ISO/TS 23362:2021

Nanotechnologies - Nanostructured porous alumina as catalyst support for vehicle exhaust emission control - Specification of characteristics and measurement methods

This document specifies characteristics to be measured of nanostructured porous alumina in powder form as catalyst support for vehicle exhaust emission control and their relevant measurement methods. It includes critical characteristics that are required to be measured and additional characteristics that are recommended to be measured, based upon agreement between the interested parties. Measurement methods for each characteristic are recommended. This document is applicable to nanostructured porous alumina for gasoline-powered cars. It does not apply to characteristics specific for health, the environment and safety issues.

Nanotechnologies — Alumine poreuse nanostructurée utilisée comme support catalytique pour le contrôle des émissions d'échappement des véhicules — Spécification des caractéristiques et mesure

General Information

• Status: Published
• Publication Date: 07-Jan-2021
• ICS: 07.120 - Nanotechnologies
• ICS: 43.060.20 - Pressure charging and air/exhaust gas ducting systems
• Technical Committee: ISO/TC 229 - Nanotechnologies
• Drafting Committee: ISO/TC 229/WG 4 - Material specifications
• Current Stage: 9093 - International Standard confirmed
• Start Date: 22-Jul-2024
• Completion Date: 13-Dec-2025

Overview

ISO/TS 23362:2021 - Nanotechnologies - nanostructured porous alumina as catalyst support for vehicle exhaust emission control - specifies the characteristics to be measured for nanostructured porous alumina powder used as catalyst support in gasoline-powered cars and recommends measurement methods. It defines critical characteristics (required measurements) and additional characteristics (recommended by agreement), gives measurement method guidance, and explains reporting needs. The document is focused on material performance and does not cover health, environmental or safety-specific properties.

Key topics and requirements

• Critical characteristics that must be measured and reported:
  • Specific surface area (SSA) - measured by gas adsorption (BET); SSA must be reported before and after thermal treatment.
  • Specific pore volume - measured by gas adsorption (BJH), reported before and after thermal treatment.
  • Pore diameter - calculated from gas adsorption data (BJH).
  • Impurity content - measured by ICP-OES / ICP-AES.
• Additional characteristics (recommended):
  • Apparent density (funnel method)
  • Tap density (cylinder tapping method)
  • Particle size (laser diffraction)
  • Loss on ignition (incineration and gravimetry)
• Measurement conditions and treatment:
  • Samples are sensitive to moisture; storage in a dry environment is recommended for comparability.
  • Typical sample preparation: drying (recommended 200–300 °C) prior to SSA measurement.
  • Recommended thermal treatment for stability testing: 1 000–1 100 °C for 4–10 h (parameters can be agreed between buyer and seller).
• Reporting: Measured values of critical characteristics shall be provided to buyers during purchase; templates and reporting guidance are included.

Practical applications

• Ensures consistent quality control and traceability of nanostructured porous alumina used as catalyst support in three-way catalytic converters (TWCs) for gasoline vehicles.
• Helps suppliers and purchasers define acceptance criteria for:
  • Noble metal dispersion and loading (influenced by SSA and pore volume)
  • Thermal stability and service life of catalytic converters
  • Minimizing catalyst deactivation from impurities
• Useful for: material manufacturers, catalyst formulators, automotive OEMs, testing and certification laboratories, and procurement/specification teams.

Who should use this standard

• Manufacturers and sellers of porous alumina powders
• Buyers and procurement specialists specifying catalyst supports
• Quality assurance and R&D teams developing TWC materials
• Test laboratories performing material characterization according to standardized methods

Related standards

Key referenced methods include:

• ISO 18757:2003 (SSA / BET)
• ISO 15901-2:2006 (porosity, BJH)
• ISO 17942:2014 (pore diameter procedures)
• ISO 10058-3:2008 (ICP-based impurity analysis)
• ISO 3923-1:2018, ISO 3953:2011, ISO 13320:2020, ISO 11536:2015 (additional properties)

Keywords: ISO/TS 23362:2021, nanostructured porous alumina, catalyst support, vehicle exhaust emission control, specific surface area, pore volume, pore diameter, BET, BJH, ICP-OES, three-way catalytic converter.

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 23362
First edition
2021-01
Nanotechnologies — Nanostructured
porous alumina as catalyst support
for vehicle exhaust emission control
— Specification of characteristics and
measurement methods
Reference number
©
ISO 2021
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 2
4 Characteristics and their measurement methods . 3
4.1 General . 3
4.2 Critical characteristics and their measurement methods . 3
4.3 Additional characteristics and their measurement methods . 3
5 Descriptions of characteristics and measurement methods . 3
5.1 General . 3
5.2 Specific surface area . 4
5.3 Specific pore volume . 4
5.4 Pore diameter . 4
5.5 Impurity content . 4
5.6 Apparent density . 5
5.7 Tap density . 5
5.8 Particle size . 5
5.9 Loss on ignition . 6
6 Reporting . 6
Annex A (informative) Schematic illustration of three-way catalytic converter .7
Annex B (informative) Example of reporting table format . 8
Bibliography . 9
Foreword
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
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iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 229, Nanotechnologies.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

