Coherent nanointerface between light-harvesting and catalytic transition metal sulfides for efficient photochemical conversion

Creating atomically coherent interfaces can sharpen the physiochemical properties and functionalities of nanomaterials for efficient energy conversion via manipulating the charge flow. While coherent interfaces can be built between transition metal dichalcogenides with structural similarities and weak interlayer van der Waals interactions, it remains challenging to realize interfacial coherency with more generic transition metal chalcogenides via cost-effective wet chemical routes. Here we establish a coherent CdS(010)|CoS(010) interface via in-situ heteroepitaxial growth of CoS nanoflakes onto CdS nanowires. The uniform and oriented distribution of CoS nanoflakes on the CdS nanowires features an interesting “leaves-on-a-branch” nano-architecture with coherent interface and well-aligned energy levels, allowing efficient separation of photoexcited charge carriers. Combined with the outstanding proton reduction kinetics of the CoS “nanoleaves”, striking photochemical solar-to-hydrogen conversion performance can be obtained. Our findings provide a viable design strategy of nanojunctions with atomic level coherency and great application prospect in catalysis, nanoelectronics and many others.