Recent advances in core-shell structured catalysts for low-temperature NH3-SCR of NOx

Ammonia selective catalytic reduction (NH₃-SCR) of nitrogen oxides is an effective and well-established technology for NO_x removal, but current commercial denitrification catalysts based on V₂O₅-WO₃/TiO₂ have some obvious disadvantages, including narrow operating temperature windows, toxicity, poor hydrothermal stability, and unsatisfied SO₂/H₂O tolerance. To overcome these drawbacks, it is imperative to investigate new types of highly efficient catalysts. In order to design catalysts with outstanding selectivity, activity, and anti-poisoning ability, core-shell structured materials have been widely applied in the NH₃-SCR reaction, which exhibits numerous advantages including the large surface area, the strong synergy interaction of core-shell materials, the confinement effect, and the shielding effect from the shell layer to protect the core. This review summarizes recent developments of core-shell structured catalysts for NH₃-SCR, including basic classification, synthesis methods, and a detailed description of the performance and mechanisms of each type of catalyst. It is hoped that the review will stimulate future developments in NH₃-SCR technology, leading to novel catalyst designs with improved denitrification performance.

FeCeOx Supported Ni, Sn Catalysts for the High-Temperature Water–Gas Shift Reaction

In this work, the effect of monometallic Ni or Sn and bimetallic NiSn deposition on the activity of FeCeOx catalysts in high-temperature water–gas (HT-WGS) reactions was investigated. It was found that the HT-WGS performance of FeCeOx has significantly improved after the deposition of Sn together with Ni on it. Furthermore, the bimetallic NiSn/FeCeOx catalyst showed higher activity compared to the monometallic Ni/FeCeOx and Sn/FeCeOx catalysts within the tested temperature range (450–600 °C). Although the Ni/FeCeOx catalyst showed methanation activity at a temperature below 550 °C, the NiSn/FeCeOx catalyst suppressed the methane formation to zero in the WGS. Besides, the NiSn/FeCeOx catalyst exhibited an excellent time-on-stream stability without methanation reaction, even at a steam-to-CO ratio as low as 0.8. The combination of Ni and Sn supported on FeCeOx led to a large lattice strain, the formation of NiSn alloy, and a strong synergistic effect between the bimetallic NiSn and FeCeOx mixed oxide support interface. All these features are very important in achieving the best activity and stability of NiSn/FeCeOx in the HT-WGS reaction.

Core–shell structured catalysts for thermocatalytic, photocatalytic, and electrocatalytic conversion of CO2

An in-depth assessment of properties of core–shell catalysts and their application in the thermocatalytic, photocatalytic, and electrocatalytic conversion of CO₂into synthesis gas and valuable hydrocarbons.

High-temperature water gas shift reaction on Ni–Cu/CeO2 catalysts: effect of ceria nanocrystal size on carboxylate formation

The WGS mechanism strongly depends on the Ni–Cu surface composition.

Bimetallic Ni–Cu alloy nanoparticles supported on silica for the water-gas shift reaction: activating surface hydroxyls via enhanced CO adsorption

Strong CO adsorption activates surface OH for enhanced WGS activity.

Sulfur resistant LaxCe1−xNi0.5Cu0.5O3 catalysts for an ultra-high temperature water gas shift reaction

Synergistic effect of Ni–Cu with La₂O₃–CeO₂ for high sulfur resistance in water gas shift reaction.