What Specific Effects Does Humidity Have on the Catalytic Performance of Hopcalite?

1. Physical coverage of active sites

The CO catalytic reaction of Hopcalite relies on surface Cu²⁺ and Mn³⁺ active sites. Under high humidity, water molecules preferentially adsorb on these sites and form a dense water film, directly blocking the contact between O₂, CO and active sites, leading to stagnation of the catalytic reaction.

In a mine emergency drill simulating a high-humidity environment (RH=60%), the CO purification efficiency of ordinary Hopcalite dropped sharply from 98% to 40%, mainly because active sites were covered by a water film and could not function.

2. Pore blockage and reduced specific surface area

Hopcalite is a porous material, and its microporous structure provides diffusion channels for CO and O₂. In high-humidity environments, water vapor enters the micropores and causes capillary condensation, filling the channels and sharply increasing gas diffusion resistance. The catalyst changes from high-efficiency to low-efficiency or even complete failure.

In a waste gas treatment project at an electronics factory in southern China, during hot and humid summer weather (RH=75%), Hopcalite filter media became clogged after only 3 days of operation, CO removal efficiency decreased significantly, requiring frequent replacement.

3. Irreversible deactivation due to crystal structure damage

Under high humidity, CuO and MnO₂ undergo hydration and hydroxylation reactions, forming inert species such as Cu(OH)₂ and MnO(OH), which destroy the original Cu-Mn composite active structure. This change is partially irreversible; activity cannot be fully restored even after drying.

Laboratory tests showed that after exposing Hopcalite to RH=80% for 72 hours, its catalytic efficiency recovered only to 60% of the original level after drying, and its service life was greatly shortened.

4. Inhibition of catalytic reaction and increased light-off temperature

Hopcalite can efficiently catalyze CO at room temperature under dry conditions. When RH > 45%, CO conversion efficiency drops drastically, and heating above 80℃ is required to initiate the reaction.

Humidity also has a clear threshold: performance is stable when RH < 30%, and almost complete deactivation occurs when RH > 70%. Repeated moisture absorption and drying accelerate catalyst pulverization and sintering, shortening the service life by several times compared with dry environments.

Author: Hazel

Date: 2026-03-11