Construction of cost-efficient and high-performance overall water splitting electrocatalysts for generating hydrogen and oxygen has recently received increasing research attention. Herein, hierarchical CoS₂/MoS₂ (CMS) nanoflakes were successfully decorated on graphene (denoted as CMSGr) as an efficient electrocatalyst for overall water splitting. Owing to the distinct hierarchical flakes morphology, and optimized interfacial microenvironment between CoS₂ and MoS₂, the fabricated CMSGr composites exhibit enhanced hydrogen and oxygen evolution reaction (HER/OER) activity. In particular, the optimized CMSGr-3 electrocatalyst presents the small overpotentials of 53 and 255 mV for HER and OER, and a low voltage of 1.55 V for overall water splitting in alkaline media under 10 mA cm⁻². Theoretical calculations confirm that introducing CoS₂ into MoS₂ can greatly tune the electronic structure and optimize the adsorption energy during the water splitting. This work demonstrates that tuning the interfacial microenvironment of the binary metal sulfide composites is an effective route for developing high-performance water splitting electrocatalysts.

构建具有成本效益和高性能的整体水分解电催化剂来产生氢气和氧气最近受到越来越多的研究关注。在此，分层CoS ₂ /MoS ₂ (CMS)纳米片成功地装饰在石墨烯（表示为CMSGr）上，作为整体水分解的有效电催化剂。由于独特的分层薄片形态，以及 CoS ₂和 MoS _{2之间优化的界面微环境}，所制造的 CMSGr 复合材料表现出增强的析氢反应（HER/OER）活性。特别是，优化的CMSGr-3电催化剂对于HER和OER表现出53和255 mV的小过电位，以及在10 mA cm -2 的碱性介质中整体水分解的1.55 V的低^电压。理论计算证实，将CoS ₂引入MoS ₂中可以极大地调节电子结构并优化水分解过程中的吸附能。这项工作表明，调节二元金属硫化物复合材料的界面微环境是开发高性能水分解电催化剂的有效途径。