NAPP Near Ambient Pressure Photoemission at ALBA Carlos Escudero - - PowerPoint PPT Presentation

▶
napp
SMART_READER_LITE
LIVE PREVIEW

NAPP Near Ambient Pressure Photoemission at ALBA Carlos Escudero - - PowerPoint PPT Presentation

Sep 06, 2022 43 likes •276 views

1 NAPP Near Ambient Pressure Photoemission at ALBA Carlos Escudero BL24 CIRCE BEAMLINE QUANTY, CRISPY AND CTM4XAS WORKSHOP ALBA Synchrotron Light Source June 4 th - 6 th , 2018 cescudero@cells.es NAPP, Near Ambient Pressure

slide-1
SLIDE 1

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

1

NAPP

Near Ambient Pressure Photoemission at ALBA

QUANTY, CRISPY AND CTM4XAS WORKSHOP

ALBA Synchrotron Light Source June 4th - 6th, 2018 cescudero@cells.es

Carlos Escudero BL24 – CIRCE BEAMLINE

slide-2
SLIDE 2

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

2

Outline

  • BL24- CIRCE: Near Ambient Pressure Photoemission (NAPP)
  • NAPP at ALBA synchrotron, description and capabilities
  • NAPP, scientific applications
  • Water adsorption
  • In situ studies of Electrochemical Promotion Of Catalysts
  • Surface rearrangement of bimetallic NPs in real catalysts
  • Soot oxidation studies with CeO2
slide-3
SLIDE 3

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

3

CIRCE - BL24 @ ALBA

NAPP PEEM

  • Source: APPLE II undulator with variable polarization
  • Plane Grating Monochromator with photon energy range from 100 to 2000 eV
  • Beam size at sample 100 μm (H) x 20 (V) μm for NAPP
  • ΔE/E= 8500 @ 400 eV
  • Flux: 10-11 – 10-12photons/s (130 mA)

PEEM: PhotoEmission Electron Microscopy NAPP: Near Ambient Pressure Photoemission

slide-4
SLIDE 4

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

NAPP, main capabilities

  • Possibility of fully horizontal sample transfer
  • UHV suitcase for sample transfer under vacuum

Gases: O2, CO, CO2, H2, Hydrocarbons, N2, He Vapors: H2O, MeOH, EtOH

  • XPS measurements under gas mixtures

up to ≈ 20 mbar, with and without flow control Gas monitoring by RGA spectrometer

  • Peltier manipulator for sample cooling

down to – 22.3°C (UHV) in 10 min down to – 13°C (1 mbar H2Ov) in 10 min

  • Sample heating by resistive heater or IR laser

With button resistive heater up to 900°C in UHV) and 700°C (20 mbar N2) With IR laser heater up to 1200°C in UHV) and 900°C (20 mbar N2)

differential pumping system, 109 P drop

  • PBE, photon beam entrance system

Adjustable apertures

4

slide-5
SLIDE 5

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

Heterogeneous Catalysis Environmental Science Energy generation

NAPP: scientific applications

5

slide-6
SLIDE 6

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

Water Condensation Mechanisms on Superhydrophobic and Superhydrophilic Titanium Dioxide Nanotubes

6

  • M. Macias-Montero et al., Langmuir 33, p.6449 (2017)
slide-7
SLIDE 7

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

In situ monitoring of the phenomenon of Electrochemical Promotion Of Catalysis

J.P.Espinós et. al., Journal of Catalysis 358 (2018) 27–34

7

slide-8
SLIDE 8

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

J.P.Espinós et. al., Journal of Catalysis 358 (2018) 27–34

8

slide-9
SLIDE 9

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

Influence of the support on surface rearrangements of bimetallic nanoparticles in real catalysts

  • N. J. Divins and Jordi Llorca (UPC)
  • I. Angurell (UB)
  • V. Pérez-Dieste , C. Escudero (ALBA)

9

  • N. J. Divins et al., Science 346, p.620 (2014)
slide-10
SLIDE 10

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

NPs: structure and composition during reaction ESR – Ethanol Steam Reforming C2H5OH + 3 H2O 6 H2 + 2 CO2 H2

CO2 neutral

catalyst O2 Biomass Bioethanol CO2 H2O Fuel cell

ΔHR=347 kJ/mol

Which catalyst?

Bioethanol

10

slide-11
SLIDE 11

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

11

Rh0.5Pd0.5 Nanoparticles (NPs) for Ethanol Steam Reforming (ESR)

  • Rh breaks C-C bond and

sp3 C-H bond

  • Pd efficiently

recombines H-H

  • CeO2 redox properties

and oxygen storage capacity

Why Rh0.5Pd0.5 NPs?

