High efficiency conversion of CO2 to methanol using photoelectrocatalyst

PowerPoint Presentation High efficiency conversion of CO2 to methanol using photoelectrocatalyst Reporter Tran Thanh Phuc Class CHHO7B Lecturer Luu Cam Loc Report date March 23, 2019 Outline Introduction Methanol yield Conclusion 2 Nội dung báo cáo gồm 4 phần Giới thiệu Vật liệu và phương pháp Kết quả và thảo luận Kết luận 2 High temperature and high pressure 300°C and 500 bar Using catalyst Introduction Carbon dioxide (CO2) được giải phóng bằng cách đốt các nhiên liệu hóa thạch là nguyên nhân c.

High-efficiency conversion of CO2 to methanol using photoelectrocatalyst • • • • Reporter : Tran Thanh Phuc Class : CHHO7B Lecturer : Luu Cam Loc Report date : March 23, 2019 Outline • Introduction • Methanol yield • Conclusion Introduction High temperature and high pressure 300°C and 500 bar Using catalyst Introduction Introduction Introduction Photocatalytic PC The presence of light Activating a catalyst by ultraviolet (UV) or visible light Semiconductor materials, which can form electrons and holes when exposed to light The reactions are normally either oxidation or reduction Introduction Photocatalytic PC An ideal photocatalyst should have the following properties Introduction Introduction Photocatalytic PC Under ambient temperature and pressure driven by solar energy The PC conversion efficiency of CO2 to methanol (CH3OH) is generally low Under ambient temperature and pressure Electrocatalytic EC Low energetic efficiency, and poor selectivity Introduction Matches the energy band for PC reduction Matches the small overpotential for EC reduction Photoelectrocatalytic (PEC) Cu2O/Fe2O3 NTs Introduction Fe2O3 (iron oxide) Structure and properties Transition metal oxide wüstite (FeO) hematite (Fe2O3) maghemite (-Fe2O3) magnetite (Fe3O4) n-type semiconductor Narrow band gap (2.0–2.2 eV) Absorbs light up to 600 nm The stability in most aqueous solutions (pH > 3) The cheapest semiconductor Introduction Fe2O3 (iron oxide) -Fe2O3 nanotubes (NTs) large surface areas could reduce the electron–hole pairs recombination Conduction band: 0.28 eV nanotubes have higher PC activity Valence band: 2.48 eV The reduction of Fe2O3 is very weak for the positive conduction band Cuprous oxide (Cu2O) was selected to couple with Fe2O3 NTs Introduction The p-type semiconductors Cuprous oxide (Cu2O) Low toxicity, low cost, earth abundant properties The CB of Cu2O is more negative than the CO2 reduction potential and the band gap is relatively narrow (1.9–2.2 eV) Conduction band: -1.3 eV Serious photocorrosion of Cu2O in aqueous solution Photocorrosion Photocorrosion of of the the photocathode photocathode will will greatly greatly decline decline the the overall overall reduction reduction efficiency efficiency since since most most photogenerated photogenerated holes holes are are consumed consumed by by Cu Cu22O O itself itself Introduction Cu2O/Fe2O3 NTs The material with double-layer Cu2O spheres (Cu2O/Fe2O3 NTs-30) showed excellent PEC properties with a suitable energy band gap (1.96 eV) and the smallest over-potential (180 mV) Valence band: 1.09 eV Conduction band: -0.87 eV Introduction Cu2O/Fe2O3 NTs A CO2 in V Gas out to GC Light (Xenon lamp) Cu2O/Fe2O3 NTs-30 ref Counter electrode Methanol yield 4.94 2.29 1.39 0.90 Methanol yield of the PEC,PC, and EC reduction of CO2 on Cu2O/Fe2O3 NTs-30 Compared to EC or PC, the Cu2O/Fe2O3 NTs showed superior PEC reduction performance for the efficient conversion of CO2 to CH3OH Mechanism CB VB Cu2O/Fe2O3 NTs + h  Cu2O/Fe2O3 NTs (h+ + e-) H2O +2h+  0.5O2 +2H+ +2eCO2 + 6H+ +6e-  CH3OH + H2O Comparison Conclusion The material with double-layer Cu2O spheres (Cu2O/Fe2O3 NTs-30) showed excellent PEC properties with a suitable energy band gap (1.96 eV) and the smallest overpotential (180 mV) Cu2O/Fe2O3 NTs-30 showed two types of synergism in the PEC reduction of CO2: (i) between electrocatalysis and photocatalysis and (ii) between Cu2O and Fe2O3-NTs The faradaic efficiency and methanol yield reached 93% and 4.94 mmol L-1 cm-2 after h, respectively The excellent performance of Cu2O/Fe2O3 NTs-30 for the PEC reduction of CO2 was well confirmed Still used external voltage ... (1.9–2.2 eV) Conduction band: -1.3 eV Serious photocorrosion of Cu2O in aqueous solution Photocorrosion Photocorrosion of of the the photocathode photocathode will will greatly greatly decline decline... properties Introduction Introduction Photocatalytic PC Under ambient temperature and pressure driven by solar energy The PC conversion efficiency of CO2 to methanol (CH3OH) is generally low Under... Cu2O/Fe2O3 NTs A CO2 in V Gas out to GC Light (Xenon lamp) Cu2O/Fe2O3 NTs-30 ref Counter electrode Methanol yield 4.94 2.29 1.39 0.90 Methanol yield of the PEC,PC, and EC reduction of CO2 on Cu2O/Fe2O3