1 Introduction
2 Direct templates
2.1 Hydrothermal synthesis
Fig.1 Summary of zeolites using ordered porous carbon as templates via HTS process: (a) Scanning electron microscopy (SEM) image of the agglomerate of close-packed spheres with high silica concentration. Reprinted with permission from ref. [47], copyright 2008 Wiley. (b) SEM and (c) transmission electron microscopy (TEM) images of the sample obtained with low silica concentration. Reprinted with permission from ref. [48], copyright 2009 American Chemical Society. (d) Schematic illustration and TEM images of 3Dom-structured zeolites through multiple hydrothermal treatments. Reprinted with permission from ref. [18], copyright 2011 American Chemical Society. |
2.2 Dry gel conversion
Fig.2 Summary of TEM images of carbon templated zeolite via DGC process: (a) Hierarchical ZSM-5 using carbon black as templates. Reprinted with permission from ref. [26], copyright 2000 American Chemical Society. (b) Hierarchical silicalite-1 using CNTs as templates. Reprinted with permission from ref. [17], copyright 2001 American Chemical Society. (c) Hierarchical silicalite-1 using carbon aerogel as templates. Reprinted with permission from ref. [27], copyright 2008 Elsevier. (d) Hierarchical silicalite-1 using carbonized carbohydrates as templates. Reprinted with permission from ref. [65], copyright 2007 Wiley. |
Fig.3 Summary of three-dimensionally ordered porous structured zeolites via DGC process: (a) SEM and (d) TEM image of ordered macro-mesoporous zeolite Beta. Reprinted with permission from ref. [68], copyright 2020 Wiley. (b, e) TEM images of 3DOm carbon templated silicalite-1 single crystals. Reprinted with permission from ref. [70] copyright 2008 Nature. (c) SEM image and (f) TEM image of CMK-L templated silicalite-1 crystals. Reprinted with permission from ref. [29], copyright 2011 Elsevier. |
Tab.1 Summary of hierarchically mesoporous zeolite synthesized by additional carbon templates a) |
Zeolite | Carbon template | Gel composition molar ratio | Crystallization approach (temperature/°C, time/d) | Vmacro/meso/(cm3·g−1) | Macro/mesopore size/nm | Model reaction | Porous characteristic | Ref. |
---|---|---|---|---|---|---|---|---|
ZSM-12 | Carbon nanoparticle | 1 Na2O:1 Al2O3:150 SiO2:36 TEAOH:4500 H2O:150 C | HTS (160, 9.5) | 0.15–0.19 | 10–50 | Conversion of n-tridecane; 1,3-dimethylcyclohexane | Meso-micropores; intracrystal and disordered | [30] |
MCM-22 | Carbon nanoparticle | 9.25 NaOH:4.51 NaAlO2:4.51 H2O:50.21 HMI:100 SiO2:4.95 C | HTS (135, 7) | 0.44 | 200 | – | Macro-meso-micropores; intercrystal, disordered and interconnected | [31] |
SAPO-34 | Carbon nanoparticle | 1.0 Al2O3:1.0 P2O5:0.6 SiO2:1.5 MOR:0.5 TEAOH:60 H2O:13.5 C | HTS (180, 2) | 0.456 | – | Uptake of n-butane; methanol to olefin | Intracrystal and disordered | [32] |
SAPO-34 | CNT | 1.0 Al2O3:1.0 P2O5:0.6 SiO2:1.5 MOR:0.5 TEAOH:60 H2O:13.5 C | HTS (180, 2) | 0.364 | – | Uptake of n-butane; methanol to olefin | Intracrystal, disordered and interconnected | [32] |
ZSM-5 | CNT | 1.00/0.50/0.33 Al2O3:10 TPABr:10 Na2O:40 SiO2:7200 H2O:647 C | HTS (175, 3) | – | 20–50 | Hydroconversion of soybean oil | Meso-micropores; intracrystal, disordered and interconnected | [33] |
SAPO-34 | CNT | 1 Al2O3:1 P2O5:x TEAOH:(2−x) MOR:60 H2O:(0–10.2) C, x = 0.0, 1.0, 2.0 | HTS (190, 1) | 0.175–0.516 | – | Methanol to olefin | Intracrystal and disordered | [34] |
