Experimental section

Commercial zeolites in their ammonium form were purchased from Zeolyst International (CBV2314, CBV3024E, CBV5524G, and CBV8014 with SiO2/Al2O3 = 23, 30, 50, and 80, respectively). The zeolites were calcination at 550 °C for 10 h using a 5 °C/min ramp to obtain the protonic form (HZSM-5) used for adsorption and reaction testing.

Na-form ZSM-5 was obtained through repeated ion exchanges of commercial ZSM-5 (CBV2314). H-form zeolite (0.1 g) was added to 50 mL 0.1 M NaCl solution, vortex mixed to disperse, and ion-exchanged overnight at 60 °C. The mixture was then separated by centrifugation at 5,000 RPM for 15 min, the liquid was replaced by fresh NaCl solution, and

the ion-exchange was repeated. A total of 3 exchanges were performed to assure a complete replacement of H+ _{by Na}+_.

Silicalite, the Al-free analog of ZSM-5, was synthesized using a gel with the following molar composition:

25 TEOS : 9 TPAOH : 480 H2O

where TEOS = tetra-n-ethylorthosilicate (Sigma-Aldrich, 98%) and TPAOH = tetra-n- propylammonium hydroxide (40 wt%, Alfa Aesar). Water and TPAOH were mixed and stirred for 5 min at 500 RPM. The TEOS was then added and the solution was stirred at 500 RPM for 1 h. The gel was then loaded into a Teflon-lined Paar 4744 stainless steel autoclave and placed in an oven at 95 °C for 48 h. Following synthesis, zeolite crystals were collected by centrifugation at 5,000 RPM for 15 min and washed twice with DI water and once with ethanol. After the final washing, the slurry was dried at 70 °C overnight. The sample was then calcined at 550 °C for 10 h using a 5 °C/min ramp to decompose the TPA structure directing agent.

Hierarchical ZSM-5 was synthesized using a dual template method reported by Emdadi et al.[31] The synthesis recipe was as follows: 30 Na2O : 1 Al2O3 : 100SiO2 : 10 C22−6−6 : 3TPAOH : 4000 H2O : 18 H2SO4, where C22−6−6 stands for the polyquaternary ammonium surfactant template, [C22H45−N+_{(CH3)2−C6H12−N}+_{(CH3)2−C6H13]Br2. The C22-6-6 template was} prepared using the method reported by Ryoo and co-workers.[32] The hydrothermal synthesis of the hierarchical ZSM-5 was performed by dissolving 1.4 g NaOH (Sigma Aldrich, ≥ 97.0%) in 6.13 g DI water, dissolving 0.8 g H2SO4 (Sigma Aldrich, 98.0%) in 8.4 g DI water, and subsequently adding the basic solution dropwise to the acidic solution under vigorous stirring. After cooling to ambient temperature, Al2(SO4)3·16H2O (Mallinckrodt Chemicals,

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98.0−102.0%) was dissolved in the mixture. TPAOH and TEOS were then added sequentially to the mixture and the mixture was stirred vigorously at room temperature for 20 h using a magnetic stirrer. Finally, the mixture was mixed with a C22−6−6 solution that was prepared by dissolving 4.4 g C22−6−6 in 30 g DI water at 60 C. After continuously mixing for 2 h at room temperature, the resultant gel was transferred into a Teflon-lined stainless-steel autoclave, followed by crystallization for 5 days by rotating Teflon lined steel autoclaves at 150 C. After crystallization, the zeolite product was filtered, washed with DI water, and dried at 70 C overnight. The zeolite sample was calcined in dry air (1.67 mL s−1_{, ultrapure, Airgas) by} increasing the temperature from ambient temperature to 600 at 0.0242 C s−1 _{and holding for} 6 h. The as-calcined zeolite sample was ion-exchanged three times using 1 M aqueous NH4NO3 (weight ratio of zeolite to NH4NO3 solution = 1:10) at 80 C for 12 h, and subsequently collected by centrifugation, washed with deionized water three times, and dried at 70 C overnight. The zeolite sample in the NH4+ _{form was treated in dry air (1.67 mL s}−1_{, ultrapure,} Airgas) by increasing the temperature from ambient temperature to 600 at 0.0242 C s−1 _and holding for 4 h to thermally decompose NH4+ _{to NH3 and H}+ _{to form the hierarchical ZSM-5} in the proton form.

