Abstract
? 2022 Elsevier B.V.Maximumly increasing the number of active sites is crucial to improve the H2-evolution efficiency of cocatalyst. Herein, a rich-active-site regulation strategy by the synergism of unsaturated selenium enrichment and amorphization is developed to precisely construct unsaturated selenium-enriched MoSe2+x amorphous nanoclusters onto the TiO2 via a mild photoinduced co-reduction route by using MoCl5 and dibenzyl diselenide as the precursors. The resulting a-MoSe2+x exposes more unsaturated Se atoms (46.5%) because of its unsaturated Se-enriched configuration, highly irregular arrangement, and ultrasmall size (0.3 ?1 nm). Photocatalytic tests show that the a-MoSe2+x/TiO2(3 wt%) achieves an optimal H2-evolution rate (4984.46 μmol h?1 g?1, AQE = 23.90%), with the 4.51-fold enhancement relative to that of c-MoSe2/TiO2. Hence, a rich unsaturated Se-mediated H2-evolution mechanism is proposed, namely, the abundant unsaturated Se atoms as the active sites can not only provide sufficient proton-adsorption-centers to enrich H+, but also present an outstanding catalytic efficiency to fleetly convert H+ to H2.
NSTL
Elsevier