Molybdenum and its compounds (ammonium molybdate, sodium molybdate, etc.) can be added as a catalyst during pulp treatment by hydrogen peroxide in an acidic medium [4]. It was shown by the example of straw pulp bleaching that addition of phosphomolybdic acid to hydrogen peroxide during acidic preliminary treatment, has increased the whiteness of pulp by 4.8% ISO compared to bleaching without a catalyst [6].