4.2.2 Model compound adsorption

Phenol was selected as a representative model compound for biomass. Experimentally, phenol also presents the advantage of being solid at room temperature, allowing for physical mixtures with ZSM-5, and of being soluble in water, which facilitates its adsorption in the pores of the zeolite. Adsorption was carried out with either 0.10 or 1.00 g of phenol and 1.00 g of ZSM-5 in 200 mL of deionized water. A 1:1 phenol-to-zeolite ratio for adsorption was

used when a 1:10 ratio provided too low a carbon loading. The mixture was stirred at 500 RPM overnight. Following adsorption, the solution was centrifuged at 5000 RPM for 15 min and the liquid decanted. The solid product was then dried overnight at 60 °C to obtain the reaction starting material.

4.2.3 Catalyst characterization

Pre-reaction and post-reaction samples were analyzed for carbon loading and solid product, respectively, using an Elemantar vario MICRO cube. Approximately 5 mg of sample and an equal weight of tungsten (VI) oxide to promote combustion were loaded into a tin weigh boat and analyzed. The equipment was calibrated using rice flour prior to each analysis. Tabulated values for the carbon loading for all samples can be found in Table S1.

Ammonia temperature programmed desorption (NH3-TPD) was performed using a Micromeritics Autochem II 2920. In a typical experiment, 50 mg of zeolite powder was first heated to 550 °C using a 10 °C/min ramp and held for 1 hr to remove moisture. The zeolite was cooled and saturated with NH3 for 30 min at 50 °C using 20 ml/min of 10 vol% NH3 in He. The sample was then purged at 100 °C under flowing He for 30 min to remove weakly adsorbed ammonia. Desorption was recorded using a thermal conductivity detector (TCD) while heating from 100 °C to 700 °C at 10 °C/min. TCD curves were normalized using sample mass.

Powder X-ray diffraction measurements were performed to verify the crystallographic structure of the synthesized materials. The analysis was carried out with a Siemens D 500 diffractometer using CuKα radiation, a diffracted-beam monochromator (graphite), and a scintillation detector. A step size of 0.05° in the range of 2θ = 5 – 50° was used with a 3 s dwell

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time per step. Prior to analysis, the zeolite was mixed using mortar and pestle with a high purity corundum (Alfa Aesar, verified using NIST 674b standards zincite, rutile, and cerianite) to obtain a 40 wt% internal standard by mass mixture. All data were analyzed using Jade software version 9.5.

4.2.4 Catalytic fast pyrolysis tests

Pyrolysis experiments were carried out using a Frontier micropyrolyzer. A detailed description of the set-up can be found in previous studies.[9, 33] All tests were performed using the in-situ pyrolysis configuration, where catalyst and feedstock are co-pyrolyzed. Cellulose powder (20 µm) and phenol (ACS reagent, >99.0%) were purchased from Sigma- Aldrich. Lignin separated by the plantrose process was provided by Renmatix. A 20:1 catalyst- to-feedstock ratio was used for all physical mixtures. Reactions were carried out using 5 mg of sample at 500 °C with a 50 ml/min He carrier gas flowrate. Results are presented as molar carbon yield or the ratio of moles of carbon in the product to moles of carbon in the pre-reaction sample.

4.2.5 Diffusion measurements

Diffusion measurements were carried out in the Frontier micropyrolyzer described above but directly connected to the FID detector of the gas chromatograph following a procedure presented elsewhere.[34] The volatile products released in the reaction zone travelled through a 500 mm long inert capillary column (Agilent Technologies, 160-2845-5) until reaching the FID. Experiments were performed at 200 or 500 °C using 2 mg sample loaded into deactivated stainless steel cups. The cups were dropped into the furnace where a helium carrier gas at 100 ml/min was used to sweep the desorbed phenol and carry it to the FID for detection. The split ratio was 100:1. The maximum from each curve was taken as time

zero and the subsequent curve fit accordingly. Only the initial region was analyzed (T < 25 s) to assure the observed response was dominated by desorption kinetics. The data points were recorded every 0.1s to capture the dynamics of the product evolution.