Introduction
Nanostructured porous alumina as catalyst support for vehicle exhaust emission control plays an
[15]
important role in automotive exhaust treatment . Three-way catalytic converters (TWCs) have
been used in vehicle exhaust control systems worldwide, which can convert carbon monoxide (CO),
hydrocarbon (HC) and oxynitride (NOx) into carbon dioxide (CO ), nitrogen (N ) and oxygen (O ).
2 2 2
Nanostructured porous alumina has the advantages of a high specific surface area (SSA) and excellent
thermal stability, which makes TWCs keep high catalytic activity at a temperature of 900 °C to 1 000 °C
[16]
in gasoline cars. As one of the most important materials in the catalytic converter , nanostructured
porous alumina with proper performance is in great demand. In the automotive exhaust treatment
field, almost 11,000 tons of porous alumina powders are needed per year.
SSA, specific pore volume, impurities and thermal stability are the main characteristics affecting
[17]
the performance of nanostructured porous alumina as catalyst support . A high SSA can facilitate
homogeneous dispersion of noble metal. A suitable specific pore volume ensures efficient noble metal
loading and allows reaction gas to pass through and contact with the catalyst. Impurities can deactivate
the noble metal catalyst and thus are harmful. An excellent thermal stability guarantees that TWCs
maintain at high activity levels after a long distance running and thus have a prolonged service life. The
schematic illustration is shown in Annex A.
The world market demand for nanostructured porous alumina is growing year by year. Currently,
however, there are no standards for manufacturers in managing quality control and assurance, and for
users in selecting suitable materials for TWCs.
This document provides characteristics and measurements of nanostructured porous alumina as
catalyst support for vehicle exhaust emission control. It aims to facilitate worldwide transactions
between buyers and sellers of nanostructured porous alumina.
TECHNICAL SPECIFICATION ISO/TS 23362:2021(E)
Nanotechnologies — Nanostructured porous alumina as
catalyst support for vehicle exhaust emission control —
Specification of characteristics and measurement methods
1 Scope
This document specifies characteristics to be measured of nanostructured porous alumina in powder
form as catalyst support for vehicle exhaust emission control and their relevant measurement methods.
It includes critical characteristics that are required to be measured and additional characteristics that
are recommended to be measured, based upon agreement between the interested parties. Measurement
methods for each characteristic are recommended.
This document is applicable to nanostructured porous alumina for gasoline-powered cars. It does not
apply to characteristics specific for health, the environment and safety issues.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/TS 80004-1, Nanotechnologies — Vocabulary — Part 1: Core terms
ISO/TS 80004-6, Nanotechnologies — Vocabulary — Part 6: Nano-object characterization
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/TS 80004-1, ISO/TS 80004-6
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1.1
specific surface area
SSA
absolute surface area of the sample divided by sample mass
[SOURCE: ISO 9277:2010, 3.11]
3.1.2
specific pore volume
volume of open pores per unit mass of a material
3.1.3
pore diameter
diameter of a pore in a model in which the pores typically are assumed to be cylindrical in shape and
which is calculated from data obtained by a specified procedure
[SOURCE: ISO 15901-1:2016, 3.15]
3.1.4
apparent density
loose bulk density
dry mass per unit volume of a powder obtained by free pouring under specified conditions
[SOURCE: ISO 9161:2019, 3.1]
3.1.5
tap density
dry mass per unit volume of a powder in a container that has been tapped under specified conditions
[SOURCE: ISO 9161:2019, 3.2]
3.1.6
impurity
metallic or non-metallic element present in a material, but not intentionally added to the material
[SOURCE: ISO 3522:2007, 3.10, modified — “in a material, but not intentionally added to the material” has
replaced “but not intentionally added to a metal, and the minimum content of which is not controlled”.]
3.1.7
loss on ignition
change in mass of a material held at a specified temperature, excluding the loss due to hygroscopic
moisture
[SOURCE: ISO 11323:2010, 8.4, modified — “a material held at a specified temperature” has replaced
“an ore held at 1 000 °C”.]
3.1.8
ceramic honeycomb
fine ceramic body having multiple channels typically arranged in a honeycomb structure
[SOURCE: ISO 20507:2014, 2.1.18, modified — Note 1 to entry has been deleted.]
3.2 Abbreviated terms
BET Brunauer–Emmett–Teller
BJH Barrett–Joyner–Halenda
ICP-AES inductively coupled plasma atomic emission spectrometry
ICP-OES inductively coupled plasma optical emission spectrometry
SSA specific surface area
TWC three-way catalytic converters
XRF X-ray fluorescence spectrometry
2 © ISO 2021 – All rights reserved

4 Characteristics and their measurement methods
4.1 General
Critical and additional characteristics to be measured of nanostructured porous alumina are listed in
Tables 1 and 2, respectively.
Although the International Standards given in Tables 1 and 2 are individually applicable to general or
specific materials, all the documents are not yet fully validated whether they are specifically applicable
to nanostructured porous alumina. Their application shall be validated and decided by the standards
users themselves.
As the nanostructured porous alumina is liable to adsorb moisture, its characteristics can be affected
by the storage conditions. The sample for measurements should be stored in a dry environment. If not,
the buyers and the sellers should agree upon the storage conditions of the samples for comparability of
results.
4.2 Critical characteristics and their measurement methods
The critical characteristics listed in Table 1 shall be measured. The measured values of these
characteristics shall be provided to the buyers during purchase. The SSA and the specific pore volume
shall be measured before and after thermal treatment.
The measurement methods listed in Table 1 should be used.
Table 1 — Critical characteristics and their measurement methods
Characteristics Units Measurement methods Relevant standard(s)
Specific surface area m /g Gas adsorption method ISO 18757:2003
Specific pore volume m /kg Gas adsorption method ISO 15901-2:2006
Pore diameter nm Gas adsorption method ISO 1590
...