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1 Electronic Supplementry Mteril (ESI) for ChemComm. This journl is The Royl Society of Chemistry 218 Electronic Supplementry Informtion Nitrogen-free commercil cron cloth with rich defects for electroctlytic mmoni synthesis under mient conditions Wenyi Li, Tinxing Wu, Shengo Zhng, Ynyn Liu, Cuijio Zho, Guoqing Liu, Guozhong Wng, Himin Zhng,* nd Huijun Zho c. Key Lortory of Mterils Physics, Centre for Environmentl nd Energy Nnomterils, Anhui Key Lortory of Nnomterils nd Nnotechnology, CAS Center for Excellence in Nnoscience, Institute of Solid Stte Physics, Chinese Acdemy of Sciences, Hefei 2331, Chin. E-mil: University of Science nd Technology of Chin, Hefei 2326, Chin. c. Centre for Clen Environment nd Energy, Griffith University, Gold Cost Cmpus, QLD 4222, Austrli. Experimentl section Preprtion of CC-X smples. All of the chemicl regents were nlyticl grde (AR) nd were used without further purifiction. The commercil cron cloth (CC, HCP33) ws purchsed from Shnghi HESEN compny, which ws composed of the interwoven cron fiers nd fricted t high temperture (15~18 C) in Ar tmosphere. Firstly, the commercil cron cloth (CC) ws rinsed dequtely with ethnol nd wter for severl times, then thermlly treted t different tempertures (25, 35 nd 45 ) in muffle under ir tmosphere for 2 h with heting rte of 5 min -1. After tht, the s-fricted CC smples were collected nd denoted s CC-X, in where X represents the temperture of 25, 35 nd 45, respectively. Chrcteriztion. The crystlline phse nd structure of the otined smples were chrcterized y X-ry diffrction (XRD, X'Pert Pro Super, Philips Co., the Netherlnds) with Cu K rdition ( A). The morphology nd precise structure of the smples were chrcterized y field emission scnning electron

2 microscopy (FESEM, Qunt 2FEG) nd trnsmission electron microscopy (TEM, JEOL 21) with n energy dispersive X-ry spectrometer (EDS Oxford, Link ISIS). X-ry photoelectron spectroscopy (XPS) nlysis of the smples ws performed on n ESCALAB 25(Thermo, Americ) equipped with Al Kα 1,2 monochromtized rdition t ev X-ry source. Rmn spectr of the smples were recorded on Renishw invi Rmn microspectrometer. N 2 dsorption desorption isotherms of the smples were crried out on Autosor-iQ-Cx (Quntchrome, United Sttes). Temperture-progrmmed desorption (N 2 -TPD) of N 2 experiments were conducted on Quntchrome ChemBET Pulsr TPR/TPD. Thermogrvimetric nlysis (TGA) ws crried out on Perkin-Elmer pprtus (Pyris 1) t heting rte of 5 min -1 from room temperture to 7 in flowing ir. Electrochemicl mesurements. All electrochemicl mesurements were performed on CHI 76E electrochemicl worksttion (CH Instrumentl Corportion, Shnghi, Chin). All experiments were performed in seled single-comprtment rector with configurtion composed of the thermlly treted cron cloth (CC, 1 1 cm 2 ) working electrode, Ag/AgCl reference electrode nd pristine CC (1 1 cm 2 ) counter electrode. The polriztion curves were mesured with scn rte of 5. mv s 1 t room temperture nd ll polriztion curves were otined t the stedy-stte ones fter severl cycles. The electrochemicl impednce spectroscopy (EIS) mesurements were performed y pplying n AC voltge with 1 mv mplitude in frequency rnge from 1, to 1 Hz nd recorded t -.3 V (vs. RHE). For N 2 reduction rection (NRR) experiments, the potentiosttic test ws conducted for 1 h

3 under the N 2 -sturted.1 M N 2 SO M H 2 SO 4 solution (2 ml) y continuously supplying N 2 into the electrolyte under mient conditions. Determintion of mmoni. Concentrtion of the produced mmoni ws spectrophotometriclly detected y the indophenol lue. In detil,5 ml of smple ws tken, nd then diluted with 5 ml of deionized wter. Susequently, 1 μl of oxidizing solution (sodium hypochlorite (ρcl=4~4.9) nd.75 M sodium hydroxide), 5 μl of colouring solution (.4 M sodium slicylte nd.32 M sodium hydroxide) nd 1 μl of ctlyst solution (.1g N 2 [Fe(CN) 5 NO] 2H 2 O diluted to 1 ml with deionized wter) were dded respectively to the mesured smple solution. After the plcement of 1 h in room temperture, the sornce mesurements were performed t wvelength of 697 nm. The otined clirtion curve (Fig. S4) ws used to clculte the mmoni concentrtion. Determintion of hydrzine. The hydrzine present in the electrolyte ws estimted y the of Wtt nd Chrisp. A mixture of pr-(dimethylmino) enzldehyde (5.99 g), HCI (concentrted, 3 ml) nd ethnol (3 ml) ws used s color regent. In detil,5 ml of smple with.1 M HCl solution ws tken, nd then 5 ml of the prepred color regent ws dded to the ove smple solution. Susequently, the sornce mesurements were performed fter the plcement of 2 min t wvelength of 455 nm. The otined clirtion curve (Fig. S5) ws used to clculte the N 2 H 4 H 2 O concentrtion. Clcultions of NH 3 production rte nd Frdic efficiency. The eqution of NH 3 production rte:

