Name: Idris Ibnu Malik City, date of birth: Surabaya, December 3rd - PowerPoint PPT Presentation

Name: Idris Ibnu Malik City, date of birth: Surabaya, December 3rd 1990 Hometown: Surabaya, Indonesia Education: Unergraduate ( (2009 2009-2013) 13) - Chemistry Department, Institut Teknologi Sepuluh Nopember Surabaya, Indonesia Master ( (201 013-now) - Chemistry Department, Institut Teknologi Sepuluh Nopember Surabaya, Indonesia - Chemical Engineering Department, NTUST Taipei, Taiwan

Oral Defense High Surface Area Ti 4 O 7 Supported Platinum Catalyst for Oxygen Reduction Reaction Idris ris I Ibnu M Malik lik M10306803 Sup Supervisor : : Prof of. B Bing ng-Joe oe H Hwang ng NanoElectr oElectrochemistry, D ochemistry, Department o tment of Chemica ical E l Engineering, T ineering, Taiwan T an Tech Oral Defense

Outline Introduction 1. Review of Previous Approach 2. Motivation and Approach 3. Result and Discussion 4. Conclusion 5. Outlook 6. 2015/8/1 3

Introduction 2015/8/1 4

Energy Issue Fossil fuels currently supply most of the world’s energy needs Energy flow diagram for the United States Fig. 1.1 P. 1 NATURE | VOL 414 | 15 NOVEMBER 2001 2015/8/1 5

Hydrogen Energy Challenges in realizing hydrogen fuel cell Fig. 1.2 P. 2 NATURE| VOL 464|29 APRIL 2010 2015/8/1 6

Fuel Cell System A: 2H 2 → 4H + + 4e - C: O 2 + 4H + + 4e - → 2H 2 O Total: 2H 2 + O 2 → 2H 2 O CO 2 free electricity 2015/8/1 7 www.hyundailikesunday.com/2014/08/11/how-a-fuel-cell-vehicle-works/

Fuel Cell Catalyst Issues In the catalyst point of view, there are two main issues toward wide commercialization of PEFCs. The catalyst component: 1. Active metal (Pt) Cost - Pt is expensive, solution:  reducing Pt particle size  alloying Pt with other metals  utilizing non noble metals 2. Support material Fig. 2.2 P. 8 Performance - durability of electrocatalyst, solution:  utilizing non carbon support 2015/8/1 8

Carbon Corrosion Carbon corrosion causes: Catalyst coalescence 1. Detachment of catalyst 2. particles from the carbon support material Fig. 1.4 P. 4 C + 2H 2 O → CO 2 + 4H + + 4e - E 0 = 0.207 V vs. RHE at 25 ° C 2015/8/1 9

Support Material Requirement to prevent catalyst High degradation stability Good support material High High to drive the to disperse metal surface conductivity electrons to the catalyst area current collectors 2015/8/1 10

Ti 4 O 7 Ti 4 O 7 is substoichiometric titanium oxide. It has general formula Ti n O 2n−1 (4<n<10), which is known as Magnéli phase. Ti 4 O 7 is promising catalyst support material because: 1. High electronic conductivity 2. Stability but, the surface area is low. 2015/8/1 11

Review of Previous Approach 2015/8/1 12

Challenges in Ti 4 O 7 Synthesis General route to synthesize Ti 4 O 7 : Ti(IV) → reduced in high temperature → Ti 3.5+ High temperature synthesis So, how to ↓ synthesize high Uncontrollable particle growth surface area ↓ Ti 4 O 7 ? Low surface area 2015/8/1 13

Recent Development of Ti 4 O 7 Synthesis Reduction of TiO 2 in high temperature and H 2 atmosphere 1. 1050 ° C (6 h) Surface area: 0.95 m 2 g -1 TiO 2 Ti 4 O 7 H 2 gas Electrochemistry Communications 7 (2005) 183–188 1050 ° C Surface area: 2 m 2 g -1 TiO 2 Ti 4 O 7 H 2 gas Journal of The Electrochemical Society, 155 (4) B321-B326 (2008) 950 ° C (4 h) TiO 2 Ti 4 O 7 Surface area: 2.7 m 2 g -1 H 2 gas Electrochimica Acta 55 (2010) 5891–5898 Advantage: carbon free, simple synthesis pathway Disadvantage: low surface area 2015/8/1 14

Recent Development of Ti 4 O 7 Synthesis Modified reduction of TiO 2 in high temperature and 2. H 2 atmosphere electrospinning 1050 ° C (6h) Ti(IV) Ti 4 O 7 TiO 2 nanofiber isopropoxide H 2 gas Surface area: 6 m 2 g -1 Electrochimica Acta 59 (2012) 538–547 1050 ° C (4h) H 2 gas Surface area: 26 m 2 g -1 J. Mater. Chem., 2012, 22, 16560–16565 Advantage: higher surface area, carbon free Disadvantage: multiple synthesis pathway 2015/8/1 15

Recent Development of Ti 4 O 7 Synthesis Reduction of Ti(IV) precursor in high temperature and inert 3. atmosphere 800–1,100 ° C (2 h) Ti 4 O 7 TiO 2 + carbon black vacuum Surface area: ~4 m 2 g -1 Carbon content: n.a. J Mater Sci: Mater Electron (2013) 24:4853–4856 Ti(IV) ethoxide 950 ° C Ti 4 O 7 Ti composite + Ar gas PEG 400 Surface area: 290 m 2 g -1 Nature Communications (2014) 5:4759 Carbon content: 15 wt% Ti(IV) ethoxide 860 ° C (3-4 h) Ti 4 O 7 Ti composite + Ar gas ethyleneimine Surface area: 180 m 2 g -1 Energy Environ. Sci., 2015,8, 1292-1298 Carbon content: <2 wt% Advantage: high surface area, safer Disadvantage: contains carbon 2015/8/1 16

