Feng Fan, Mitoraj Dariusz, Oseghe Ekemena, Streb Carsten, Beranek Radim
Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, Mainz 55128, Germany.
Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, Ulm 89081, Germany.
ACS Appl Mater Interfaces. 2025 Jan 15;17(2):3665-3675. doi: 10.1021/acsami.4c21125. Epub 2024 Dec 30.
Doping and surface-modification are well-established strategies for the performance enhancement of bismuth vanadate (BiVO) photoanodes in photoelectrochemical (PEC) water splitting devices. Herein, a "double-use" strategy for the development of high-performance BiVO photoanodes for solar water splitting is reported, where a molecular cobalt-phosphotungstate (CoPOM = Na[Co(HO)(PWO)]) is used both as a bulk doping agent as well as a surface-deposited water oxidation cocatalyst. The use of CoPOM for bulk doping of BiVO is shown to enhance the electrical conductivity and improve the charge separation efficiency, resulting in the enhancement of the maximum applied-bias photoconversion efficiency (ABPE) by a factor of ∼18 to 0.54% at 0.87 V vs. RHE, as compared to pristine BiVO (0.03% at 1.04 V vs. RHE). The ratio of W/Co on the surface of the photoanode is related to the activity and stability. In addition, modification of CoPOM-doped BiVO with CoPOM as a surface cocatalyst enhances the hole extraction and improves the water oxidation kinetics, resulting in the overall enhancement of the ABPE to 0.79% (at 0.82 V vs. RHE), i.e., by a factor of ∼26 with respect to pristine BiVO. This study establishes the "double-use" strategy involving CoPOMs as an effective, straightforward, and easily scalable approach for the development of high-quality photoanodes for solar water splitting and highlights the future potential of utilizing well-designed polyoxometalates as precursors for the synthesis of energy materials.
掺杂和表面改性是提高钒酸铋（BiVO）光阳极在光电化学（PEC）水分解装置中性能的成熟策略。本文报道了一种用于开发高性能BiVO光阳极以进行太阳能水分解的“两用”策略，其中分子钴磷钨酸盐（CoPOM = Na[Co(HO)(PWO)]）既用作体相掺杂剂，又用作表面沉积的水氧化助催化剂。结果表明，使用CoPOM对BiVO进行体相掺杂可提高电导率并改善电荷分离效率，与原始BiVO（相对于可逆氢电极（RHE）在1.04 V时为0.03%）相比，在相对于RHE为0.87 V时，最大外加偏压光转换效率（ABPE）提高了约18倍，达到0.54%。光阳极表面的W/Co比例与活性和稳定性有关。此外，用CoPOM作为表面助催化剂对CoPOM掺杂的BiVO进行改性可增强空穴提取并改善水氧化动力学，从而使ABPE总体提高到0.79%（相对于RHE在0.82 V时），即相对于原始BiVO提高了约26倍。本研究确立了涉及CoPOM的“两用”策略，这是一种有效、直接且易于扩展的方法，用于开发用于太阳能水分解的高质量光阳极，并突出了利用精心设计的多金属氧酸盐作为合成能源材料前体的未来潜力。
