[2] The procedure involves first preparing a platinum nitrate which is then heated to expel nitrogen oxides.

Platinum can be recovered from spent catalyst by conversion to ammonium chloroplatinate using aqua regia followed by ammonia.

In Adams' own words: "...Several of the problems I assigned my students involved catalytic reduction.

For this purpose we were using as a catalyst platinum black made by the generally accepted best method known at the time.

The students had much trouble with the catalyst they obtained in that frequently it proved to be inactive even though prepared by the same detailed procedure which resulted occasionally in an active product.