摘要
The increasing exploration of renewable and clean power sources have driven the development of highly active materials for photoelectrochemical （PEC） water splitting. However, it is still a great challenge to enhance the charge utilization. Herein, we report a facile method to fabricate composite photoanode with porous BiVO4 film as the photon absorber and layered double hydroxide （LDH） nanosheet arrays as the oxygen-evolution cocatalysts （OECs）. The as-prepared BiVO4/NiFe-LDH photoanode shows an excellent performance for PEC water splitting benefitting from the synergistic effect of the superior charge separation efficiency facilitated by porous BiVO4 film and the excellent water oxidation activity resulting from LDH nanosheet arrays. A photocurrent density is 4.02 mA cm^-2 at 1.23 V vs. the reversible hydrogen electrode （RHE）. Furthermore, the O2 evolution rate at the surface of BiVO4/NiFe-LDH photoanode is as high as 29.6 μmol h^-1 cm^-2 and the high activity for water oxidation is maintained for over 30 h. Impressively, the performance of the as-fabricated composite photoanode for PEC water splitting can be further enhanced through incorporating a certain amount of Co^2＋ cation into NiFe-LDH as OEC. The photocurrent density is achieved up to 4.45 mA cm^-2 at 1.23 V vs. RHE. This value is the highest yet reported for un-doped BiVO4-based photoanodes so far.
可再生清洁能源的不断探索推动了高活性的光电催化分解水材料的开发.然而,提高光电材料的载荷子利用率仍是材料与光电化学领域的一个重要挑战.本文报道了一种简单的方法来构筑由多孔BiVO_4薄膜作为光吸收剂和水滑石(LDH)纳米片阵列作为产氧助催化剂(OECs)的复合光电阳极.由于多孔BiVO_4膜高效的电荷分离效率和LDH纳米片阵列优异的水氧化活性协同效应,所制备的BiVO_4/NiFe-LDH光电阳极展现出优异的光电催化分解水性能,在1.23 V(相对于可逆氢电极(RHE))下光电流密度达4.02 mA cm^(-2).此外,BiVO_4/NiFe-LDH光阳极表面的O_2产生速率高达29.6μmol h.1 cm^(-2),并且活性可以维持30小时以上.此外,通过将一定量的Co^(2+)离子掺杂到NiFe-LDH中作为OEC,可以进一步增强复合光电阳极的性能.在1.23 V(相对于RHE)下,光电流密度高达4.45 mA cm^(-2),该值是目前报道的基于未掺杂BiVO_4光阳极的最高值.
基金
supported by the National Natural Science Foundation of China(21422104)
the Key Project of Natural Science Foundation of Tianjin City(16JCZDJC30600)
