利用三元合金保护和催化的硅光阳极与廉价硅太阳能电池相结合实现12.0%的太阳能制氢效率  

Achieving 12.0%Solar-to-Hydrogen Efficiency with a Trimetallic-Layer-Protected and Catalyzed Silicon Photoanode Coupled with an Inexpensive Silicon Solar Cell

作　　者：何凌云 洪欣 王亦清 邢众航 耿嘉峰 郭鹏慧 苏进展 沈少华 Lingyun He;Xin Hong;Yiqing Wang;Zhonghang Xing;Jiafeng Geng;Penghui Guo;Jinzhan Su;Shaohua Shen(International Research Center for Renewable Energy,State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]International Research Center for Renewable Energy,State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China

出　　处：《Engineering》2023年第6期128-137,M0006,共11页工程（英文）

基　　金：supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(51888103);Shaohua Shen is grateful to the National Natural Science Foundation of China(52225606);the Fundamental Research Funds for the Central Universities;the Youth Innovation Team of Shaanxi Universities。

摘　　要：n型硅(n-Si)表面在水溶液中容易被氧化和钝化,导致其在光电化学(PEC)分解水的析氧反应(OER)动力学缓慢。本工作通过欠电位沉积成功地在p^(+)n-Si基底上电沉积了三金属Ni_(0.9)Fe_(0.05)Co_(0.05)保护层。制备的Ni_(0.9)Fe_(0.05)Co_(0.05)/p^(+)n-Si光阳极具有优异的稳定性和PEC水氧化活性,具有相对低的OER起始电位(相对于可逆氢电极电势(RHE)仅为0.938 V),并且在1.23 V vs.RHE电位时具有较高的光电流密度(33.1 m A·cm^(-2)),显著优于Ni/p^(+)n-Si光阳极。工作证明了Fe在Ni层的掺杂会在Ni_(0.9)Fe_(0.05)Co_(0.05)/p^(+)n-Si界面处产生较大的能带弯曲,促进界面电荷分离。此外,Co的加入会产生丰富的Ni^(3+)和氧空位(Ov),作为活性位点可以加速OER动力学过程,协同促进PEC过程中的水氧化的活性。令人鼓舞的是,通过将Ni_(0.9)Fe_(0.05)Co_(0.05)/p^(+)n-Si光阳极连接到廉价的硅太阳能电池上,所制备的集成光伏/PEC(PV/PEC)器件实现了无偏压下高达12.0%的太阳制氢能量转换效率。这项工作提供了一种简单的方法来设计高效、稳定的n-Si基光阳极,并对其构效关系有了深刻的理解;这种方法制备的材料在集成低成本PV/PEC器件用于无辅助太阳能驱动水分解方面具有巨大的潜力。n-Type silicon(n-Si),with surface easily oxidized and passivated in an aqueous electrolyte,has suffered from sluggish oxygen evolution reaction(OER)kinetics for photoelectrochemical(PEC)water splitting.Herein,a trimetallic Ni_(0.9)Fe_(0.05)Co_(0.05)protective layer is successfully electrodeposited on a p^(+)n-Si substrate by underpotential deposition.The prepared Ni_(0.9)Fe_(0.05)Co_(0.05)/p^(+)n-Si photoanode exhibits excellent stability and activity for PEC water oxidation,with a low onset potential of 0.938 V versus a reversible hydrogen electrode(RHE)and a remarkable photocurrent density of about 33.1 mA∙cm^(-2)at 1.23 V versus RHE,which significantly outperforms the Ni/p^(+)n-Si photoanode as a reference.It is revealed that the incorporation of Fe into the Ni layer creates a large band bending at the Ni_(0.9)Fe_(0.05)Co_(0.05)/p^(+)n-Si interface,promoting interfacial charge separation.Moreover,the incorporation of Co produces abundant Ni^(3+)and oxygen vacancies(Ov)that act as active sites to accelerate the OER kinetics,synergistically contributing to a major enhancement of PEC water oxidation activity.Encouragingly,by connecting the Ni_(0.9)Fe_(0.05)Co_(0.05)/p^(+)n-Si photoanode to an inexpensive Si solar cell,an integrated photovoltaic/PEC(PV/PEC)device achieved a solar-to-hydrogen conversion efficiency of as high as 12.0%without bias.This work provides a facile approach to design efficient and stable n-Si-based photoanodes with a deep understanding of the structure–activity relationship,which exhibits great potential for the integration of low-cost PV/PEC devices for unassisted solar-driven water splitting.

关 键 词：欠电位沉积 电极电势 阳极连接 硅太阳能电池 能量转换效率 太阳能制氢 能带弯曲 光阳极 

分 类 号：TQ116.2[化学工程—无机化工] TM914.4[电气工程—电力电子与电力传动]