Efficient Charge Transfer at a Homogeneously Distributed (NH4)2Mo3S13 / WSe2 Heterojunction for Solar Hydrogen Evolution

In the present work we demonstrate a record photocurrent density of 5.6 mA cm^-2 at 0 V_RHE for WSe₂ photocathodes coated with an effective/earth abundant catalyst - ammonium thiomolybdate (NH₄)₂Mo₃S₁₃ (ATM). The photocurrent density can be tuned by optimizing the WSe₂ film thickness. The features of this new combination (NH₄)₂Mo₃S₁₃ / WSe₂ and its performance for solar hydrogen evolution is discussed in the manuscript. Our new finding is that the ATM can be used as a photocatalyst, not only as an electrocatalyst known up to date. The results further expand and develop the field of the transition metal dichalcogenides especially in the context of the solar hydrogen evolution. This work is an important milestone towards large scale photocathodes using earth abundant elements.