Beta | CNT | 2.69 Na2O: 1 Al2O3:50.76 SiO2:12.68 TEAOH:810.24 H2O (2.8 g C/gel) | HTS (170, 1) | 0.27 | 25 | Hydrocracking of vacuum gas-oil | Meso-micropores; disordered | [35] |
NaY | Carbon aerogel | 1.00 Al2O3:4.35 SiO2:2.39 (TMA)2O:0.065 Na2O:248.00 H2O | HTS (100, 9) | 1.37 | 10 | – | Meso-micropores; disordered | [37] |
ZSM-5 | Carbon aerogel | 10 Na2O:200 SiO2: 1 Al2O3:20 TPABr:1600 H2O | HTS (100, 9) | 0.2 | 11 | – | Meso-micropores; intercrystal, disordered and interconnected | [38] |
ZSM-5 | Biomass-derived carbon | 30.5 H2O:0.017 Al(OC4H9)3: 1 Si(OC2H5)4: 1 TPAOH | HTS (160, 3) | 0.13 | 12–16 | – | Meso-micropores; intracrystal, disordered and interconnected | [39] |
Beta | GO | 1.5 Na2O:Al2O3:40 SiO2:10 TEAOH:532 H2O:(4–20) C | HTS (140, 4–32) | 0.12–0.20 | 3–7 | – | Meso-micropores; intercrystal and disordered | [28] |
ZSM-5 | Hydroxylated CNT | 100 SiO2: 1 Al2O3: 1 Na2O:0.2 (TPA)2O:17 H2O:72 C | HTS (180, 3) | 0.14 | 10–35 | Cracking of tri-isopropylbenzene | Meso-micropores; intracrystal and disordered | [43] |
ZSM-5 | Carbon black oxidized by NaClO | 80 SiO2:Al2O3:7 TPA2O:1775 H2O:160400 C | HTS (170, 2) | 0.13–0.17 | 5–18 | Disproportionation of toluene | Meso-micropores; intracrystal and disordered | [44] |
ZSM-58 | CNT oxidized by HNO3 | 21 MTI:100 SiO2:1 Al2O3:3056 H2O:12 NaOH | HTS (160, 5) | 0.06 | 3–20 | Selective adsorption of propene over propane | Meso-micropores; intracrystal and disordered | [36] |
SAPO-11 | Merck carbon oxidized by HNO3 | 1.0 Al2O3:1.0 P2O5:0.4 SiO2:1.5 DPA:50 H2O (0.06 g C/gel) | HTS (200, 1) | 0.10 | – | Hydroisomerization of n-decane | Disordered | [45] |
ZSM-5 | Carbon nanoparticle | 2 Al2O3:20 TPA2O:1 Na2O:100 SiO2:200 H2O | HTS (180, 3) | 0.45 | 34.5 | Benzylation of mesitylene with benzyl alcohol | Meso-micropores; intracrystal and disordered | [46] |
Beta | 3D CMK-n | 25 SiO2:0.25 Al2O3:4.5 (TEA)2O:0.35 Na2O:330 H2O:66.9 C | HTS (100, 4) repeated 4 times | 0.3–0.58 | – | – | Meso-micropores; intracrystal, ordered and interconnected | [18] |
LTA | 3D CMK-n | 11.25 SiO2:1.8 Al2O3:13.4 (TMA)2O:0.6 Na2O:700 H2O:6.75 C | HTS (70, 0.5) repeated 6 times | 0.28–0.68 | – | – | Meso-micropores; intracrystal, ordered and interconnected | [18] |
FAU | 3D CMK-n | 10 SiO2:2.3 Al2O3:5.5 (TMA)2O:1.2 Na2O:570 H2O:6.22 C | HTS (100, 4) repeated 5 times | 0.29 | – | – | Meso-micropores; intracrystal, ordered and interconnected | [18] |
Sn-MFI | 3D CMK-n | 1 SiO2:0.008 SnO2:0.43 TPAOH:22.20 H2O:1.5 C | HTS (170, 1) repeated 3 times | 0.283 | 4–11 | Isomerization of cellulosic sugars | Meso-micropores; intracrystal, ordered and interconnected | [51] |
SAPO-34 | 3D CMK-n | 0.6 SiO2:2 TEA2O:Al2O3:2 P2O5:75 H2O:2.92 Al(OPri)3:0.189 C | HTS (180, 0.83) repeated 5 times | 0.23–0.33 | 5.5–13 | Methanol to olefin | Meso-micropores; intracrystal, ordered and interconnected | [52] |
ZSM-11 | Carbon nanoparticle | 1 Al2O3:100 SiO2:20 TBA2O:1 Na2O:200 H2O:900 C | DGC (180, 3) | 0.40 | – | Cracking and isomerization of n-hexadecane | Intracrystal and disordered | [59] |
TS-2 | Carbon nanoparticle | 1 TiO2:100 SiO2:20 TBA2O:200 H2O:900 C | DGC (180, 3) | 031/0.44 | – | Epoxidation of oct-1-ene and styrene | Intracrystal and disordered | [59] |
