自支撑过渡金属硫化物/氮掺杂碳纳米管复合薄膜用于持续性水分解

Hydrogen is considered as a clean and renewable energy alternative to fossil fuels in the future. Water electrolysis is a well-established commercial technology for mass production of high-purity hydrogen, while it requires an active, stable and cheap electrocatalyst for hydrogen evolution reaction (HER) to achieve low overpotential and fast kinetics for practical applications. Although Pt-based catalysts show high catalytic performance, they suffer from high cost and the scarcity of Pt. Thus, it is highly desired but still remains a huge challenge to develop such catalysts with superior activity and durability. In this project, we describe the direct growth of interconnected N-doped carbon nanotubes film on carbon cloth (NCNT/CC) via chemical vapour deposition from dicyanodiamine using Co3O4 nanowires array as catalyst. Then, we further develop highly active and stable catalysts containing transition metal dichalcogenides (TMDs) or metal (Co etc.)-doped TMDs hybridized with NCNT/CC (TMDs-NCNT/CC) for HER in alkaline media. More importantly, an alkaline electrolyzer that achieves 20 mA cm-2 at a voltage of 1.5 V, which may be operated by a single-cell alkaline battery, will be fabricated by applying TMDs-NCNT/CC as cathode and NiFe layer double hydroxide (NiFe LDH) as anode. We believe these NCNT film based 3D flexible electrodes will open up new avenues to replace platinum in technologies relevant to renewable energies, such as proton exchange membrane (PEM) electrolyzers and solar photoelectrochemical (PEC) water-splitting cells.

氢气是一种丰富、可再生的清洁燃料，电解水是大规模析氢中最为简单的方法，但需要高效稳定的催化剂来实现低过电位析氢。目前，Pt是最好的析氢催化剂，但价格昂贵导致其无法大规模使用推广。因此，研究开发低成本的新型高效析氢电催化剂具有十分重要意义。本项目将通过化学气相沉积法利用四氧化三钴纳米线阵列和二氰二胺为前驱物制备自支撑氮掺杂碳纳米管薄膜，进而在此薄膜基础上制备过渡金属硫化物或金属原子掺杂过渡金属硫化物的复合薄膜并测试其在碱性条件下电化学析氢性能；运用密度泛函理论揭示复合薄膜的内在协同催化机理；利用镍铁层状双金属氢氧化物为析氧阳极、复合薄膜为析氢阴极设计基于非贵金属催化剂的碱性电解槽以实现低过电位析氢析氧；利用商业化1.5伏干电池为电源实现裸眼观察其析氢析氧现象。该催化剂将有望替代在可再生能源（如质子交换膜电解器和太阳能光电水分离池）等相关科技领域中广泛使用的铂进而为能源发展开辟新途径。

氢气是一种丰富、可再生的清洁燃料，电解水是大规模析氢中最为简单的方法，但需要高效稳定的催化剂来实现低过电位析氢。目前，Pt是最好的析氢催化剂，但价格昂贵导致其无法大规模使用推广。因此，研究开发低成本的新型高效析氢电催化剂具有十分重要意义。本项目将通过化学气相沉积法制备出系列三维自支撑薄膜，进而在此薄膜基础上沉积金属纳米颗粒或金属单元原子掺杂过渡金属硫化物的复合薄膜并测试其在碱性条件下电化学析氢性能；运用密度泛函理论揭示了复合薄膜的内在协同催化机理；设计出基于非贵金属催化剂的碱性电解槽并实现低过电位析氢析氧；利用商业化1.5伏干电池为电源实现裸眼观察其析氢析氧现象。基于该项目我们共发表论文9篇，获得授权专利1项，申请专利2项，国际学术会议邀请报告1次，协助培养青年学术骨干（博士后出站）1名，协助培养博士研究生3名。例如，通过电沉积技术在硫化钼纳米片薄膜上沉积上单原子钌，成功开发了第一类基于单原子钌的薄膜催化剂，密度泛函理论计算证明在硫化钼表面引入单原子钌可显著降低氢吸附的Gibbs自由能，从而显著提高其性能；构建了氧化镍@镍修饰二硫化钨纳米片薄膜电极作为双功能催化剂用于水分解，仅需要电池电压1.49伏达到20 mAcm-2的电流密度；构筑了新型氢氧化镍@镍薄膜电极，密度泛函理论计算证明该薄膜中氢氧化镍和镍间的协同作用有利于氢的化学吸附，进而提高其电解水性能。因此，该系列薄膜催化剂将有望替代在可再生能源（如质子交换膜电解器和太阳能光电水分离池）等相关科技领域中广泛使用的铂进而为能源发展开辟新途径。