Thirumalaisamy Logu, Wei Zhengfei, Davies Katherine Rebecca, Allan Michael G, McGettrick James, Watson Trystan, Kuehnel Moritz F, Pitchaimuthu Sudhagar
SPECIFIC, Materials Research Centre, Faculty of Science and Engineering, Swansea University (Bay Campus), Swansea SA1 8EN, U.K.
Department of Physics, G T N Arts College, Dindigul, Tamil Nadu 624005, India.
ACS Sustain Chem Eng. 2024 Feb 12;12(8):3044-3060. doi: 10.1021/acssuschemeng.3c06528. eCollection 2024 Feb 26.
The heterostructure WO/BiVO-based photoanodes have garnered significant interest for photoelectrochemical (PEC) solar-driven water splitting to produce hydrogen. However, challenges such as inadequate charge separation and photocorrosion significantly hinder their performance, limiting overall solar-to-hydrogen conversion efficiency. The incorporation of cocatalysts has shown promise in improving charge separation at the photoanode, yet mitigating photocorrosion remains a formidable challenge. Amorphous metal oxide-based passivation layers offer a potential solution to safeguard semiconductor catalysts. We examine the structural, surface morphological, and optical properties of two-step-integrated sputter and spray-coated TiO thin films and their integration onto WO/BiVO, both with and without NiOOH cocatalyst deposition. The - experiments reveal that the NiOOH cocatalyst enhances the photocurrent density of the WO/BiVO photoanode in water splitting reactions from 2.81 to 3.87 mA/cm. However, during prolonged operation, the photocurrent density degrades by 52%. In contrast, integrated sputter and spray-coated TiO passivation layer-coated WO/BiVO/NiOOH samples demonstrate a ∼88% enhancement in photocurrent density (5.3 mA/cm) with minimal degradation, emphasizing the importance of a strategic coating protocol to sustain photocurrent generation. We further explore the feasibility of using natural mine wastewater as an electrolyte feedstock in PEC generation. Two-compartment PEC cells, utilizing both fresh water and metal mine wastewater feedstocks exhibit 66.6 and 74.2 μmol/h cm hydrogen generation, respectively. Intriguingly, the recovery of zinc (Zn) heavy metals on the cathode surface in the mine wastewater electrolyte is confirmed through surface morphology and elemental analysis. This work underscores the significance of passivation layer and cocatalyst coating methodologies in a sequential order to enhance charge separation and protect the photoanode from photocorrosion, contributing to sustainable hydrogen generation. Additionally, it suggests the potential of utilizing wastewater in electrolyzers as an alternative to freshwater resources.
基于异质结构WO/BiVO的光阳极在光电化学（PEC）太阳能驱动水分解制氢方面引起了广泛关注。然而，诸如电荷分离不足和光腐蚀等挑战严重阻碍了它们的性能，限制了整体太阳能到氢能的转换效率。引入助催化剂在改善光阳极的电荷分离方面显示出前景，但减轻光腐蚀仍然是一个巨大的挑战。基于非晶金属氧化物的钝化层为保护半导体催化剂提供了一种潜在的解决方案。我们研究了两步集成溅射和喷涂的TiO薄膜的结构、表面形态和光学性质，以及它们在有无NiOOH助催化剂沉积情况下与WO/BiVO的集成情况。实验表明，NiOOH助催化剂在水分解反应中使WO/BiVO光阳极的光电流密度从2.81 mA/cm提高到3.87 mA/cm。然而，在长时间运行过程中，光电流密度下降了52%。相比之下，集成溅射和喷涂TiO钝化层的WO/BiVO/NiOOH样品光电流密度提高了约88%（达到5.3 mA/cm）且降解最小，强调了采用战略涂层方案以维持光电流产生的重要性。我们进一步探索了在PEC发电中使用天然矿废水作为电解质原料的可行性。利用淡水和金属矿废水原料的两室PEC电池分别表现出66.6和74.2 μmol/h cm的产氢量。有趣的是，通过表面形态和元素分析证实了在矿废水电解质中阴极表面锌（Zn）重金属的回收。这项工作强调了按顺序采用钝化层和助催化剂涂层方法以增强电荷分离并保护光阳极免受光腐蚀对于可持续制氢的重要性。此外，它还表明了在电解槽中利用废水替代淡水资源的潜力。