Mean nanoparticle diameter = 4 ± 1 nm Rh and Pd are alloyed Atomic ration Rh/Pd=1

EDX STEM

HRTEM characterization

  • N. J. Divins et al., Science 346, p.620 (2014)
slide-12
SLIDE 12

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

12

Rhodium

Mean Free Path ( Å) 16 10 7

Rh-rich Shell

Atomic Fraction

200 400 600 800 100012001400 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Kinetic Energy (eV)

Rhodium Palladium

Mean Free Path ( Å) 16 10 7

Rh-rich Shell

Atomic Fraction

200 400 600 800 100012001400 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Kinetic Energy (eV)

Rhodium Palladium 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Atomic Fraction

Rh0.5Pd0.5

1.0 NO NO+CO NO NO+CO O2 Reaction:

T = 300o C

SHELL

From previous experiments…

Rh0.5Pd0.5 NPs

  • F. Tao et al, Science. 322, 932 (2008)

How does CeO2 influence the surface rearrangement of NPs in real catalysts? RhPd

CeO2

RhPd

H2 300°C reaction 550°C H2 550°C

0.05 mbar

hν=670 eV Outer shell hν=875 eV Intermediate layers hν=1150 eV Core

slide-13
SLIDE 13

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

CH4 + H2O 3 H2 + CO

Catalytic Performance Evaluation

H2 production by Rh0.5Pd0.5/CeO2 is twice than by model Rh0.5Pd0.5 NPs

(open black circles) Less CO, less CH4

C2H5OH H2 + CO + CH4 CO + H2O H2 + CO2

ESR reaction steps with noble metals:

13

  • N. J. Divins et al., Science 346, p.620 (2014)
slide-14
SLIDE 14

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

Pd 3d Rh 3d O 1s

670 eV 875 eV 1150 eV

  • x

red

  • x

red

670 eV 875 eV 1150 eV

RhPd RhPd

CeO2 O-Ce O-M O-H

ESR conditions, 823K

14

slide-15
SLIDE 15

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

15

H2 550ºC ESR reaction 550ºC

red red

  • x
  • x

H2 300ºC Rh Pd

  • x
  • x

red red

Rh Pd

  • x
  • x

red red

RhPd/CeO2 RhPd

  • N. J. Divins et al., Science 346, p.620 (2014)
slide-16
SLIDE 16

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

16

Model NPs vs real catalyst

  • N. J. Divins et al., Science 346, p.620 (2014)
slide-17
SLIDE 17

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

Carbon soot oxidation with ceria based catalysts

  • L. Soler, A. Casanovas and Jordi Llorca (UPC)
  • E. Aneggi, A. Trovarelli (UniUD)
  • V. Pérez-Dieste , C. Escudero (ALBA)

17

  • L. Soler et al., ChemCatChem 8, p.2748 (2016)
slide-18
SLIDE 18

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

18

Soot, a serious environmental and health concern

Soot combustion requires T > 600 °C, therefore catalysts are required to lower this T

  • Capacity to store and release oxygen
  • Redox properties of the Ce3+/4+ couple
  • Structural integrity
  • A. Bueno López, Appl. Cat. B: Environmental 146, p.1 (2014)

CeO2 based catalysts are among the most effective

*CeO2 based catalysts are used in Three-Way Catalytic converters (TWC) for cars pollution control since mid 1980´s *

slide-19
SLIDE 19

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

19

Reaction mechanism

  • Soot oxidation proceeds through a Mars-Van Krevelen mechanism
  • A. Bueno López et al., J Catal. 230, p.237 (2005)
  • B. K. Harada et.al., J. Phys. Chem. C 118, p559 (2014)
  • The mechanism is also associated

with the availability of adsorbed active

  • xygen species that spill over onto the soot surface
  • A. Bueno López et al., J Catal. 230, p.237 (2005)
  • G. Mul et.al., J. Catal. 179, p258 (1998)
  • G. Preda et. al., J. Phys. Chem. C 115, p.5817 (2011)
  • J. Kullgren et. al., J. Phys. Chem. Lett. 4, p.604 (2013)
  • Formation of O2

‒ and O2 2‒ are suggested as precursor surface species

responsible for soot oxidation

  • J. Xuet. al., Chem. Commun. 46, p.1887 (2010)
  • J. Soria et. al., J. Chem. Soc. Trans. 91, p.1669 (1995)
  • V. Pushkarev et.al., J. Phys. Chem. B 108, p.5341 (2004)
  • E. Saab et. al., Carbon 45, p.561 (2007)
slide-20
SLIDE 20

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

20

CeO2-soot

prepared by tight compact mode

Weight ratio catalyst-soot 20:1 Bare CeO2

1 mbar Ar, 450 ˚C

NAPP experiments: CeO2 soot vs bare CeO2

CeO2–soot

1 mbar Ar, 450 ˚C

CeO2–soot

1 mbar Ar, 550 ˚C

CeO2–soot

1 mbar O2, 550 ˚C

C/Ce 24.4 16.0 2.9

  • L. Soler et al., ChemCatChem 8, p.2748 (2016)

Ce 3d

slide-21
SLIDE 21

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

21

Bare CeO2 1 mbar Ar, 450 ˚C CeO2–soot 1 mbar O2, 550 ˚C CeO2–soot 1 mbar O2, 550 ˚C CeO2–soot 1 mbar Ar, 550 ˚C 532.2 eV O2

–

530.5 eV O2

2–

  • L. Soler et al., ChemCatChem 8, p.2748 (2016)

CeO2 soot vs bare CeO2

O 1s

CeO2-soot

prepared by tight compact mode

Weight ratio catalyst-soot 20:1

slide-22
SLIDE 22

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

22

Scheme of the mechanism for soot oxidation

  • ver ceria-based catalysts
  • L. Soler et al., ChemCatChem 8, p.2748 (2016)
slide-23
SLIDE 23

6/06/2018 Carlos Escudero NAPP, Near Ambient Pressure Photoemission at ALBA

Thanks to all ALBA staff

… And thank you for your attention!