# Ni- and Zn-Doping Effects on Cu/SiO2 Catalysts in Nonoxidative Ethanol Dehydrogenation

## TL;DR

This paper studies how adding Ni and Zn to Cu/SiO2 catalysts affects their performance in converting ethanol to acetaldehyde and butadiene at lower temperatures.

## Contribution

The study introduces Ni- and Zn-doped Cu/SiO2 catalysts that improve activity and stability in ethanol dehydrogenation.

## Key findings

- Ni-doped catalysts showed higher activity at lower temperatures but deactivated faster.
- Zn-doped catalysts improved high-temperature stability and maintained high acetaldehyde selectivity.
- Zn-doped catalysts produced 3.63 g g–1 h–1 acetaldehyde at 290 °C with reduced coke formation.

## Abstract

Nonoxidative ethanol
dehydrogenation opens a pathway for the sustainable
production of acetaldehyde and butadiene. One crucial aspect of producing
butadiene by the Lebedev process is the high-temperature stability
of ethanol to acetaldehyde conversion. However, copper-based catalysts,
despite exhibiting high activity and selectivity, suffer from sintering
and coking and need to be improved for successful industrial applications.
Herein, we show Cu-based (∼2.5 wt %) catalysts doped with Ni
and Zn (0.028–0.36 wt %) to improve the catalytic performance
of nanoparticles. The catalysts were prepared by hydrolytic sol–gel
and dry impregnation methods. STEM analysis determined the nanoparticle
sizes in the 1.9–2.8 nm range. Ni-doped catalysts outperformed
the parent Cu catalysts in ethanol dehydrogenation activity at lower
temperatures (185–220 °C) but suffered from faster deactivation.
The Zn-doped catalysts exhibited improved high-temperature stability.
For these materials, acetaldehyde selectivity fluctuated around ∼90%
and acetaldehyde productivity reached 3.63 g g–1 h–1 at 290 °C and a WHSV of 4.73 h–1. The improved stability of the Zn-doped samples was correlated with
lower coke formation (XPS, TG analysis, and Raman spectroscopy).