4 -3-1 ( -2-1 (ppm) 1 (g mg ) V (L) R NH3)(mol cm s ) 1 - Mr (g mol ) t(s) S(cm 2 ) NH4 N where R(NH 3 ) is the mmoni production rte in mol cm -2 s -1 ; χ (ppm) is the produced mmoni concentrtion; V (L) is the electrolyte solution volume; Mr NH4 + - N=14 (g mol -1 ); t (s) is the rection time; S is the geometric re of the cthodic electrode in cm -2, nd in this work two sides of the cron cloth electrode re electroctlyticlly ctive for the NRR, thus the NH 3 production rte is clculted y dividing the totl geometric re of two sides of the cron cloth electrode. The eqution of Frdic efficiency: -2 3 R(NH3)(mol cm s FE(NH )(%) Q ) S(cm ) F % where F is the Frdic constnt ( ); Q is the totl chrge during the NRR. Supplementry Tles nd Figures Tle S1. Elementl composition nlysis of the pristine CC nd CC-X smples y XPS technique. Smple C (t.%) O (t.%) Pristine CC CC-25 CC-35 CC

5 Tle S2. The comprle results of our work nd other recently reported cronsed NRR electroctlysts. References Ctlyst System NH 3 Production Rte Frdic Detection /Conditions Efficiency (%) Angew. Chem. Int. Ed. 217, 56, Adv. Mter. 217, 29, Fe 2 O 3 -CNTs KHCO g NH3 m -2 h -1 (-2.V vs. Ag/AgCl) Au nnorods.1 M KOH g h -1 cm -2 (-.2 V vs. RHE).15 Indophenol 3.87 Nesslers regent ACS Ctl. N doped porous.5 M H 2 SO mmol g 1 h Nesslers 218, 8, cron (-.9 V vs. RHE) regent Nno Energy ZIF-derived.1 M KOH mol cm 2 h Indophenol 218, 48, 217. cron (-.3V vs. RHE) Nt. Commun. 218, 9, Adv. Mter. 218, Pd/C.1 M PBS 4.5 μg mg 1 Pd h 1 (.1V vs. RHE) MoS 2 /CC.1 M N 2 SO mol s 1 cm 1 (-.2 V vs. RHE) 8.2 Indophenol 1.17 Indophenol Sci. Adv. N doped cron.25 M ± 7.13 mg h 1 cm ±.85 Indophenol 218, 4: e nnospikes LiClO 4 (-1.19 V vs. RHE) Chem. Commun. 218, 54, VN/CC.1 M HCl mol s 1 cm 1 (-.3 V vs. RHE) 3.58 Indophenol J. Mter. Chem. A N doped porous.1 M HCl 15.7 μg h -1 mg Indophenol 218, 6, cron (-.3 V vs. RHE) Angew. Chem. Int. Ed. N doped porous 1. M HCl.8 g h 1 m Indophenol 218, 57, 1. cron (-.3 V vs. RHE) ACS Energy Lett. α-fe@fe 3 O 4 [C 4 mpyr][efap] mol s 1 cm 2 32 Indophenol 218, 3, FPEE mix (-.6 V vs. NHE) Energy Environ. Sci. Fe [P 6,6,6,14 ][efap] 14 mg h 1 m 2 6 Indophenol 217, 1, electrode/fto (-.8 V vs. NHE) This work CC-45.1 M N 2 SO M H 2 SO mol s 1 cm 1 or mol cm 2 h 1 or 15.8 μg cm -1 h -1 (-.3 V vs. RHE) 6.92 Indopheno l

6 3 µm 4 µm c d 3 µm 4 µm Fig. S1 Low- nd high-mgnifiction SEM imges of (), () the pristine CC nd (c), (d) the thermlly treted CC-45.

7 C1s O1s Pristine CC Intensity(.u.) CC-25 CC-35 CC Fig. S2 The surfce survey XPS spectr of the pristine CC nd CC-X smples. Intensity(.u.) Intensity(.u.) c d Intensity(.u.) Intensity(.u.) Fig. S3 The high-resolution XPS spectr of () the pristine CC; () CC-25; (c) CC-35; (d) CC-45 smples efore the NRR.

