Plasma-chemical preparation of nanostructured catalysts for low-temperature steam conversion of carbon monoxide: catalytic activity

The "warm walls" (WW) plasma-chemical reactors (PCR) synthesized catalyst samples (types LTC-1–3) give up by activity compared to their industrial analogues; and these synthesized in PCR with “cold walls” (CW) (types LTC-7–9) have a commensurable activity compared to those of the industrial catalysts used by the Bulgarian company CHIMCO-Vratza. Their activities were defined by using a model gas simulating the industrial one for temperatures and a volume rate of the steam–gas mixture similar to those used in the industrial process of low-temperature steam conversion of CO. The enhanced catalytic activity of the plasma-chemically synthesized samples is owing to: the faulty crystal lattice structure of the catalytically active phases; the nanodispersed sample composition (the crystal sizes of the catalytically active phases ranges from 10 to 40 nm); the presence of Cu2O in the fresh samples, apart form the presence of CuO; the content of cuprous oxides-30–38 mass%; the even distribution of the ultradispersed components, the high porosity, specific surface and dispersity of the phases. Due to the bonding of a portion of the elemental Cu in the CuAl2O4 spinel crystal lattice, the plasma-chemically synthesized samples type LTC have a high thermal resistance which exceeds that of their conventional industrial analogues. The high specific surface of the plasma-chemically synthesized samples for low-temperature steam conversion of CO, their homogenous chemical composition, high formation rate of their active surface by reduction, high activity and thermal resistance, represent a precondition to extend the investigation on developing a plasma-chemical technology for their industrial synthesis in the catalyst workshops.