Abstract The photocatalytic decomposition of water to produce hydrogen is an important process, through which solar energy can be converted to chemical energy. Non-precious metal phosphides have quietly attracted attention as an emerging inexpensive photocatalyst. In this study, we reported that a CoP/CeVO4 hybrid photocatalyst exhibited high hydrogen evolution efficiency owing to EY (eosin Y) sensitization under visible light irradiation for the first time, and the amount of generated hydrogen reached 444.6 μmol in 5 h. The CoP/CeVO4 nanohybrids were synthesized by a simple chemical precipitation method. The coupling of CoP and CeVO4 with ZIF-9 as a precursor could be completed in one step. The CeVO4 particles were firmly attached to the surface of the CoP particles to form a “small point” to “big point” heterojunction. The results of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, EDX, and transmission electron microscopy showed the formation of CoP and CeVO4 nanoparticles and the structure of the composite. Based on a detailed analysis of the Mott-Schottky plot, the UV-vis diffuse reflectance spectra, photocurrent-time (it) curve, Tafel curve, Nyquist curve (EIS), linear volt-ampere curve (LSV), and steady-state fluorescence spectra were studied. The time-resolved photoluminescence measurements indicated that the reason for the high-efficiency hydrogen evolution of CoP/CeVO4 was that the bands of CoP and CeVO4 were bent due to the existence of the Schottky barrier, and a heterojunction was formed between CoP and CeVO4, which generated an internal electric field and accelerated the charge transfer. In addition, the synergistic effect between CoP and CeVO4 provided a new hydrogen-evolution activity center for each of them. The improved carrier separation efficiency and the decrease in the photo-generated recombination rate led to the excellent photocatalytic hydrogen-evolution activity of the CoP/CeVO4 composite catalyst. This work provides a new strategy for modulating the electronic structure and carrier behavior of transition metal phosphide photocatalysts.

中文翻译：

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ZIF-9(Co) 衍生的磷化钴和 CeVO4 异质结的独特协同效应可实现高效析氢

摘要 水的光催化分解制氢是太阳能转化为化学能的重要过程。非贵金属磷化物作为一种新兴的廉价光催化剂已经悄然引起了人们的关注。在这项研究中，我们首次报道了 CoP/CeVO4 杂化光催化剂在可见光照射下由于 EY（曙红 Y）敏化而表现出高析氢效率，并且在 5 小时内产生的氢气量达到 444.6 μmol。CoP/CeVO4 纳米杂化物是通过简单的化学沉淀法合成的。CoP和CeVO4与ZIF-9作为前驱体的偶联可以一步完成。CeVO4 颗粒牢固地附着在 CoP 颗粒的表面，形成“小点”到“大点”的异质结。X 射线衍射、X 射线光电子能谱、扫描电子显微镜、EDX 和透射电子显微镜的结果显示了 CoP 和 CeVO4 纳米粒子的形成以及复合材料的结构。基于 Mott-Schottky 图的详细分析，UV-vis 漫反射光谱、光电流-时间 (it) 曲线、Tafel 曲线、奈奎斯特曲线 (EIS)、线性伏安曲线 (LSV) 和稳态研究了荧光光谱。时间分辨光致发光测量表明，CoP/CeVO4高效析氢的原因是由于肖特基势垒的存在，CoP和CeVO4的能带发生弯曲，CoP和CeVO4之间形成异质结，产生内部电场并加速电荷转移。此外，CoP 和 CeVO4 之间的协同效应为它们各自提供了一个新的析氢活动中心。载流子分离效率的提高和光生复合率的降低导致 CoP/CeVO4 复合催化剂具有优异的光催化析氢活性。这项工作为调节过渡金属磷化物光催化剂的电子结构和载流子行为提供了一种新策略。