# Additively Manufactured Geopolymer Monoliths as Robust Supports for High Temperature Catalytic Reactions

## TL;DR

3D-printed geopolymer structures are shown to be durable and effective supports for high-temperature catalytic reactions like methane steam reforming.

## Contribution

This work demonstrates the use of 3D-printed geopolymers as thermally stable catalyst supports through material extrusion and Ni impregnation.

## Key findings

- 3D-printed geopolymer monoliths retained mechanical integrity after calcination at 800 °C.
- Ni-geopolymer catalysts showed stable performance in methane steam reforming at high temperatures.
- Alkali-rich geopolymer matrix stabilized nickel aluminosilicate phases, enhancing metal-support interactions.

## Abstract

Additively manufactured
geopolymers are emerging as a versatile
class of structured materials combining thermal and mechanical resilience
for application in extreme environments. In this work, porous geopolymer
monoliths were fabricated by material extrusion (MEX) using tailored
metakaolin-based pastes, and printability was quantitatively assessed
through a rheological protocol that links precursor attributes to
processing behavior. The resulting 3D-printed structures (70% porosity,
30 m2/g) retained mechanical integrity after calcination
at 800 °C, in contrast to conventionally cast counterparts that
suffered severe strength loss. Upon Ni impregnation, temperature-programmed
reduction (TPR-H2) evidenced strong metal–support
interactions and the formation of stable nickel aluminosilicate phases,
highlighting the role of the alkali rich geopolymer matrix in interfacial
stabilization. As a proof of concept, methane steam reforming (MSR)
was used to validate functionality under high temperature conditions
(800-900 °C). Ni-geopolymer catalysts exhibited stable performance
without deactivation over 2 h. These results position 3D-printed geopolymers
as thermally stable, interface-engineered supports for high temperature
catalytic technologies beyond the specific MSR case study.