ZSM-5 | Carbon nanoparticle | 1 Al2O3:100 SiO2:20 TPA2O:1 Na2O:200 H2O:900 C | DGC (180, 3) | 0.40 | – | Direct NO decomposition | Intracrystal and disordered | [60] |
TS-1 | Carbon nanoparticle | 5 TBOT:312 TEOS:123 TPAOH:9722 H2O:223 C4H10O:4159 C | DGC (175, 1) | 0.26 | 20–50 | Hydroxylation of phenol and ammoxidation of methyl-ethyl ketone | Meso-micropores; intracrystal and disordered | [61] |
SAPO-34 | CNT | 1 Al2O3:1 P2O5:0.6 SiO2:6 DEA:70 H2O:0.9 C | DGC (200, 6) | 0.031 | 0–50 | Methanol to olefin | Meso-micropores; intracrystal and disordered | [63] |
Beta | OMMC | 1 TEOS:1 TPAOH:0.04 Al(OC3H7)3 | DGC (180, 3) | 0.18 | 40 | Liquid-phase Friedel-Crafts alkylation of benzene with benzyl alcohol | Marco-meso-micropores; intracrystal, ordered and interconnected | [68] |
ZSM-5 | OMMC | 0.36 TPAOH:SiO2:x Al2O3:19.2 H2O (x = 0.067, 0.040, 0.020) | DGC (180, 3) | – | 35 | Cracking of bulky 1,3,5-TIPB; methanol to olefin | Marco-meso-micropores; intracrystal, ordered and interconnected | [69] |
Silicalite-1 | 3DOm | 9 TPA2O:0.15 Na2O:50 SiO2:390 H2O:180 ethanol | DGC (180, 2) | 0.69–0.99 | 6 | – | Meso-micropores; intracrystal, ordered and interconnected | [70] |
Silicalite-1 | CMK-L | (0–2) Al(OC3H7)3:25 TPAOH:100 TEOS | DGC (170, 6) | 0.17 | 8.7 | – | Meso-micropores; intracrystal, ordered and interconnected | [29] |
a) TEAOH: tetraethyl ammonium hydroxide; HMI: hexamethyleneimine; TPABr: tetrapropylammonium bromide; TPAOH: tetrapropyl ammonium hydroxide; DPA: diphenylamine; TBOT: tetrabutyl titanate; DEA: diethanolamine; TEOS: tetraethyl orthosilicate; 1,3,5-TIPB: 1,3,5-triisopropylbenzene. |
3 Indirect templates
3.1 CMK-n-silica composites
3.2 Carbon-coated silica composites
3.3 Carbon-silica monolithic composites
Fig.4 Summary of hierarchical zeolites derived from carbon-silica composites. Top: SEM images. Bottom: TEM images. (a, e) ZSM-5 zeolite. Reprinted with permission from ref. [81], copyright 2020 Wiley. (b, f) Silicalite-1 zeolite. Reprinted with permission from ref. [85], copyright 2018 Royal Society of Chemistry. (c, g) Silicalite-1 zeolite. Reprinted with permission from ref. [91], copyright 2013 Royal Society of Chemistry. (d, h) Zeolite Beta. Reprinted with permission from ref. [92], copyright 2016 Elsevier. |
Tab.2 Summary of the crystallization of carbon-silica composites a) |
Composites | Carbon source | Structure-directing agent | Crystallization approach (temperature/°C, time/d) | Product | Vmacro/meso/(cm3·g−1) | Pore size/nm | Model reaction | Porous characteristics | Ref. |
---|---|---|---|---|---|---|---|---|---|
Al-SBA-15/CMK-3 | Furfuryl alcohol | Ethylenediamine and triethylamine | DGC (175, 3) | Mesoporous materials with MFI zeolitic characteristics | – | 9.0 | Cracking of cumene | Meso-micropores; ordered | [73] |
SBA-15/CMK-3 | Furfuryl alcohol | TPAOH | SPT (130, 2) | Silicalite-1/SBA-15 composite | 0.26 | 6 | – | Meso-micropores; ordered | [75] |
SBA-15/CMK-3 | P123 | TPABr | HTS (180, 2) | Mesoporous ZSM-5 | 0.26/0.32 | 20–40 | Methanol to propylene | Meso-micropores; ordered and interconnected | [76] |
SiO2-TiO2/C | Tween-40 | TPAOH | HTS (180, 1) | Mesoporous TS-1 | 0.29 | 2–95 | Oxidative desulfurization | Macro-meso-micropores; intracrystal and interconnected | [77] |
P127 templated SiO2/C composite | Phenol-formaldehyde resin | TPAOH | DGC (130, 3) | Mesoporous materials with silicalite-1 nanocrystal | 0.43 | 7 | – | Meso-micropores; ordered | [78] |
