State Key Laboratory of Advanced Technology for Materials Synthesis and Processing , Wuhan University of Technology , Wuhan 430070 , P. R. China.
Department of Physics, Faculty of Science , King Abdulaziz University , Jeddah 21589 , Saudi Arabia.
ACS Appl Mater Interfaces. 2018 Jul 5;10(26):22311-22319. doi: 10.1021/acsami.8b06272. Epub 2018 Jun 21.
Water oxidation is the key process for many sustainable energy technologies containing artificial photosynthesis and metal-air batteries. Engineering inexpensive yet active electrocatalysts for water oxidation is mandatory for the cost-effective generation of solar fuels. Herein, we propose a novel hierarchical porous Ni-Co-mixed metal sulfide (denoted as NiCoS) on TiCT MXene via a metal-organic framework (MOF)-based approach. Benefiting from the unique structure and strong interfacial interaction between NiCoS and TiCT sheets, the hybrid guarantees an enhanced active surface area with prominent charge-transfer conductivity and thus a superior activity toward oxygen evolution reactions (OERs). Impressively, the hierarchical NiCoS in the hybrid is converted to nickel/cobalt oxyhydroxide-NiCoS assembly (denoted as NiCoOOH-NiCoS) by OER measurement, where NiCoOOH on the surface is confirmed as the intrinsic active species for the consequent water oxidation. The hybrid material is further applied to an air cathode for a rechargeable zinc-air battery, which exhibits low charging/discharging overpotential and long-term stability. Our work underscores the tuned structure and electrocatalytic OER performance of MOF derivatives by the versatility of MXenes and provides insight into the structure-activity relationship for noble metal-free catalysts.
水氧化是许多包含人工光合作用和金属空气电池的可持续能源技术的关键过程。对于具有成本效益的太阳能燃料的产生，必须设计廉价但活性高的用于水氧化的电催化剂。在此，我们通过基于金属有机骨架（MOF）的方法，在 TiCT MXene 上提出了一种新型的分层多孔 Ni-Co 混合金属硫化物（表示为 NiCoS）。得益于 NiCoS 和 TiCT 片之间的独特结构和强界面相互作用，该混合物保证了增强的活性表面积，具有突出的电荷转移导电性，因此对氧析出反应（OER）具有优异的活性。令人印象深刻的是，混合体中的分层 NiCoS 通过 OER 测量转化为镍/钴氢氧化物-NiCoS 组装体（表示为 NiCoOOH-NiCoS），其中表面上的 NiCoOOH 被确认为随后水氧化的本征活性物质。该混合材料进一步应用于可充电锌空气电池的空气阴极，其具有低的充电/放电过电位和长期稳定性。我们的工作强调了通过 MXenes 的多功能性对 MOF 衍生物进行调整结构和电催化 OER 性能，并深入了解了无贵金属催化剂的结构-活性关系。