Summary of Ti 4 O 7 Synthesis Calcination condition Surface Reducing Carbon Year Ti(IV) precursor area Temp Time agent content Gas (m 2 g -1 ) ( ° C) (hrs) 2005 TiO 2 1050 6 H 2 H 2 0.95 0 2008 TiO 2 1050 n.a. H 2 H 2 2 0 2010 TiO 2 950 4 H 2 H 2 2.75 0 titanium(IV) 2012 1050 6 H 2 H 2 6 n.a. isopropoxide 2012 TiO 2 1050 4 H 2 H 2 26 0 800 - carbon 2013 TiO 2 2 vacuum ~4 n.a. 1100 black titanium(IV) 2014 950 n.a. Ar PEG 400 290 15 wt% ethoxide titanium(IV) ethylene- 2015 860 3-4 Ar 180 <2 wt% ethoxide imine Table 2.2 P. 24 2015/8/1 17

Roadmap of Ti 4 O 7 Synthesis 2015/8/1 18

Motivation and Approach 2015/8/1 19

Motivation In this work, we want to synthesize high surface area Ti 4 O 7 to support platinum catalyst for oxygen reduction reaction. Therefore, the three requirement of good catalyst support can be achieved. 1. High surface area 2. Good electronic conductivity 3. Good stability 2015/8/1 20

Approach Ti 4 O 7 Synthesis EtOH Ar white powder Ti 4 O 7 Titanium(IV) ethoxide + stir at 60-80 ° C calcination at 950 ° C for 12 hours for 4 hours followed by Poly(ethylene glycol) 400 drying at 100 ° C for 6 hours Pt Deposition ethylene glycol + Ti 4 O 7 20% Pt/Ti 4 O 7 stir at 160 ° C for 1 hours in microwave 2015/8/1 21

Experimental Framework 2015/8/1 22

Flowchart of Ti 4 O 7 Synthesis + Fig. 3.1 P. 27 2015/8/1 23

Flowchart of Platinum Deposition Fig. 3.2 P. 28 2015/8/1 24

Flowchart of Carbon Removal Extraction treatment Fig. 3.3 P. 29 2015/8/1 25

Flowchart of Carbon Removal Solvent treatment Fig. 3.4 P. 30 2015/8/1 26

Flowchart of Carbon Removal Acid treatment Fig. 3.5 P. 31 2015/8/1 27

Flowchart of Carbon Removal Base treatment Fig. 3.6 P. 31 2015/8/1 28

Result and Discussion Ti 4 O 7 Support Material 2015/8/1 29

XRD Ti10PEG03 Ti10PEG04 Ti10PEG05 Ti 4 O 7 (PDF 50-0787) anatase-TiO2 (PDF 84-1286) rutile-TiO2 (PDF 84-1284) Fig. 4.1 P. 38 2015/8/1 30

TGA and Conductivity The increasing weight is caused by oxidation of Ti 4 O 7 to the more stable TiO 2 phase. Fig. 4.2 P. 40 Sample Decomposition (%) Sample Conductivity (S cm -1 ) Ti10PEG03 7.57 Ti10PEG03 95.47 Ti10PEG04 9.44 Ti10PEG04 172.96 Ti10PEG05 8.82 Ti10PEG05 113.43 Table 4.1 P. 41 Table 4.3 P. 45 2015/8/1 31

Physisorption Analysis Type IV mesopore (2-50 nm) Fig. 4.3 P. 42 Fig. 4.4 P. 43 BET surface area (m 2 g -1 ) Sample Ti10PEG03 154.9 Ti10PEG04 187.6 Ti10PEG05 178.3 Table 4.2 P. 44 2015/8/1 32

SEM Images Ti10PEG03 The sample morphology seems to be built from many granules. It indicates the PEG was successfully inhibit the formation of large particle during heat treatment. Ti10PEG04 Ti10PEG05 Fig. 4.5 P. 44 2015/8/1 33

Cyclic Voltammetry No oxidation peaks are observed indicates the stability of Ti 4 O 7 support materials. Fig. 4.6 P. 46 2015/8/1 34

Summary Based on XRD results, the best Ti(IV) ethoxide and PEG 400 1. ratio in Ti 4 O 7 synthesis was 10:4 weight ratio. SEM images clearly show that the entire samples had pore 2. structure. CV analysis results revealed that the entire samples were 3. stable in acidic environment. Carbon residue BET surface area Conductivity Sample (m 2 g -1 ) (%) (S cm -1 ) Ti10PEG03 7.57 154.9 95.47 Ti10PEG04 9.44 187.6 172.96 Ti10PEG05 8.82 178.3 113.43 2015/8/1 35

Result and Discussion Carbon Removal 2015/8/1 36

Carbon Removal by Extraction Treatment 7.33% 6.72% mixture of n-heptane (d = 0.68 g mL -1 ) and 1,2-dichlorobenzene (d = 1.30 g mL -1 ) Fig. 5.1 P. 49 after extraction removed organic phase 2015/8/1 37

Carbon Removal by Solvent Treatment The decreasing decomposition after treatment indicates some carbon have 7.33% been dissolved in the solvent and removed 6.43% from Ti 4 O 7 support material. Fig. 5.2 P. 50 collected solvent after mixture of Ti 4 O 7 and centrifugation 1,2-dichlorobenzene 2015/8/1 38

Carbon Removal by Acid-base Treatment The increasing weight after acid treatment 7.33% indicates 6.86% sulfuric acid 7.67% area trapped in the Ti 4 O 7 support material. Fig. 5.3 P. 51 collected acid-base mixture of Ti 4 O 7 and after centrifugation 2M H 2 SO 4 2015/8/1 39