Hydrogen, serving as a clean, sustainable energy source, may be mainly produced from electrolysis water. Herein, we report cobalt disulphide encapsulated in self-catalyzed carbon nanotubes (S, N-CNTs/CoS₂@Co) serving as a bifunctional catalyst, which exhibits excellent hydrogen evolution reaction performance (10.0 mA cm⁻² at 0.112 V, and low Tafel slope for 104.9 mV dec⁻¹) and oxygen evolution reaction performance (10.0 mA cm⁻² at 1.57 V, and low Tafel slope for 76.1 mV dec⁻¹), meanwhile with a strong stability at various current densities. In-depth study reveals that the excellent catalytic properties can be mainly attributed to the increased catalytic sites induced by S, N co-doping, the improved electronic conductivity derived from the carbon nanotubes, and Mott-Schottky effect between the metal cobalt and semiconductive cobalt disulfide. Notably, when the bifunctional catalysts are applied to overall water splitting, a low potential of 1.633 V at the current density of 10.0 mA cm⁻² is achieved, which can compete with the precious metal catalyst benchmarks in alkaline media, demonstrating its promising practicability in the realistic water splitting application. This work elucidates a practicable way to the design of transition metal and nano-carbon composite catalysts for a broad application in the fields of energy chemistry.

氢气作为一种清洁、可持续的能源，可能主要由电解水生产。在此，我们报告了封装在自催化碳纳米管（S，N-CNTs/CoS ₂ @Co）中的二硫化钴作为双功能催化剂，表现出优异的析氢反应性能（10.0 mA cm ^-2在 0.112 V 和低104.9 mV dec ^-1的 Tafel 斜率）和析氧反应性能（1.57 V 时为 10.0 mA cm ^{-2，76.1 mV dec -1}的低 Tafel 斜率)，同时在各种电流密度下具有很强的稳定性。深入研究表明，优异的催化性能主要归因于S、N共掺杂诱导的催化位点增加、碳纳米管电子电导率的提高以及金属钴和半导体钴之间的莫特-肖特基效应二硫化物。值得注意的是，当双功能催化剂应用于全水分解时，在 10.0 mA cm ^{-2的电流密度下，1.633 V 的低电位}实现了可以与碱性介质中的贵金属催化剂基准竞争，证明其在实际水分解应用中具有广阔的实用性。这项工作阐明了一种可行的方法来设计过渡金属和纳米碳复合催化剂，以广泛应用于能源化学领域。