Sulfur-substituted and zinc-doped In(OH)3: A new class of catalyst for photocatalytic H2 production from water under visible light illumination

Abstract Sulfur-substituted In(OH) 3 [hereafter denoted as In(OH) y S z ] and Zn-doped In(OH) y S z [hereafter denoted as In(OH) y S z :Zn] are synthesized in an aqueous solution of ethylenediamine via the hydrothermal method. The photoactivities of these catalysts for H 2 production are investigated in the presence of Na 2 S and Na 2 SO 3 sacrificial reagent under visible light illumination ( λ > 420 nm ). The absorption edge of In(OH) y S z shifted monotonically from 240 nm for In(OH) 3 to 570 nm for In(OH) y S z when the atomic ratio of S/In in the synthesis solution is increased from 0 to 2.0. But the absorption edge of In(OH) y S z :Zn shifted from 570 to 470 nm as the atomic ratio of Zn/In in the synthesis solution was increased from 0 to 1.0. The catalyst In(OH) y S z is active for H 2 production, with an average rate of H 2 of 0.9–1.8 μmol/h, under visible light illumination. The photoactivity of In(OH) y S z is enhanced by doping with Zn 2+ . The rate of H 2 production is 35.8 and 67 μmol/h on 2wt% Pt-loaded In(OH) y S z :Zn catalyst when X = 0.2 and 0.5, respectively, corresponding to a quantum efficiency of 0.32 and 0.59% at 420 ± 10 nm , respectively.