Abstract：
The persistent hurdles of charge rapid recombination, inefficient use of light and utilization of sacrificial reagents have plagued the field of photocatalytic hydrogen evolution (PHE). In this research, tiny MoO2 nanoparticles of 10 nm in diameter were prepared through a straightforward solvothermal approach with a specific ratio of oleylamine and oleic acid as stabilizers. The critical factor in the synthesis process was found to be the ratio of oleylamine to oleic acid. Moreover, a two-phase interface assembly method facilitated the uniform deposition of MoO2 onto CdS nanorods. Due to the localized plasmonic-thermoelectric effect on the surface of MoO2 along with its abundant oxygen vacancies, the composite catalyst exhibited outstanding photo-utilization efficiency and an abundance of active sites. The CdS-MoO2 composite displayed a unique photochemical property in transforming lactic acid into pyruvic acid and generating hydrogen simultaneously. After exposure to artificial sunlight for 4 h, significant values of 4.7 and 3.7 mmol⋅g-1⋅h-1 were achieved for hydrogen production and pyruvic acid formation, respectively, exceeding CdS alone by 3.29 and 4.02-fold, while the selectivity of pyruvic acid was 95.68 %. Furthermore, the S-Scheme electron transport mechanism in the composites was elucidated using Electron Paramagnetic Resonance (EPR) spectroscopy, radical trapping experiments, energy band structure analysis, and the identification of critical intermediates in the process of selective oxidation. This work sheds light on the design and preparation of high-performance photocatalysts for biorefining coupled with efficient hydrogen evolution.
摘要：
电荷快速重组的持续障碍，光的低效使用和牺牲试剂的利用一直困扰着光催化析氢(PHE)领域。在这项研究中,通过简单的溶剂热法制备直径为10nm的微小MoO2纳米颗粒，并以特定比例的油胺和油酸作为稳定剂。发现合成过程中的关键因素是油胺与油酸的比例。此外，两相界面组装方法促进了MoO2在CdS纳米棒上的均匀沉积。由于MoO2表面的局部等离子体热电效应及其丰富的氧空位，复合催化剂表现出优异的光利用效率和丰富的活性位点。CdS-MoO2复合材料在将乳酸转化为丙酮酸并同时产生氢气方面表现出独特的光化学性质。暴露于人造阳光下4小时后，氢气生产和丙酮酸形成的显著值分别为4.7和3.7mmol·g-1·h-1，分别,单独超过CdS3.29倍和4.02倍，丙酮酸的选择性为95.68%。此外，使用电子顺磁共振（EPR）光谱阐明了复合材料中的S-Scheme电子传输机制，自由基捕获实验,能带结构分析，以及选择性氧化过程中关键中间体的确定。这项工作为设计和制备用于生物精炼和高效析氢的高性能光催化剂提供了启示。