P127 templated SiO2/C composite | Phenol-formaldehyde resin | TPAOH | DGC (130, 3) | Mesoporous materials with ZSM-5 nanocrystal | 0.32 | 9 | – | Meso-micropores; ordered | [78] |
P123 templated SiO2/C composite | Furfuryl alcohol | TPAOH | DGC (140, 0.5) | ZSM-5 zeolites composed of linked microcrystalline units | 0.35 | 6–8 | Benzylation reaction between naphthalene and benzyl chloride | Meso-micropores | [81] |
C deposited SiO2 | Sucrose | TBAOH | HTS (180, 3) | Mesoporous ZSM-11 | 0.04 | – | – | Intracrystal and disordered | [82] |
C deposited SiO2-TiO2 | Sucrose | TPABr | HTS (170, 7) | Mesoporous TS-1 | 0.10–0.42 | 5–90 | Oxidative desulfurization | Macro-meso-micropores; Intracrystal, disordered and interconnected | [83] |
C coated SiO2 | Sucrose | TPAOH | HTS (160, 1) | Mesoporous silicalite-1 | 0.197 | 9.4 | – | Meso-micropores; intercrystal and disordered | [84] |
C coated SiO2 | Sucrose | TPAOH | HTS (160, 1) | Mesoporous ZSM-5 | 0.263 | 7.7 | Adsorption of methylene blue, acetalization of cyclohexanone | Meso-micropores; intercrystal and disordered | [84] |
C coated SiO2 | Dopamine | TPAOH | DGC (180, 0.42) | Mesoporous ZSM-5 | – | 4–10 | Cracking of isopropyl benzene | Meso-micropores; intracrystal, disordered and interconnected | [85] |
C coated SiO2 | Dopamine | TPAOH | DGC (180, 0.5) | Mesoporous ZSM-5 | 0.13–0.34 | 18 | Self-etherification of benzyl alcohol | Meso-micropores; intracrystal, disordered and interconnected | [86] |
C deposited SiO2 | CH4 flow | TBAOH | DGC (175, 1) | Mesoporous ZSM-11 | 0.28 | 6–30 | – | Meso-micropores; intracrystal and disordered | [87] |
C deposited SiO2 | CH4 flow | TEAOH | DGC (140, 6) | Mesoporous Beta | 0.26 | 7–30 | – | Meso-micropores; intracrystal and disordered | [87] |
C deposited SiO2 | CH4 flow | Seed | DGC (100, 0.75) | Mesoporous Y | 0.02 | 10–40 | – | Meso-micropores; intracrystal and disordered | [87] |
C deposited SiO2 | CH4 flow | TPAOH | DGC (180, 3) | Mesoporous ZSM-5 | 0.28–0.48 | 10–40 | Cracking and isomerization of n-octane | Meso-micropores; intracrystal and disordered | [88] |
C deposited SiO2 | Carbonaceous gas (CxHy) | TPAOH | HTS (180, 3) | Mesoporous ZSM-5 | 0.51–0.85 | 11 | – | Meso-micropores; intercrystal and disordered | [89] |
SiO2/C monolith | Glucose and resorcinol | TPAOH | HTS (160, 4) | Mesoporous silicalite-1 | 0.27 | 30 | – | Meso-micropores; intercrystal and disordered | [91] |
SiO2-Al2O3/C monolith | Glucose and resorcinol | TPAOH | HTS (160, 4) | Mesoporous ZSM-5 | 0.29 | 30 | Condensation of benzaldehyde with n-butyl alcohol; alkylation of toluene with benzyl chloride; alkylation of toluene with benzyl chloride | Meso-micropores; intercrystal and disordered | [91] |
SiO2-TiO2/C monolith | Glucose and resorcinol | TPAOH | HTS (160, 4) | Mesoporous TS-1 | 0.26 | 30 | Hydroxylation of phenol | Meso-micropores; intercrystal and disordered | [91] |
SiO2-Al2O3/C monolith | Glucose and resorcinol | TEAOH | DGC (150, 5) | Mesoporous Beta | 0.27 | 30 | Dehydration of fructose into 5-hydroxymethylfurfural | Meso-micropores; intracrystal and disordered | [92] |
SBA-15/CMK-3 | Phenol resin | TPAOH | DGC (170, 1) | Mesoporous ZSM-5 | – | 10–15 | Cracking of triisopropylbenzene | Meso-micropores; disordered | [94] |
a) SPT: solid phase transformation; TBAOH: tetrabutylammonium hydroxide. |