11

    (a) SEM and AFM images of single atom Ni-graphene catalyst, (b) TEM image of Ni-graphene catalyst, (c) electronic states of Ni atom in the Ni-graphene catalysts, (d) CO2 reduction in aqueous solution. Reprinted with permission from Ref. [88], Copyright 2018, Springer Nature.

  • Figure 12

    (a) The plausible theoretical calculation results for CO adsorption on PtMG, (b) the contour plot of PtMG, DOS of PtMG and Pt (111) surface. Reprinted with permission from Ref. [39], Copyright 2014, Royal Society of Chemistry.

  • Figure 13

    (a) TEM images and histogram of Pt/GNS; (b) current-potential curves for MOR on (1) Pt/carbon black, (2) Pt/GNS and (3) Pt/Ru-carbon black; (c) HAADF-STEM image of Pt/GNS. Reprinted with permission from Ref. [44], Copyright 2009, American Chemical Society.