用于能量转换和存储应用的多孔镍和稀土金属（Ce、Ho 和 Eu）共掺杂 TiO2 纳米结构的设计,New Journal of Chemistry

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用于能量转换和存储应用的多孔镍和稀土金属（Ce、Ho 和 Eu）共掺杂 TiO2 纳米结构的设计
New Journal of Chemistry ( IF 2.7 ) Pub Date : 2023-01-09 , DOI: 10.1039/d2nj05999a
Amna Bashir ₁ , Abid Inayat ₂ , Rabia Bashir ₃ , Sadaf Jamil ₂ , Syed Mustansar Abbas ₄ , Muhammad Sultan ₅ , Azhar Iqbal ₂ , Zareen Akhter ₂

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在目前的工作中，通过简单的水热法合成了具有高表面积和电荷密度的TiO ₂纳米结构，并通过与过渡金属（镍）和稀土金属（铕、铈和钬）共掺杂进一步改性。 . 不同的表征工具（即XRD、BET 表面积、FTIR、拉曼、PL、SEM、TEM、XAS、XPS 和 DRS）已用于检查共掺杂对电学、形态和结构特性的影响TiO ₂纳米结构。_{FTIR、Raman 和 XRD 结果证实了 TiO 2}纳米结构的成功共掺杂。与未掺杂和单掺杂 TiO2 相比，共掺杂纳米结构的高表面积₂从 BET 测量得到证实。通过XPS 和 XAS 研究进一步阐明了各种氧化态掺杂剂的存在FE-SEM 和 TEM 揭示了相互连接的介孔型纳米结构的形成，粒径小于 100 nm。通过执行循环伏安法、线性扫描伏安法、恒电流充放电和电化学阻抗测量来评估合成纳米结构的超级电容行为。比电容值 ( C _sp ) 表明稀土金属共掺杂到 TiO₂结构中导致靶材的电容增强。在 Ni-Ho-3 样品（740 F g^-1)，其次是 Ni-Eu-3 (630 F g ^-1 )、Ni-Ce-3 (552 F g ^-1 ) 和 Ni-5 (545 F g ^-1 )，与纯 TiO ₂相比(240 F g ^-1 )。^{此外，Ni-Ho-3 电极还表现出更好的循环稳定性，在 5 A g -1}的高电流密度下循环 1000 次后容量保持率为 97% 。水氧化研究还表明，所有掺杂的 TiO ₂纳米催化剂均显示出增强的析氧反应 (OER) 和析氢反应 (HER) 活性。Ni-Eu-3、Ni-5、Ni-Ce-3 和 Ni-Ho-3在 10 mA cm ^-2时的 OER 过电位值分别为 520、550、600 和 620 mV。_{未掺杂 TiO 2}的塔菲尔斜率、Ni-5、Ni-Eu-3、Ni-Ce-3 和 Ni-Ho-3 的测量值分别为 151、143、134、141 和 137 mV dec ^-1。Ni-Eu-3 的最小 Tafel 斜率表明其在所有选定样品中的最高 OER 效率。与其他样品相比，Ni-Ho-3 样品的塔菲尔斜率也较低。共掺杂纳米结构的卓越性能归功于具有更多电活性位点、高电荷密度和更好的电荷转移（EIS 结果）的介孔结构的发展。

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Design of porous Ni and rare earth metal (Ce, Ho, and Eu) Co-doped TiO2 nanoarchitectures for energy conversion and storage applications

In the current work, TiO₂ nanoarchitectures with high surface area and charge density have been synthesized by a facile hydrothermal method and further modified via co-doping with a transition metal (nickel) and rare-earth metals (europium, cerium, and holmium). Different characterization tools (i.e., XRD, BET surface area, FTIR, Raman, PL, SEM, TEM, XAS, XPS, and DRS) have been used to check the effect of co-doping on the electrical, morphological, and structural properties of the TiO₂ nanoarchitectures. The FTIR, Raman, and XRD results confirmed the successful co-doping of the TiO₂ nanoarchitectures. The high surface area of the co-doped nanoarchitectures as compared to undoped and singly doped TiO₂ was confirmed from BET measurements. The presence of dopants in various oxidation states was further elucidated via XPS and XAS studies. FE-SEM and TEM revealed the formation of interconnected, mesoporous-type nanoarchitectures, with particle sizes less than 100 nm. The supercapacitive behavior of synthesized nanoarchitectures was evaluated by performing cyclic voltammetry, linear scan voltammetry, galvanostatic charge–discharge, and electrochemical impedance measurements. The specific capacitance values (C_sp) indicate that the co-doping of rare-earth metals into the TiO₂ structure results in enhanced capacitance of the target materials. The highest capacitive behavior was observed in the Ni-Ho-3 sample (740 F g⁻¹), followed by Ni-Eu-3 (630 F g⁻¹), Ni-Ce-3 (552 F g⁻¹), and Ni-5 (545 F g⁻¹), as compared to that of pure TiO₂ (240 F g⁻¹). Furthermore, the Ni-Ho-3 electrode also showed better cyclic stability with 97% capacity retention after 1000 cycles at a high current density of 5 A g⁻¹. The water oxidation studies also showed that all the doped TiO₂ nano-catalysts show enhanced oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activity. The OER overpotential values at 10 mA cm⁻² for Ni-Eu-3, Ni-5, Ni-Ce-3, and Ni-Ho-3 are 520, 550, 600, and 620 mV, respectively. The Tafel slopes of undoped TiO₂, Ni-5, Ni-Eu-3, Ni-Ce-3, and Ni-Ho-3 are measured to be 151, 143, 134, 141, and 137 mV dec⁻¹, respectively. The smallest Tafel slope of Ni-Eu-3 indicated its highest OER efficiency among all the selected samples. As compared with the other samples, Ni-Ho-3 sample also showed a lower value for the Tafel slope. The superior performance of co-doped nanoarchitectures was credited to the development of mesoporous structures with more electroactive sites, high charge density, and better charge transfer (EIS results).

更新日期：2023-01-09

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