Shi Li, Benetti Daniele, Li Faying, Wei Qin, Rosei Federico
Centre for Energy, Materials and Telecommunications, Institut National de la Recherche Scientifique, 1650 Boul. Lionel-Boulet, Varennes, QC, J3X1P7, Canada.
Key Laboratory of Interfacial Reaction & Sensing Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, P. R. China.
Small. 2022 Jun;18(24):e2201815. doi: 10.1002/smll.202201815. Epub 2022 May 6.
Nickel oxide (NiO) is a promising p-type material for a wide range of optoelectronic devices, as well as photocathode for photoelectrochemical (PEC) water splitting. However, traditional NiO photoelectrodes exhibit a wide bandgap (3.6 eV), intrinsic poor electrical conductivity, and low surface area, leading to low PEC systems performance. Herein, the authors explore a Ni-based metal-organic framework (MOF) template method to obtain hierarchical hollow spheres of carbon/NiO nanostructure by successive carbonization and oxidation treatments. After sensitization with core and core-shell quantum dots (QDs), the optimized NiO-photocathode exhibits a maximum current density of -93.6 µA cm at 0 V versus RHE (reversible hydrogen electrode) in neutral pH (6.8) and -285 µA cm at -0.4 V versus RHE. Compared to pure NiO and single-core CdSe QDs, a 2.2-fold increase in photocurrent can be obtained. The improvement in the performance of this hybrid is not only due to the high surface area for loading QDs and light scattering, but also to the presence of a highly conductive carbon matrix that promotes fast charge transfer. The proposed MOFs-based NiO/carbon photocathode sensitized with QDs can be an effective strategy to improve the efficiency of metal oxide-based PEC systems for hydrogen generation.
氧化镍（NiO）是一种适用于多种光电器件的有前景的p型材料，也是用于光电化学（PEC）水分解的光阴极。然而，传统的NiO光电极具有较宽的带隙（3.6电子伏特）、固有的低电导率和低表面积，导致PEC系统性能较低。在此，作者探索了一种基于镍的金属有机框架（MOF）模板法，通过连续的碳化和氧化处理来获得碳/ NiO纳米结构的分级空心球。在用核量子点和核壳量子点（QD）敏化后，优化后的NiO光阴极在中性pH值（6.8）下相对于可逆氢电极（RHE）在0 V时表现出-93.6 μA/cm²的最大电流密度，在-0.4 V相对于RHE时为-285 μA/cm²。与纯NiO和单核CdSe量子点相比，光电流可提高2.2倍。这种复合材料性能的提高不仅归因于用于负载量子点的高表面积和光散射，还归因于促进快速电荷转移的高导电碳基质的存在。所提出的用量子点敏化的基于MOF的NiO/碳光阴极可能是提高基于金属氧化物的PEC制氢系统效率的有效策略。