8 C 1s O 1s Intensity(.u.) Intensity(.u.) c C 1s d O 1s Intensity(.u.) Intensity(.u.) e C 1s f O 1s Intensity(.u.) Intensity(.u.) Fig. S4 The high-resolution C 1s nd O 1s XPS spectr of (),() pristine CC; (c), (d) CC-25; (e), (f) CC-35.

9 Asornce (.u) Asornce (.u.) y= x R 2 = Wvelength (nm) NH 4 + -N (μg ml -1 ) Fig. S5 () UV-Vis sorption spectr of vrious NH 4+ -N concentrtions (,.1,.2,.4,.6 nd.8 μg ml -1 ) fter incuted for 1 h t room temperture. () The clirtion curve used for clcultion of NH 4+ -N concentrtion; the inset in () of the corresponding photogrphs of different concentrtions of NH 4+ -N solutions. Asornce (.u) Asornce (.u.) y= x R 2 = Wvelength (nm) N 2 H 4 H 2 O (μg ml -1 ) Fig. S6 () UV-Vis sorption spectr of vrious N 2 H 4 H 2 O concentrtions (,.5, 1, 2, 4 nd 6 μg ml -1 ) fter incuted for 2 min t room temperture. () The clirtion curve used for clcultion of N 2 H 4 H 2 O concentrtions. The inset in () of the corresponding photogrphs of different concentrtions of N 2 H 4 H 2 O solutions.

10 Current Density (ma cm -2 ) CC-45O CC-35O CC-25O Pristine CC LSV-N 2 LSV-Ar E (V vs. RHE) Fig. S7 Liner sweep voltmmogrm (LSV) curves of the pristine CC nd thermlly treted CC electroctlysts in Ar- or N 2 -sturted.1 M N 2 SO M H 2 SO 4 electrolyte with scn rte of 5. mv s 1. Current Density (ma cm -2 ) V -.6 V V -.8 V -.9 V -1. V Time (s) Fig. S8 Time-dependent current density curves of () pristine CC nd () CC-45 for the NRR t different potentils in.1 M N 2 SO M H 2 SO 4 electrolyte. Current Density (ma cm -2 ) V -.3 V V -.5 V -.6 V Time (s)

11 Current Density(mA cm -2 ) 1-1 Current Density(mA cm -2 ) Time(h) Time(h) 8 1 Fig. S9 The current density-time curves of the CC-45 t -.3 V (vs. RHE) in N 2 - sturted.1 M N 2 SO M H 2 SO 4 electrolyte for two times 1 h of NRR mesurements. () First durility test; () Second durility test. NH 3 Yield (μg ml -1 ) First durility test Second durility test Time (h) Fig. S1 The NH 3 yield otined t -.3 V (vs. RHE) in N 2 -sturted.1 M N 2 SO M H 2 SO 4 electrolyte for two times 1 h of NRR mesurements.

12 Intensity(.u.) ev Pyridinic N 4.1 ev Pyrrolic N 41.2 ev Grphitic N Intensity(.u.) ev Pyridinic N 4.1 ev Pyrrolic N 41.2 ev Grphitic N c Intensity(.u.) ev Pyridinic N 4.1 ev Pyrrolic N 41.2 ev Grphitic N d Intensity(.u.) ev Pyridinic N 4.1 ev Pyrrolic N 41.2 ev Grphitic N Fig. S11 The high-resolution XPS spectr of () pristine CC; () CC-25; (c) CC-35; (d) CC-45 smples fter the NRR for 1 h of rection.

13 Asornce Wvelength(nm) Fig. S12 UV-Vis spectr of N 2 -sturted.1 M N 2 SO M H 2 SO 4 electrolyte (lnk electrolyte) for plcement time of 2 h. Asornce Wvelength(nm) Fig. S13 UV-Vis spectr of N 2 -sturted.1 M N 2 SO M H 2 SO 4 electrolyte under the open-circuit condition using the CC-45 for plcement time of 2 h.

14 Asornce Wvelength(nm) Fig. S14 UV-Vis spectr of Ar-sturted.1 M N 2 SO M H 2 SO 4 electrolyte t -.3 V (vs. RHE) using the CC-45 for rection time of 2 h. 1 8 CC-45 CC -Z''( ohm( Z'( ohm( Fig. S15 The electrochemicl impednce spectroscopy (EIS) nlysis of pristine CC nd CC-45 t -.3 V (vs. RHE) in N 2 -sturted.1 M N 2 SO M H 2 SO 4 electrolyte.

15 NH 3 Yield( 1-1 mol cm -2 s -1 ( 3.5 Pristine CC CC-35 Frdic Efficiency -.3 V -.5 V E (V vs. RHE( CC-25 CC V Frdic Efficiency (%) Fig. S16 The NH 3 yield nd Frdic efficiency of pristine CC, CC-25, CC-35 nd CC-45 t -.3, -.5 nd.7 V (vs. RHE) in N 2 -sturted.1 M N 2 SO M H 2 SO 4 electrolyte for 1 h of rection.