# Milling-Induced Defects in Ni/Zirconia Catalysts for Enhancing Catalytic Activity in Dry Methane Reforming

## TL;DR

Milling zirconia creates defects that improve the performance of Ni/ZrO2 catalysts in dry methane reforming for syngas production.

## Contribution

Mild milling of zirconia introduces stable oxygen vacancies and enhances catalytic activity in dry methane reforming.

## Key findings

- Mild milling at 400 rpm produced the most active Ni/ZrO2 catalyst for dry methane reforming.
- The catalyst achieved 29% CH4 and 39% CO2 conversion at 600 °C.
- Activity is influenced by phase changes in zirconia and oxygen vacancy characteristics.

## Abstract

Alteration of the support structure via milling is a
feasible yet
rarely applied strategy for boosting the performance of the catalyst
in dry methane reforming for syngas production. In this study, we
introduce stable oxygen vacancies in the zirconia structure, which
enhance the activation of the feedstock, specifically CO2, while preserving the specific surface area and porosity of the
material under reaction conditions. The activity of the tested Ni/ZrO2 assemblies shows a clear dependence on the milling intensity
of ZrO2, with mild milling at 400 rpm yielding the most
active catalyst. At 600 °C, this material achieved the highest
feedstock conversion among the tested samples, with 29% for CH4 and 39% for CO2. Spectroscopic characterization
indicates that the activity of the tested catalysts is controlled
by a partial change in the phase composition of the support from monoclinic
to tetragonal under reaction conditions, as well as the nature and
population of O2
– species, oxygen vacancies,
Zr3+ defects, and Ni–ZrO2 interfacial
interactions.