Efficient visible-light induced H2 evolution from T-CdxZn1-xS/defective MoS2 nano-hybrid with both bulk twinning homojunctions and interfacial heterostructures

Abstract

Developing high-performance noble-metal-free photocatalysts for solar water splitting is of great urgency to address the growing energy and environmental crises. However, the current photocatalytic efficiency is unsatisfactory due to the low conversion of solar energy. Herein, we prepared a unique hybrid photocatalyst consisting of twinned CdxZn1-xS solid solutions grown with several layers of defect-rich MoS2 nanosheets (T-CdxZn1-xS/MoS2) to achieve a stable and efficient H2 evolution reaction (HER) activity. Noticeably, the alternating zinc blende/wurtzite (ZB/WZ) homojunctions in T-CdxZn1-xS and intimate heterojunctions formed between T-CdxZn1-xS and MoS2 facilitated the efficient separation and transfer of both bulk and surface charge carriers. Moreover, the good visible-light responses of T-CdxZn1-xS and MoS2 as well as the existence of abundant S22− and Mo5+ active species in defective MoS2 nanosheets also contributed significantly to the activity improvement of T-CdxZn1-xS/MoS2. Benefiting from the above advantages, T-CdxZn1-xS/MoS2 exhibited superior HER rates of 37.22 mmol∙h-1 g-1 in lactic acid solution and 69.25 mmol∙h-1 g-1 in Na2S/Na2SO3 solution, corresponding to the apparent quantum yield (AQY) of 36.3 % and 55.2 % at 420 nm, respectively. The HER capability of T-CdxZn1-xS/MoS2 exceeded that of Pt/T-CdxZn1-xS and most CdS-based photocatalysts reported previously. Our findings will facilitate the exploitation of advanced nanomaterials for sustainable energy conversion and utilization.