A method of making a filter article having a honeycomb substrate having adsorbent filled channels, including: sealing the first end of a porous, cellular honeycomb substrate; filling the channels of the cellular honeycomb substrate with a dry adsorbent source material; sealing the second end of the filled honeycomb to form a sealed honeycomb; contacting the sealed honeycomb and water for a time sufficient to convert the dry precursor material in-situ to a paste; removing the seals from the first and second ends; and heating the contacted honeycomb to convert the paste to an adsorbent. Also disclosed is a filter article having a honeycomb substrate having adsorbent filled channels and methods of using the article.